Comparison of the effects of melatonin and pentoxifylline on carbon tetrachloride-induced liver toxicity in mice

The purpose of the study was to determine whether along and in combination melatonin (MLT) and pentoxlfylline (PTX) exerted beneficial effects on histopathological changes and changes in oxidant and antioxidant systems in liver caused by CCl₄-induced liver toxicity in mice. Mice were randomly divided into six groups: control, olive oil, toxicity, MLT, PTX, PTX+MLT. MLT 10 mg/kg/day, PTX 50 mg/kg/day, and the same individual doses in MLT+PTX combination were given intraperitoneally to mice for 7 day. CCl₄ 0.8 mg/kg/day was administered on the 4th, 5th, and 6th days of therapy in all groups except the control and olive oil groups. In the toxicity group, increased concentrations of malondialdehyde (MDA) and lipid hydroperoxides (LOOH) and decreased glutathione peroxidase (GSH-Px) and catalase (CAT) activities were found compared to the control and olive oil groups (p < 0.05). Compared to the toxicity group, both the PTX group and the PTX+MLT group had decreased MDA and LOOH levels, whereas MLT reduced only LOOH levels (p < 0.01). MLT, PTX and MLT+PTX increased the GSH-Px and CAT activities compared to the toxicity group (p < 0.05). MLT increased CAT activity compared to PTX and MLT+PTX (p < 0.05). Superoxide dismutase enzyme activity did not change in any group (p < 0.05). Histopatholically, ballooning, degeneration, apoptosis, and bridging necrosis were seen in the toxicity group. MLT, PTX and MLT+PTX decreased the apoptosis and bridging necrosis (p < 0.01), and PTX and MLT+PTX decreased balloon degeneration compared to the toxicity group (p < 0.01). These results indicate that administration of PTX and MLT alone and in combination before onset of liver toxicity might prevent the oxidative damage by reducing oxidative stress and increasing antioxidant enzyme levels.     

Antioxidative effect of melatonin on cryopreserved ovarian tissue in mice

Cryopreservation of ovarian tissues (OTs) has become the most effective way to preserve the fertility of female cancer patients. However, cryopreservation of OTs is still relatively at an experimental stage. The aim of study is to examine the effect of melatonin (MTL) on cryopreserved-thawed OTs. Fragments of OTs were cryopreserved in medium containing different concentrations (0 mM, 0.001 mM, 0.01 mM, 0.1 mM and 1 mM) of MLT. The endogenous enzymes (GSH-PX, GSH, SOD, CAT and T-AOC), MDA and ROS levels were all evaluated after cryopreservation. Our results showed that the 0.1 mM of MLT significantly improved the survival and diameter of follicles (P < 0.001). Meanwhile, the antioxidant enzymes activities (including GSH-PX, GSH, SOD, CAT and T-AOC) were enhanced and MDA content were significantly decreased in 0.1 mM of MLT group compared to other groups (P < 0.001). Additionally, compared to the control group, MTL of 0.1 mM resulted in a significantly lower ROS level. In conclusion, MLT protects the quality of cryopreserved OTs by decreasing oxidative stress level and the optimal concentration is 0.1 mM.     

Ellagic acid improved diabetes mellitus-induced testicular damage and sperm abnormalities by activation of Nrf2

Diabetes mellitus induces testicular damage, increases sperm abnormalities, and impairs reproductive dysfunction due to induction of endocrine disturbance and testicular oxidative stress. This study evaluated the reproductive protective effect of ellagic acid (EA) against testicular damage and abnormalities in sperm parameters in Streptozotocin (STZ)-induced diabetic rats (T1DM) and examined some possible mechanisms of protection. Adult male rats were segregated into 5 groups (n = 12 rat/each) as control, control + EA (50 mg/kg/day), T1DM, T1DM + EA, and T1DM + EA + brusatol (an Nrf-2 inhibitor) (2 mg/twice/week). All treatments were conducted for 12 weeks, daily. EA preserved the structure of the seminiferous tubules, prevented the reduction in sperm count, motility, and viability, reduced sperm abnormalities, and downregulated testicular levels of cleaved caspase-3 and Bax in diabetic rats. In the control and diabetic rats, EA significantly increased the circulatory levels of testosterone, reduced serum levels of FSH and LH, and upregulated Bcl-2 and all steroidogenic genes (StAr, 3β-HSD1, and 11β-HSD1). Besides, it reduced levels of ROS and MDA but increased levels of GSH and MnSOD and the transactivation of Nrf2. All these biochemical alterations induced by EA were associated with increased activity and nuclear accumulation of Nrf2. However, all these effects afforded by EA were weakened in the presence of brusatol. In conclusion, EA could be an effective therapy to alleviated DM-induced reproductive toxicity and dysfunction in rats by a potent antioxidant potential mediated by the upregulation of Nrf2.     

