Effects of hyperthyroidism induced by L-thyroxin administration on lipid peroxidation in various rat tissues

Thyroid dysfunctions are associated with many pathological signs in the body. One of these is lipid peroxidation that develops due to over- or under-secretion of thyroid hormones. The present study was conducted to determine lipid peroxidation that develops in different tissues including the brain, liver and heart of rats in experimental hyperthyroidism induced by L-thyroxin. The study was carried out on 30 male Sprague-Dawley rats. They were divided into three groups as control, sham hyperthyroidism and hyperthyroidism. Malondialdehyde (MDA) and glutathione (GSH) levels in rat tissues were determined at the end of a 3-weeks period of L-thyroxin administration. It was observed that MDA levels in the hyperthyroidism group were significantly higher in the cerebral cortex, liver and ventriculer tissue of heart (p < 0.001) than in the control and in sham hyperthyroidism groups. GSH levels were higher in the hyperthyroidism group than in control and sham hyperthyroidism groups in all tissues (p < 0.001). Results demonstrate that hyperthyroidism induced by L-thyroxin activates both oxidant and antioxidant systems in cerebral, hepatic and cardiac tissues. However, the increase in antioxidant activity cannot adequately prevent oxidative damage.     

900 MHz pulse-modulated radiofrequency radiation induces oxidative stress on heart, lung, testis and liver tissues

Oxidative stress may affect many cellular and physiological processes including gene expression, cell growth, and cell death. In the recent study, we aimed to investigate whether 900 MHz pulse-modulated radiofrequency (RF) fields induce oxidative damage on lung, heart and liver tissues. We assessed oxidative damage by investigating lipid peroxidation (malondialdehyde, MDA), nitric oxide (NOx) and glutathione (GSH) levels which are the indicators of tissue toxicity. A total of 30 male Wistar albino rats were used in this study. Rats were divided randomly into three groups; control group (n = 10), sham group (device off, n = 10) and 900 MHz pulsed-modulated RF radiation group (n = 10). The RF rats were exposed to 900 MHz pulsed modulated RF radiation at a specific absorption rate (SAR) level of 1.20 W/kg 20 min/day for three weeks. MDA and NOx levels were increased significantly in liver, lung, testis and heart tissues of the exposed group compared to sham and control groups (p < 0.05). Conversely GSH levels were significantly lower in exposed rat tissues (p < 0.05). No significantly difference was observed between sham and control groups. Results of our study showed that pulse-modulated RF radiation causes oxidative injury in liver, lung, testis and heart tissues mediated by lipid peroxidation, increased level of NOx and suppression of antioxidant defense mechanism.     

Melatonin prevents oxidant damage in various tissues of rats with hyperthyroidism

Impairment of thyroid functions brings about pathological changes in different organs of body. Findings of in vivo and in vitro studies indicate that thyroid hormones have a considerable impact on oxidative stress. Melatonin reduces oxidative damage through its free radical eliminating and direct anti-oxidant effects. The present study was undertaken to determine how a 3-week period of intraperitoneal melatonin administration affected oxidative damage caused in experimental hyperthyroidism in rat. The experimental animals were divided into 3 groups (control, hyperthyroidism, hyperthyroidism+melatonin). Malondialdehyde (MDA) and glutathione (GSH) levels were determined in different tissues. MDA levels in cerebral, liver and cardiac tissues in hyperthyroidism group were significantly higher than those in control and hyperthyroidism+melatonin supplemented groups (p<0.001). The highest GSH levels were observed in the group that was administered melatonin in addition to having hyperthyroidism (p<0.001). These results show that hyperthyroidism increased oxidative damage in cerebral, hepatic and cardiac tissues of rat. Melatonin supplementation may also suppress oxidative damage.     