Neuroprotective effect of melatonin on radiation-induced oxidative stress and apoptosis in the brainstem of rats

This study aimed to determine the effects of melatonin on irradiation-induced apoptosis and oxidative stress in the brainstem region of Wistar rats. Therefore, the animals underwent whole-brain X-radiation with a single dose of 25 Gy in the presence or absence of melatonin pretreatment at a concentration of 100 mg/kg BW. The rats were allocated into four groups (10 rats in each group): namely, vehicle control (VC), 100 mg/kg of melatonin alone (MLT), irradiation-only (RAD), and irradiation plus 100 mg/kg of melatonin (RAM). An hour before irradiation, the animals received intraperitoneal (IP) melatonin and then were killed after 6 hr, followed by measurement of nitric oxide (NO), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), and total antioxidant capacity (TAC) in the brainstem region. Furthermore, the western blot analysis technique was performed to assess the caspase-3 expression level. Results showed significantly higher MDA and NO levels in the brainstem tissues for the RAD group when compared with the VC group (p < .001). Moreover, the irradiated rats exhibited a significant decrease in the levels of CAT, SOD, GPx, and TAC (p < .01, p < .001, p < .001, and p < .001, respectively) in comparison to the VC group. The results of apoptosis assessment revealed that the expression level of caspase-3 significantly rose in the RAD group in comparison with the VC group (p < .001). Pretreatment with melatonin ameliorated the radiation-induced adverse effects by decreasing the MDA and NO levels (p < .001) and increasing the antioxidant enzyme activities (p < .001). Consequently, the caspase-3 protein expression level in the RAM group showed a significant reduction in comparison with the RAD group (p < .001). In conclusion, melatonin approximately showed a capacity for neuroprotective activity in managing irradiation-induced oxidative stress and apoptosis in the brainstem of rats; however, the use of melatonin as a neuroprotective agent in humans requires further study, particularly clinical trials.     

The relative efficacy of aminoguanidine and pentoxifylline in modulating endotoxin-induced cardiac stress

This study investigates the effect of aminoguanidine (AG), a selective inducible nitric oxide synthase (iNOS) inhibitor, and pentoxifylline (PTX), a tumour necrosis factor–alpha (TNF‐α) inhibitor, on lipopolysaccharide (LPS)‐induced cardiac stress. Rats were divided into four groups: group I served as a control, group II (LPS) received a single intraperitoneal injection of LPS (10 mg·kg^–1), group III (LPS+AG) and group IV (LPS+PTX) were injected with either AG (100 mg·kg^–1) or PTX (150 mg·kg^–1) intraperitoneally 10 days prior to LPS administration. Normalization of cardiac levels of nitrite/nitrate (NO_X), malondialdehyde (MDA), glutathione (GSH), heme oxygenase‐1 (HO‐1), glutathione peroxidase (GPx) and Na⁺, K⁺‐ATPase activities was evident in the AG group. Both AG and PTX decreased the elevated serum TNF‐α levels, the activities of lactate dehydrogenase (LDH), creatine kinase (CK) and cardiac myeloperoxidase (MPO). The levels of adenosine triphosphate (ATP), adenosine diphosphate (ADP) and phosphocreatine (PCr) were enhanced following AG and PTX pretreatments. Calcium (Ca²⁺) levels were altered, and the histopathological observations supported the described results. Conclusively, the study highlights the cardioprotective potential of AG and PTX with superior results from AG. These findings reveal the relative contribution of nitric oxide and TNF‐α to oxidative stress and energy failure during endotoxemia. Copyright © 2011 John Wiley & Sons, Ltd.     

Antioxidant enzymes and melatonin levels in patients with bronchial asthma and chronic obstructive pulmonary disease during stable and exacerbation periods

An imbalance between oxidative stress and antioxidative capacity may play an important role in the development and progression of bronchial asthma (BA) and chronic obstructive pulmonary disease (COPD). We carried out a study to assess the systemic oxidant–antioxidant status during the exacerbation and the stable period in patients with BA and COPD. A total of 33 patients, 16 with BA and 17 with COPD were included in the study. During the exacerbation and the stable periods, levels of malondialdehyde (MDA), activities of superoxide dismutase (SOD), glutathione peroxidase (GSH‐Px), glutathione reductase (GRd), and catalase (CAT) in erythrocytes and serum melatonin concentrations were investigated. Blood counts, respiratory functions, and blood gases of the patients were also performed. During an exacerbation period of BA, despite the decreases in GSH‐Px, GRd and melatonin levels, MDA and CAT levels, and the white blood cell count, the percentage of eosinophils were significantly higher than in the stable period. Also, it was found that FEV₁/L (where FEV₁ is the forced expiratory volume in 1 s), FVC/L (where FVC is forced vital capacity), PEF/L/s (where PEF is peak expiratory flow), pO₂ (where pO₂ is oxygen pressure) levels increased during the stable period in patients with BA. MDA and SOD values were higher in the exacerbation period than in the stable period although GSH‐Px, GRd, melatonin, pH, and pO₂ values were lower in the exacerbation period than in the stable period. The blood counts and the respiratory function tests did not change between the exacerbation and the stable period of patients with COPD significantly. In conclusion, we observed that oxidative stress in the exacerbation period of patients with BA and COPD increased whereas the antioxidant enzymes and melatonin values reduced. The episodes of BA or COPD might be associated with elevated levels of oxidative stress. Copyright © 2009 John Wiley & Sons, Ltd.     

Evaluation of the Anti‐Diabetic Activity of Polysaccharide from Cordyceps cicadae in Experimental Diabetic Rats

Cordyceps cicadae is a medicinal fungus used in treating night sweat, childhood convulsions, vision improvement and pain. This study was designed to evaluate the anti‐diabetic activity of the crude polysaccharide (SHF) from the mycelium and body portion of C. cicadae. Diabetes mellitus was induced in the rat with a single intravenous injection of alloxan monohydrate (150 mg/kg). In other to evaluate the anti‐diabetic effects of C. cicadae polysaccharide in alloxan‐induced diabetic rats, the crude polysaccharide (SHF at 100, 200 and 400 mg/kg body weight) and glibenclamide were administered orally to diabetic rats for 30 days. Blood glucose level, total cholesterol (TC), triglyceride (TG), low density lipoprotein (LDL), high density lipoprotein (HDL), alanine transaminase (ALT), aspartate aminotransferase (AST), alkaline phosphate (ALP), creatinine (CREA), urea, malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH) were determined. SHF showed significant reduction in blood glucose in diabetic rats. Treatment of diabetic rats also resulted an improvement in body weights, increased HDL, SOD and GSH, as well as decreased TC, TG, LDL, MDA, urea, CREA, ALT, AST and ALP. These results suggested that C. cicadae polysaccharide displayed anti‐hyperglycemic, anti‐hyperlipidemic and antioxidant activities and could be a promising therapeutic source in managing diabetes mellitus and its associated complications.     

Effects of Selenium and Vitamin E,in Addıtıon to Melatonin,Against Oxidative Stress Caused by Cadmium in Rats

The present study was carried to evaluate the protective effects of melatonin alone and vitamin E with selenium combination against high dose cadmium-induced oxidative stress in rats. The control group received subcutanous physiological saline. The first study group administered cadmium chloride (CdCl₂) by subcutaneous injection of dose of 1 mg/kg. The second study group administered cadmium plus vitamin E with selenium (1 mg/kg sodium selenite with 60 mg/kg vitamin E); the third study group administered cadmium plus 10 mg/kg melatonin (MLT); the fourth study group administered CdCl₂ plus a combination of melatonin in addition to vitamin E and selenium for a month. Determination levels of plasma malondialdehyde (MDA), glutathione peroxidase (GSH-Px), blood superoxide dismutase (SOD), creatinine alanine transaminase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), blood urea nitrogen (BUN), and urea were measured in serum. In only CdCl₂ administered group, the MDA, creatinine, ALT, AST, ALP, and urea levels in the serum were significantly higher than the control group (p < 0.05). Whereas in all other groups, this values were significantly lower than the only CdCl₂ administered group (p < 0.05). Erythrocytes GSH-Px, serum SOD activities of only CdCl₂ received group were significantly lower than the control group (p < 0.05). In conclusion, vitamin E + Se, melatonin and vitamin E, and Se, in addition to MLT combinations, had protective effects against high dose cadmium-induced oxidative damage.     