Lipid peroxidation in ovariectomized and pinealectomized rats: the effects of estradiol and progesterone supplementation

In the present study, we investigated the effect of estradiol and progesterone supplementation on oxidant and antioxidant parameters of renal tissue in ovariectomized and pinealectomized rats. The study was carried out on 36 adult, Sprague-Dawley strain female rats, 6 months of age and weighing 200-250 g. The rats were divided into six groups, each group included six rats: Group 1: Sham-ovariectomized (Sham-Ovx); Group 2: Ovariectomized (Ovx); Group 3: Ovx and estradiol (E) and progesterone (P) supplemented (Ovx+E-P); Group 4: Ovariectomized and sham pinealectomy (Ovx+sham Pnx); Group 5: Ovariectomized+Pinealectomized (Ovx+Pnx); Group 6: Ovariectomized+Pinealectomized+Hormone Supplemented group (Ovx+Pnx+E-P). The levels of malondialdehyde (MDA), reduced glutathione (GSH) and glutathione peroxidase (GSH-Px) were analysed in renal tissues of rats. The highest and the lowest levels of MDA were determined in Groups 5 and 1 respectively (p < 0.001). However, GSH and GSH-Px levels demonstrated statistically important decreases in groups 2, 4, 5 (p < 0.001). The findings of this study demonstrate that ovariectomy leads to oxidative damage in renal tissue. Pinealectomy in addition to ovariectomy greatly increases the oxidative damage. However, female sex hormones supplementations to the Ovx and/or Ovx+Pnx rats protected against lipid peroxidation by activating the antioxidant system.     

Protective effect of aminoguanidine against oxidative stress in an experimental peritoneal adhesion model in rats

Postoperative intraperitoneal adhesion formation is a major cause of intestinal obstruction, pain and infertility. This experimental study was designed to evaluate the degree of adhesion formation and peritoneal tissue levels of malondialdehyde (MDA), reduced glutathione (GSH) and total nitrite and nitrate (NO) and the effect of aminoguanidine (AG) on these metabolite values after postoperative intraperitoneal adhesion formation in rats. A total of 21 adult male Wistar albino rats were randomly divided into three groups. Control rats were untreated; the AG group received AG 200 mg kg(-1) i.p. for 10 consecutive days intraperitoneally after surgery. The sham group was given 0.9% NaCl. The rats were killed on postoperative day 10. The peritoneal tissues were harvested to determine the tissue levels of MDA, GSH, and NO activity. For light microscopic evaluation, the cecum was removed. Adhesion formation scores in the AG group were significantly lower than those of the control and sham groups (p < 0.017, p < 0.026 respectively). In the AG-treated rats, tissue levels of MDA and NO were significantly lower than in the control group (p < 0.017). The levels of GSH in aminoguanidine-treated rats were significantly higher than those of the control group (p < 0.01). The severity of the inflammation was more prominent in the control group compared with the AG-injected rats. The results demonstrate that in this experimental model, intraperitoneal administration of aminoguanidine decreases the incidence and extent of peritoneal adhesions and causes a decrease in MDA and NO and an increase in GSH values.     

Effects of melatonin on oxidative-antioxidative status of tissues in streptozotocin-induced diabetic rats

In view of the antioxidant properties of melatonin, the effects of melatonin on the oxidative-antioxidative status of tissues affected by diabetes, e.g. liver, heart and kidneys, were investigated in streptozotocin (STZ)-induced diabetic rats in the present study. Concentrations of malondialdehyde (MDA) and reduced glutathione (GSH), and activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in the tissues were compared in three groups of 10 rats each (control non-diabetic rats (group I), untreated diabetic rats (group II) and diabetic rats treated with melatonin (group III)). In the study groups, diabetes developed 3 days after intraperitoneal (i.p.) administration of a single 60 mg kg(-1) dose of STZ. Thereafter, while the rats in group II received no treatment, the rats in group III began to receive a 10 mg kg(-1) i.p. dose of melatonin per day. After 6 weeks, the rats in groups II and III had significantly lower body weights and higher blood glucose levels than the rats in group I (p < 0.001 and p < 0.001, respectively). MDA levels in the liver, kidney and heart of group II rats were higher than that of the control group (p < 0.01, p < 0.05, p < 0.01, respectively) and diabetic rats treated with melatonin (p < 0.05). The GSH, GSH-Px and SOD levels increased in diabetic rats. Treatment with melatonin changed them to near control values. Our results confirm that diabetes increases oxidative stress in many organs such as liver, kidney and heart and indicate the role of melatonin in combating the oxidative stress via its free radical-scavenging and antioxidant properties.     