Effects of X-ray radiation on lipid peroxidation and antioxidant systems in rabbits treated with antioxidant compounds

The aim of this study was to investigate the effects of supplemental antioxidant vitamins and minerals on lipid peroxidation and on the antioxidant systems in rabbits exposed to X-rays. The rabbits were divided into two experimental groups and one control group, each group containing seven rabbits. The first group (VG) received daily oral doses of vitamin E (460 mg/kg live weight) and vitamin C (100 mg/kg live weight). The second group (MG) was fed a mineral-enriched diet that contained 60 mg manganese chloride, 40 mg zinc sulfate, and 5 mg copper sulfate per kilogram of feed. The third group served as controls and received only a standard diet. Blood samples were obtained before and after the supplementation with vitamins or minerals, as well as before and after irradiation with a total dose of 550-rad X-rays. The blood samples were analyzed for their content of malondialdehyde (MDA), plasma vitamins C and E, retinol, reduced glutathione (GSH), and glutathione peroxidase activity (GPx). After irradiation, the control group showed increased levels of MDA and activity of GPx (p<0.05), whereas the levels of GSH, vitamin C, and vitamin E were decreased. In the VG, the concentration of MDA was lower (p<0.05), and the concentration of GSH and vitamins C and E were higher (p<0.05) when compared to controls. In the MG, the concentrations of MDA, GSH, vitamin C, and retinol were not affected by the mineral administration and radiation. The level of vitamin E in the MG increased with mineral administration (p<0.05), but decreased after irradiation (p<0.05). For the control group, the level of GSH was higher than in the two experimental groups. After irradiation, the VG animals had vitamin E and C levels that were higher than in MG and control groups (p<0.05). The activity of GPx was not affected by vitamin or mineral supplementation or by irradiation. We conclude that the supplementation with antioxidant vitamins and minerals may serve to reinforce the antioxidant systems, thus having a protective effect against cell damage by X-rays.     

Erdosteine modulates radiocontrast‐induced hepatotoxicity in rat

It has been suggested that reactive oxygen species (ROS) plays an important role in radio contrast media (RCM)‐induced ischemia reperfusion tissue injury although antioxidants may have protective effects on the injury. We investigated the effects of erdosteine as an antioxidant agent on RCM‐induced liver toxicity in rats by evaluation of lipid peroxidation (as TBARS), catalase (CAT), superoxide dismutase (SOD), reduced glutathione (GSH) and glutathione peroxidase (GSH‐Px) values and histological evaluation. Twenty‐one rats were equally divided into three groups as follows: control, RCM, and RCM plus erdosteine. RCM was intraperitoneally administered for 1 day. Erdosteine was administered orally for 2 days after RCM administration. Liver samples were taken from the rats and they homogenized in a motor‐driven tissue homogenizer. TBARS levels were significantly (p < 0.005) higher in RCM group than in control although SOD activities significantly (p < 0.05) decreased in RCM group. TBARS levels were lower in RCM plus erdosteine group than in control although SOD activity and GSH level increased (p < 0.05) in liver as compared to RCM alone. Erdosteine showed also histopathological protection (p < 0.0001) against RCM induced hepatotoxicity. GSH‐Px and CAT activities were not statistically changed by the erdosteine. According to our results, it can be concluded that radiocontrast media can induce oxidative stress in liver as suggested by previous studies. Erdosteine seems to be protective agent on the radiocontrast media‐induced liver toxicity by inhibiting the production of ROS via the enzymatic antioxidant system. Copyright © 2009 John Wiley & Sons, Ltd.     

Effect of Selenium Supplementation on Lipid Peroxidation,Antioxidant Enzymes,and Lactate Levels in Rats Immediately After Acute Swimming Exercise

The present study aims to evaluate the effect of selenium supplementation on lipid peroxidation and lactate levels in rats subjected to acute swimming exercise. Thirty-two adult male rats of Sprague–Dawley type were divided into four groups. Group 1, control; group 2, selenium-supplemented; group 3, swimming control; group 4, selenium-supplemented swimming group. The animals in groups 2 and 4 were supplemented with (i.p.) 6 mg/kg/day sodium selenite for 4 weeks. The blood samples taken from the animals by decapitation method were analyzed in terms of erythrocyte-reduced glutathione (GSH), serum glutathione peroxidase (GPx) and superoxide dismutase (SOD), and plasma malondialdehyde (MDA) and lactate using the colorimetric method, and serum selenium values using an atomic emission device. In the study, the highest MDA and lactate values were found in group 3, while the highest GSH, GPx and SOD values were obtained in group 4 (p < 0,001). Group 2 had the highest and group 3 had the lowest selenium levels (p < 0,001). Results of the study indicate that the increase in free radical production and lactate levels due to acute swimming exercise in rats might be offset by selenium supplementation. Selenium supplementation may be important in that it supports the antioxidant system in physical activity.     

Changes in serum inflammatory factor interleukin-6 levels and pathology of carotid vessel walls of rats with chronic periodontitis and diabetes mellitus after the periodontal intervention

ObjectiveThe effects of the periodontal intervention on rats with type-II diabetes mellitus (T2DM) and chronic periodontitis (CP) were explored through observing the changes in carotid artery pathology and interleukin-6 (IL-6) levels.MethodsThe rats were randomly divided into 5 groups, i.e. group A (the normal control group), group B (the T2DM control group), group C (the CP control group), group D (the T2DM + CP group), and group E (the periodontal intervention T2DM + CP group). Blood samples of rats were collected from angular veins respectively at the following 5 time nodes: 1 week before the intervention (T1), 1 week after the intervention (T2), 3 weeks after the intervention (T3), 5 weeks after the intervention (T4), and 7 weeks after the intervention (T5); IL-6 concentrations before and after the intervention were determined by the enzyme-linked immunosorbent assay (ELISA), and the pathology of carotid arteries were observed by the Hematoxylin-Eosin (HE) stain.ResultsThe pathological results of carotid arteries showed that the blood vessels of rats in group A were normal in morphology; most of the carotid artery vessel walls of rats in groups B, C, and D were significantly thickened and the fibers were disorderly arranged; the increased thickness of vessel walls of rats in group E was reduced, a small number of foam cells and inflammatory cells were observed, and the irregular arrangement of fibers was improved. In terms of the IL-6 concentrations, during the period of T1-T5, in groups B, C, and D, the IL-6 concentrations in rats were increased (P < 0.05); after the periodontal intervention, in group E, the IL-6 concentrations in rats were first increased then decreased (P < 0.05).ConclusionIn terms of the long-term effects, periodontal intervention may reduce the inflammations of patients with diabetes mellitus and periodontitis and improve the lesions of carotid arteries.     

Involvement of glutathione metabolism in Eichhornia crassipes tolerance to arsenic

• Aquatic macrophytes are potentially useful for phytoremediation programmes in environments contaminated by arsenic (As). Biochemical and physiological modification analyses in different plant parts are important to understand As tolerance mechanisms.
• The objective was to evaluate glutathione metabolism in leaves and roots of Eichhornia crassipes (Mart.) Solms treated to As. Specimens of E. crassipes were cultured for 3 days in Clark's nutrient solution containing 7 μm As. The enzymes ATP sulphurylase (ATPS), glutathione reductase (GR), glutathione peroxidase (GSH‐Px), glutathione sulphotransferase (GST) and γ‐glutamylcysteine synthetase (γ‐ECS) activity, glutathione content, total protein and non‐protein thiols were evaluated.
• The ATPS activity increased in roots. GR activity in leaves and GSH‐Px in roots were lower. GST activity was higher in roots and lower in leaves, and γ‐ECS activity was higher in leaves. Glutathione levels were lower, total thiol levels were higher and non‐protein levels did not change in E. crassipes leaves and roots. Exposure to As increased enzyme activity involved with sulphur metabolism, such as ATPS. Higher GR activity and lower GSH‐Px indicate increased glutathione conjugation to As due to increased GSH availability. The higher GST activity indicates its participation in As detoxification and accumulation through As GSH conjugation. Changes in glutathione and thiol levels suggest high phytochelatin synthesis.
• In conclusion, the increments in ATPS, GR, GST and γ‐ECS activity indicate that these enzymes are involved in GSH metabolism and are part of the E. crassipes As detoxification mechanism.