Protective effect of melatonin against oxidative stress on adhesion formation in the rat cecum and uterine horn model

This experimental study was designed to evaluate the degree of adhesion formation and peritoneal tissue levels of malondialdehyde (MDA), reduced glutathione (GSH) and nitric oxide (NO) and the effect of melatonin on these metabolites in a postoperative intraperitoneal adhesion formation model in rats. Thirty adult female Wistar albino rats were subjected to standardized lesions by cecal and uterine horn abrasion and were randomly divided into three groups. Control rats were treated with 5% ethanol. Melatonin treated rats received 4 mg/kg melatonin before closure and for 10 consecutive days intraperitoneally after surgery. Rats in the sham operation group underwent a surgical procedure similar to the other groups however the peritoneal abrasion was not performed. On postoperative day 10 relaparatomy was performed. After the assessment of the adhesions, the rats in each group were sacrificed and peritoneal tissues were harvested to determine the tissue levels of MDA, GSH and NO activity. Adhesion formation scores in the melatonin group were significantly lower than that of control and sham group (p<0.01 and p<0.02, respectively). Tissue levels of MDA and NO were significantly lower in the melatonin treated rats when compared with control and sham groups. The levels of GSH in the melatonin treated rats were significantly higher than those of control and sham groups (p<0.01). The results demonstrate that in this experimental model, intraperitoneal administration of melatonin decreases the extent of peritoneal adhesions and causes a decrease in MDA and NO and an increase in GSH levels.     

Short-term thyroxine administration leads to lipid peroxidation in renal and testicular tissues of rats with hypothyroidism

Thyroid dysfunction brings about pathological changes in different organs of the body. The aim of the present study was to examine how experimental hypothyroidism and additional short-term high-dose thyroxine administration (one-week) affected lipid peroxidation in renal and testicular tissues of rats. The study was carried out on 30 male Spraque-Dawley rats. The experimental animals were divided into 3 groups as control, hypothyroidism and hypothyroidism + thyroxine administration. Both malondialdehyde (MDA) and glutathione (GSH) levels were lower in renal and testicular tissues of the hypothyroidism group than the control and hypothyroidism + thyroxine administration groups and the levels in hypothyroidism + thyroxine administration group were higher than those in the control and hypothyroidism groups (p < 0.001). Results of the study demonstrate that hypothyroidism reduced oxidant stress in kidney and testis tissues, but short-term, high-dose thyroxine administration in addition to hypothyroidism increased oxidant stress in the same tissues of rats.     

The effect of resveratrol on surgery-induced peritoneal adhesions in an experimental model

Adhesion formation is a common cause of complications following surgery. The aim of this study was to investigate the effect of resveratrol on intra-abdominal adhesion prevention in a rat model. Twenty one Wistar-Albino rats weighing 200-250 g were assigned to three groups, of 7 rats each. After a midline laparotomy was performed, a 1 cm area of the ceacum was abraded in two of the groups. They were then given either resveratrol (Group 1), or saline (Group 2) intraperitoneally. Group 3 rats (sham operation) received no treatment, without the serosal damage. On the 14th day, the rats were killed and the adhesion score was determined according to Mazuji's adhesion grade scale. The tissue levels of malondialdehyde (MDA), nitric oxide (NO), and reduced glutathione (GSH) were measured. The mean Mazuji's adhesion grade in the resveratrol group was 1.0 +/- 0.0, in the saline group 2.57 +/- 1.51, and zero in the sham operated group (p < 0.05 between the resveratrol group and saline group comparison). The levels of MDA and NO in the resveratrol group were significantly lower than those of the saline group (p < 0.001). The level of GSH in the resveratrol group was significantly higher than in the saline and sham operated groups (p < 0.001 and p < 0.001, respectively). Introduction of resveratrol into the peritoneal cavity at the time of surgery reduced adhesion formation effectively in this model. Resveratrol probably acts through reduction of lipid peroxidation products.     