     

The effects of resveratrol on cyclooxygenase-1 and cyclooxygenase-2 mRNA and protein levels in diabetic rat kidneys

Cyclooxygenase (COX), which have the isoforms of COX-1 and COX-2, is the key enzyme of prostaglandins biosynthesis. Especially, COX-2 is induced in inflammatory disease such as Diabetes Mellitus (DM). Resveratrol (RSV), a natural antioxidant, has a beneficial role in prevention of inflammatory disease. We investigated the changes of COX-1 and COX-2 mRNA expression and protein level in diabetic rat kidney after RSV treatment. Three months-old, 44 Wistar albino male rats, which were divided into six groups such as control group, sodium citrate buffer (sham control) group, diabetic group (DM), Dimethyl Sulfoxide induced control group, RSV treated sham control group (RSV) and RSV treated diabetic group (DM + RSV) were used for the study. Experimental diabetes was induced by intraperitoneal injection of 55 mg/kg Streptozotocin. After the induction of chronic diabetes 10 mg/kg per day RSV was administered intraperitoneally for 4 weeks. In this study. RSV has no significant effect on COX-1 mRNA expression in diabetic rat kidney (P > 0.05). Immunohistochemical study showed that COX-1 expression was slightly inhibited in RSV group and was not significantly supressed in DM + RSV group. When comparing control and treated groups, there were no significant differences in COX-2 mRNA or protein levels (P > 0.05). In conclusion, our results indicate that resveratrol do not significantly affect COX gene and protein expression. Therefore, different therapy strategies such as combination with other antidiabetic drugs may tried in STZ induced animal model for reducing diabetic symptoms and altering COX-1 and COX-2 mRNA or protein levels.     

Imbalanced oxidant and antioxidant ratio in myotonic dystrophy type 1

Abstract

Myotonic dystrophy type 1 (DM1) is the most common form of muscular dystrophy affecting adults and is due to trinucleotide sequence (CTG) in the 3′ UTR region of DMPK gene located at 19q13.3 chromosome. The pathogenic mechanisms of multisystemic involvement of DM1 are still unclear. The increased levels of reactive oxygen species/free radicals and lipid peroxides and decreased antioxidant levels play an important role in the pathogenesis of DM1. Present study includes 20 DM1 patients and 40 age- and sex-matched controls. Malonilaldehyde (MDA), superoxide dismutase (SOD), glutathione peroxidise (GPX), glutathione-S-transferase (GST), reduced glutathione (GSH), and TAS levels were measured and its association with clinical phenotype were evaluated. Results revealed significantly higher levels of MDA (p = 0.002), SOD (p = 0.006), and TAS p = 0.004) and lower level of GPX (p = 0.003), GST (P < 0.001) and GSH (P = 0.016) in DM1 patients. A significant negative correlation of MDA level with dyspepsia and CK-MB and GST level with serum SCK, CK-MB, and diabetes were observed. However, a significant positive correlation of SOD level with serum CK-MB, CK-MM, and diabetes and negative correlation with facial weakness were noted. Though, GSH level had significant positive correlation with learning and writing disability, speech, and languages disability yet found negative correlation with duration of disease. The GPX and TAS showed no correlation with any clinical findings. Our data further support the pathogenic role of oxidative stress in DM1 of Indian origin and support the opportunity to undertake clinical trials with antioxidants in this disorder.     