Zinc prevention of electromagnetically induced damage to rat testicle and kidney tissues

The aim of this study was to investigate the extent of lipid peroxidation when zinc is administered to rats periodically exposed to a 50-Hz electromagnetic field for 5 min at a time over a period of 6 mo. Twenty-four Sprague-Dawley adult male rats were subdivided in groups of eight animals each. Group 1 served as untreated controls, group 2 was exposed to an electromagnetic field but received no additional treatment, and group 3 was exposed to electromagnetic radiation and treated with 3-mg/kg daily intraperitoneal injections of zinc sulfate. The erythrocyte glutathione activity (GSH) and the plasma, testicle, and kidney tissue levels of zinc (Zn) and of malondialdehyde (MDA) were measured in all of the animals. The plasma and testicle MDA levels in group 2 were higher than those in groups 1 and 3, with group 3 values significantly higher than those in group 1 (p<0.001). The kidney MDA levels in group 2 were higher than in groups 1 and 3 (p<0.001). The erythrocyte GSH level was lower in group 2 than in groups 1 and 3, with group 1 significantly lower than group 3 (p<0.001). In testicle and kidney tissues, the GSH levels in group 1 were lower than for groups 2 and 3, with group 2 significantly lower than group 3 (p<0.001) The plasma zinc levels were highest in group 3, followed by group 1 and group 2, which showed the lowest value (p<0.001). These results indicate that testicle and kidney tissue damage caused by periodic exposure to an electromagnetic field are ameliorated or prevented by zinc supplementation.     

Melatonin treatment protects against sepsis-induced functional and biochemical changes in rat ileum and urinary bladder

Sepsis is commonly associated with enhanced generation of reactive oxygen metabolites, which lead to multiple organ dysfunction. The aim of this study was to examine the role of melatonin, a potent antioxidant, in protecting the intestinal and bladder tissues against damage in a rat model of sepsis. Sepsis was induced by cecal ligation and perforation (CLP) in Wistar Albino rats. Sham operated (control) and CLP group received saline or melatonin (10 mg/kg, ip) 30 minutes prior to and 6 hours after the operation. Sixteen hours after the surgery, rats were decapitated and the intestinal and urinary bladder tissues were used for contractility studies, or stored for the measurement of malondialdehyde (MDA) content -an index of lipid peroxidation-, glutathione (GSH) levels -a key antioxidant- and myeloperoxidase (MPO) activity- an index of neutrophil infiltration-. Ileal and bladder MDA levels in the CLP group were significantly increased (p < 0.001) with concomitant decreases in GSH levels (p < 0.01 - p < 0.001) when compared to the control group. Similarly, MPO activity was significantly increased (p < 0.001) in both ileum and bladder tissues. On the other hand, melatonin treatment significantly reversed (p < 0.001) the elevations in MDA and MPO levels, while reduced GSH levels were increased back to the control levels (p < 0.01 - p < 0.001). In the CLP group, the contractility of the ileal and bladder tissues decreased significantly compared with controls. Melatonin treatment of the CLP group restored these responses. In this study, CLP induced dysfunction of the ileal and bladder tissue of rats was reversed by melatonin treatment. Moreover, melatonin, as an antioxidant, abolished the elevation in lipid peroxidation products and myeloperoxidase activity, and reduction in the endogenous antioxidant glutathione and thus protected the tissues against sepsis-induced oxidative damage.     

The effects of isosorbide dinitrate on methemoglobin reductase enzyme activity and antioxidant states

Isosorbide dinitrate (ISDN) has been used in the treatment of ischaemic cardiovascular diseases for many years. ISDN is the most popular nitric oxide donor and causes methemoglobinemia as an important side-effect. The purpose of this study was to examine antioxidant states and methemoglobin reductase activity after giving ISDN and ISDN plus vitamin E. Rats were divided into three groups according to the treatment: control group, ISDN group and ISDN plus vit. E group. We measured reduced glutathione in blood (GSH), plasma malondialdehyde (MDA), erythrocyte superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and NADH-dependent methemoglobin reductase activities. In the ISDN group, plasma MDA levels were significantly high compared to the control and ISDN + vit. E groups (p < 0.001). In the ISDN and ISDN + vit. E groups, blood GSH levels were higher than those of the control group (p < 0.05). Changes of SOD and GPx activities were not significant. In the ISDN and ISDN + vit. E groups the erythrocyte catalase and NADH-dependent methemoglobin reductase activities were significantly higher than that in the control group (p < 0.001). We conclude that oxidant drugs such as ISDN need to be carefully used because of lipid peroxidation and methemoglobinemia. These findings support the notion that vitamine E protects tissues against oxidative stress.     

Evaluation of trace elements and oxidative stress levels in the liver and kidney of streptozotocin-induced experimental diabetic rat model

In this study, we aimed to investigate the relationship among trace elements (Cu, Fe, Zn and Mg) on oxidative and anti-oxidative substances in liver and kidneys tissues in streptozotocin (STZ) diabetic rat model. The mean levels of Fe and Cu were found significantly higher in the liver and kidneys of the diabetic rats, in comparison to the control rats. On the other hand, the mean levels of Zn and Mg in the liver and kidneys of the diabetic rats were significantly lower than in the control rats. The liver and kidneys malonaldehyde (MDA) levels of the experimental group were found to be higher than in the control group (p < 0.001; p < 0.01, respectively) after 4 weeks of the experimental period. Superoxide dismutase (SOD) activities and glutathione (GSH) levels in the liver tissue of STZ-induced diabetic rats were found to be lower in the experimental group than in the control group (p < 0.01). SOD activity and GSH concentration in kidneys of the diabetic rats were significantly diminished with respect to the control group (p < 0.01). In conclusion, the present results indicate that the increase of Fe and Cu together with decreas of Zn and Mg concentration in liver and kidney of STZ-induced diabetic rats may be involved in disturbances of oxidative balance in both the tissues. Therefore, these findings may contribute to explain the role of impaired ion metabolism of some elements in the progression of diabetic oxidative complications.     

The effect of thyroxine administration on lipid peroxidation in different tissues of rats with hypothyroidism

Thyroid dysfunctions bring about pathological changes in different organs of the body. Findings obtained from in vivo and in vitro studies point out that thyroid hormones have a strong impact on oxidative stress. The present study was conducted to demonstrate how high-dose thyroxin administration for one week affected oxidative damage formed in experimental hypothyroidism. The study was carried out with 30 Spraque-Dawley species male rats. The experimental animals were divided into 3 groups (Group 1, control; Group 2, hypothyroidism; Group 3, hypothyroidism + thyroxine administration). Malondialdehyde (MDA) and glutathione (GSH) levels were determined in cerebral, hepatic and cardiac tissues after the experimental period. MDA and GSH levels in cerebral, hepatic and cardiac tissues of hypothyroidism + thyroxine supplemented group were higher than those in the control and hypothyroidism groups (p<0.001). The same parameters were higher in the control group than those in the hypothyroidism group (p<0.001). The results of the present study show that hypothyroidism reduced the oxidative damage in cerebral, hepatic and cardiac tissues of rats. However, high-dose thyroxine administration in addition to induced hypothyroidism increased oxidative damage in the same tissues and that this damage could not be prevented despite the increase in the antioxidant system activity.     

Ethanol-induced hepatotoxicity and protective effect of betaine.