Effect of Zinc and Melatonin on Oxidative Stress and Serum Inhibin-B Levels in a Rat Testicular Torsion–Detorsion Model

The present study was aimed to examine the effects of 3-week zinc and melatonin administration on testicular tissue injury and serum Inhibin-B levels caused by unilateral testicular torsion–detorsion in rats. The study was performed on 60 Wistar Albino-type adult male rats. The animals were allocated to 6 groups in equal numbers. 1. Control; 2. Sham; 3. Ischemia–reperfusion; 4. Zinc + ischemia–reperfusion; 5. Melatonin + ischemia–reperfusion; 6. Zinc + melatonin + ischemia–reperfusion. Zinc and melatonin were administered before ischemia–reperfusion at doses of 5 and 3 mg/kg respectively, by intraperitoneal route for a period of 3 weeks. Testicular torsion–detorsion procedures consisted of ischemia for 1 h and then reperfusion for another hour of the left testis. Blood and testicular tissue samples were collected to analyze erythrocyte and tissue GSH and plasma and tissue MDA, Inhibin-B levels. The highest erythrocyte and testis GSH values were found in zinc, melatonin, and zinc + melatonin groups (p < 0.001). Torsion–detorsion group has significantly lower erythrocyte GSH levels and higher plasma MDA values (p < 0.001). Serum inhibin-B and spermatogenic activity levels in the torsion–detorsion group were also significantly lower than those in the other groups (p < 0.001). However, zinc-, melatonin-, and melatonin + zinc-supplemented groups have higher inhibin-B and spermatogenetic activity (p < 0.001). The results of the study show that zinc, melatonin, and melatonin + zinc administration partially restores the increased oxidative stress, as well as the reduced inhibin-B and spermatogenic activity levels in testes ischemia–reperfusion in rats. Suppressed inhibin-B levels in the testicular tissue may be a marker of oxidative stress.     

Entrainment of Circadian Programs

Circadian rhythms were recently proposed as a measure of physiological state and prognosis in disorders of consciousness (DOC). So far, melatonin regulation was never assessed in vegetative state (VS). Aim of our research was to investigate the nocturnal melatonin levels and light-induced melatonin suppression in a cohort of VS patients. We assessed six consecutive patients (four men, age 33.3?±?9.3 years) with post-traumatic VS and nine age-matched healthy volunteers (five men, age 34.3?±?8.9 years) on two consecutive nights: one baseline and one light exposure night. During baseline, night subjects were in bed in a dim (<5?lux) room from 10?pm to 8?am. Blood samples were collected hourly 00:30–3:30?am (00:30?=?MLT1; 1:30?=?MLT2; 2:30?=?MLT3; and 3:30?=?MLT4). Identical setting was used for melatonin suppression test night, except for the exposure to monochromatic (470?nm) light from 1:30 to 3:30?am. Plasma melatonin levels were evaluated by radioimmunoassay. Magnitude of melatonin suppression was assessed by melatonin suppression score (caMSS) and suppression rate. We searched for group differences in melatonin levels, differences between repeated samples melatonin concentrations during baseline night and light exposure night, and light-induced suppression of melatonin secretion. During baseline night, controls showed an increase of melatonin (MLT4 vs MLT1, p?=?0.037), while no significant changes were observed in VS melatonin levels (p?=?0.172). Baseline night MLT4 was significantly lower in VS vs controls (p?=?0.036). During light-exposure night, controls displayed a significant suppression of melatonin (MLT3 and MLT4 vs MLT2, p?=?0.016 and 0.002, respectively), while VS patients displayed no significant changes. The magnitude of light-induced suppression of melatonin levels was statistically different between groups considering control adjusted caMSS (p?=?0.000), suppression rate (p?=?0.002) and absolute percentage difference (p?=?0.012). These results demonstrate for the first time that VS patients present an alteration in night melatonin secretion and reduced light-induced melatonin suppression. These findings confirm previous studies demonstrating a disruption of the circadian system in DOC and suggest a possible benefit from melatonin supplementation in VS.     