The protective effects of betaine in ethanol hepatotoxicity were investigated in 24 female wistar albino rats. Animals were divided into three groups: control, ethanol and ethanol + betaine group. Animals were fed liquid diets and consumed approximately 60 diet per day. Rats were fed ethanol 8 kg(- 1) day(- 1). The ethanol + betaine group were fed ethanol plus betaine (0.5% w/v). All animal were fed for 2 months. Reduced glutathione, malondialdehyde and vitamin A were determined in the liver tissue. Alanine aminotransferase activities were also measured on intracardiac blood samples. GSH levels in the ethanol group were significantly lower than these in the control group (p < 0.001). GSH was elevated in the betaine group as compared to the ethanol group (p < 0.001). MDA in the ethanol group was significantly higher than that in the control group (p < 0.05). MDA was decreased in the betaine group as compared to the ethanol group (p < 0.05). Vitamin A in the ethanol group was significantly lower than that in the control group (p < 0.01), but, in the ethanol + betaine group it was high compared with the ethanol group (p < 0.01). ALT in the ethanol group was higher than that in the control group (p < 0.05). Oxidative stress may play a major role in the ethanol-mediated hepatotoxicity. Betaine may protect liver against injury and it may prevent vitamin A depletion. Therefore, it may be a useful nutritional agent in the prevention of clinical problems dependent on ethanol-induced vitamin A depletion and peroxidative injury in liver.     

17β-Estradiol and Vitamin E Modulates Oxidative Stress-Induced Kidney Toxicity in Diabetic Ovariectomized Rat

The aim of this study was to investigate the effects of vitamin E (alpha-tocopherol) and 17β-estradiol (E(2)) supplementation on malondialdehyde (MDA), glutathione (GSH), vitamin A, beta carotene, selenium-dependent glutathione peroxidase (GSH-Px), zinc-dependent superoxide dismutase (SOD), and copper/zinc-dependent catalase (CAT) values in the kidney of ovariectomized (OVX) diabetic rats. Forty-two female rats were randomly divided into seven equal groups as follows: group I, control; group II, OVX; group III, OVX+E(2); group IV, OVX+E(2)+alpha-tocopherol; group V, OVX+diabetic; group VI, OVX+diabetic+E(2); and group VII, OVX+diabetic+E(2)+alpha-tocopherol. E(2) (40?μg?kg(-1)/day) and alpha-tocopherol (100?μg?kg(-1)/day) were given. Bilateral ovariectomy was performed in all groups except group I. After 4?weeks, antioxidant and MDA levels in the kidney for all groups were analyzed. GSH-Px, CAT, SOD, GSH levels, vitamin A, and beta carotene levels were decreased in OVX group compared to those in the control group but MDA level was elevated via ovariectomy. However, E(2) and E(2)+alpha-tocopherol supplementations in OVX group was associated with an increase in the GSH-Px, GSH, CAT and Zn-SOD values, vitamin A, and beta carotene levels but a decrease in MDA levels in kidney. The MDA levels in the kidney of diabetic OVX rats were found higher than those in the control and OVX groups. However, GSH, GSH-Px, CAT, SOD, vitamin A, and beta carotene levels in kidney were lower in OVX diabetic rats. On the other hand, E(2) and E(2)+alpha-tocopherol supplementations to OVX diabetic rats have caused an increase in GSH-Px, CAT and SOD, GSH, vitamin A, and beta carotene levels but a decrease in MDA levels. In conclusion, the E(2) and E(2)+alpha-tocopherol supplementations to diabetic OVX and OVX rats may strengthen the antioxidant defense system by reducing lipid peroxidation, and therefore they may play a role in preventing renal disorders.     

Cardioprotection from ischemia and reperfusion injury by Withania somnifera: a hemodynamic, biochemical and histopathological assessment

The efficacy of Withania somnifera (Ws) to limit myocardial injury after ischemia and reperfusion was explored and compared to that of Vit E, a reference standard known to reduce mortality and infarct size due to myocardial infarction. Wistar rats (150-200 g) were divided into six groups and received orally saline (sham, control group), Ws-50/kg (Ws control and treated group) and Vit E-100 mg/kg (Vit E control and treated group) respectively for 1 month. On the 31st day, rats of the control, Vit E and Ws treated groups were anesthetized and subjected to 45 min occlusion of the LAD coronary artery followed by 60 min reperfusion. Hemodynamic parameters: systolic, diastolic and mean arterial pressure (SAP, DAP, MAP), heart rate (HR), left ventricular end diastolic pressure (LVEDP), left ventricular peak (+)LVdP/dt and (-)LVdP/dt were monitored. Hearts were removed and processed for histopathological and biochemical studies: Myocardial enzyme viz, creatin phosphokinase (CPK), and antioxidant parameters: malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSHPx) were estimated. Postischemic reperfusion produced significant cardiac necrosis, depression of left ventricular functions (MAP, LVEDP, (+) and (-)LVdP/dt) and a significant fall in GSH (p < 0.01), SOD, CAT (p < 0.05), LDH and CPK (p < 0.01) as well as an increase in MDA level (p < 0.05) in the control group rats as compared to sham group. The changes in levels of protein and GPx was however, not significant. Ws and Vit E favorably modulated most of the hemodynamic, biochemical and histopathological parameters though no significant restoration in GSH, MAP (with Vit E) were observed. Ws on chronic administration markedly augmented antioxidants (GSH, GSHPx, SOD, CAT) while Vit E did not stimulate the synthesis of endogenous antioxidants compared to sham. Results indicate that Ws significantly reduced myocardial injury and emphasize the beneficial action of Ws as a cardioprotective agent.     