Cross‐effects of dietary probiotic supplementation and rearing temperature on antioxidant responses in European seabass [Dicentrarchus labrax (Linnaeus, 1758)] juveniles

Temperature modulates the metabolism in both fish and bacteria and therefore the effect of probiotic bacteria on its host may vary accordingly. The current study aim was to evaluate the effect of probiotic supplementation (Bacillus sp., Lactobacillus sp., Enterococcus sp., Pediococcus sp.) in juvenile seabass, Dicentrarchus labrax, when reared under different temperatures (17, 20 and 23°C). A control diet was tested against a probiotic‐supplemented diet, with a concentration of 3 × 10⁹ CFU probiotic/kg diet. Antioxidant responses (TG, GSH, GSSG, GR, CAT and GSTs) and lipid peroxidation (LPO) were evaluated after 70 days of dietary probiotic supplementation. An effect of temperature was observed on LPO, which increased significantly in fish reared at 17°C (p < .05) compared to the 20 and 23°C groups. Total glutathione (TG) was significantly higher in the probiotic treatments in fish reared at 17 and 20°C (p < .05). In addition, a probiotic temperature interaction was observed for TG, reduced glutathione (GSH) levels, and for reduction of the oxidized glutathione ratio (GSH/GSSG; p < .05). In conclusion, the current study showed a strong temperature effect on oxidative stress responses, with an anti‐oxidant role of dietary probiotic supplementation at different rearing temperatures.     

Contralateral Retinal Dopamine Decrease and Melatonin Increase in Progression of Hemiparkinsonium Rat

Both dopamine (DA) and melatonin (MLT) are abundant neuromodulators located in vertebrate retina. The retinal DA deficiency and variations in MLT levels have been linked to Parkinson’s disease (PD). No studies have investigated the ipsilateral and contralateral DA and MLT in retina and their relationships in 6-hydroxydopamine (6-OHDA) induced hemiparkinsonian rats. We established PD rat model by unilateral injection of 6-OHDA into the right substantia nigra and the right medial forebrain bundle. Eye tissue was collected and the levels of MLT and DA were measured twice daily at 10:00 and 22:00. The concentrations of DA and its metabolites, 3,4-dihydroxyphenylacetic (DOPAC) and homovanillic acid (HVA), as well as MLT were determined by HPLC. The results show that DA levels in the eye contralateral to the side of a unilateral intracerebral 6-OHDA lesion significantly decreased (P < 0.001). Both the ratios of DOPAC/DA and HVA/DA were increased in comparison with the vehicle groups after 3 weeks post-lesion. The concentrations of MLT at 10:00 and 22:00 in both eyes were distinctly increased compared with the vehicle groups (P < 0.05). The change of DA and its metabolites, as well as MLT appeared to correlate well with the rotation behavior of rats. These findings suggest that rats receive a unilateral intracerebral injection of 6-OHDA that mainly causes the contralateral eye destruction of DA-containing neurons. Increased retinal MLT level probably is associated with the progression of PD.     

Effect of Zinc Supplementation on Antioxidant Activity in Young Wrestlers

This study aims to examine the effect of zinc supplementation on free-radical formation and antioxidant system in individuals who are actively engaged in wrestling as a sport. The study registered a total of 40 male subjects, of whom 20 were wrestlers and 20 were sedentary individuals. The subjects were equally allocated to four groups: group 1, zinc-supplemented sportsmen group; group 2, sportsmen group without supplementation; group 3, zinc-supplemented sedentary group; group 4, sedentary group without supplementation. Blood samples were collected from all subjects twice, once at the beginning of the study and once again at the end of 8-week procedures. The blood samples collected were analyzed to determine the levels of malondialdehyde (MDA), serum glutathione (GSH), serum glutathione peroxidase (GPx) activity, serum superoxide dismutase (SOD) activity (ELISA colorimetric method) and zinc (colorimetric method). No difference was found between MDA levels of the study groups in the beginning of the study. The highest MDA value at the end of the study was obtained in group 4 (p < 0.01). MDA levels in group 2 were established to be significantly higher than those in groups 1 and 3 (p < 0.01). GSH level, GPx, and SOD activities and zinc level measured in the beginning of the study were not different between groups. Measurements performed at the end of the study showed that groups 1 and 3 (zinc-supplemented groups) had the highest GSH level, GPx, and SOD activities and zinc level (p < 0.01). These parameters were not different in the groups without supplementation (groups 2 and 4). Results obtained at the end of the study indicate that zinc supplementation prevents production of free radicals by activating the antioxidant system. In conclusion, physiologic doses of zinc supplementation to athletes may beneficially contribute to their health and performance.