Protective effect of alpha-tocopherol on oxidative stress in experimental pulmonary fibrosis in rats

The study was undertaken to investigate the influence of alpha-tocopherol (vitamin E) on malondialdehyde (MDA) and glutathione (GSH) levels and catalase (CAT) activity in lung of rats with bleomycin-induced pulmonary fibrosis (PF). Fourteen Wistar-albino rats were randomly divided into two groups of seven animals each. The first group was treated intra-tracheally with bleomycin hydrochloride (BM group); the second group was also instilled with BM but received injections of alpha-tocopherol twice a week (BM + E group). The third group was treated in the same manner with saline solution only, acting as controls (C). There were decreases in GSH level and CAT activity while an increase in MDA level in BM group was found compared to the control group (p < 0.05). Vitamin E had a regulator effect on these parameters. After administration of alpha-tocopherol, the increase in GSH level and CAT activity and the decrease in MDA level were seen in BM + E group compared to BM group (p < 0.05). Distinct histopathological changes were found in the BM group compared to the untreated rats. Less severe fibrotic lesions were also observed in the BM + E group. The results show that vitamin E is effective on the prevention of BM-induced PF, as indicated by differences in the lung levels of oxidants and antioxidants.     

维生素C对镉负荷小鼠睾丸抗氧化功能的影响*

目的: 分析镉(Cd)负荷不同时间对小鼠睾丸抗氧化酶的影响及维生素C(VC)的保护作用。方法: 清洁级雄性昆明小鼠72只分为4组(n=18):对照组、Cd组(CdCl₂ 3 mg/kg)、VC组(200 mg/kg)、VC(200 mg/kg)+ Cd(CdCl₂ 3 mg/kg)组,每日染毒1次,染毒1 d和3 d及同时补充VC保护,第1日和第3日染毒24 h后,每组取半数小鼠称重,取血清和睾丸组织;检测睾丸脏器系数,血清和睾丸组织丙二醛(MDA)、超氧化物歧化酶(SOD),及睾丸组织谷胱甘肽过氧化物酶(GSH-Px)、还原型谷胱甘肽(GSH)、氧化型谷胱甘肽(GSSG)及总谷胱甘肽(T-GSH)。结果: 与对照组比较,Cd组1 d和3 d小鼠体重和睾丸脏器系数下降;染毒3 d,Cd组小鼠血清SOD显著降低、MDA显著升高(P＜0.05);Cd组1 d小鼠睾丸的SOD、GSH-Px、T-GSH及GSH/GSSG显著升高(P＜0.05),而3 d的上述指标均显著降低(P＜0.05),Cd组1 d和3 d MDA水平均显著升高(P＜0.05);VC处理后减轻的程度有所降低。与Cd组比较,VC+ Cd组血清SOD和MDA水平在染毒3 d变化有显著性差异(P＜0.05);VC+ Cd组在染毒1 d和3 d,小鼠睾丸的SOD、GSH-Px、T-GSH及GSH/GSSG水平变化有显著性差异(P＜0.05),VC+ Cd组在染毒3 d睾丸的MDA水平显著降低(P＜0.05)。与Cd组1 d比较,染毒3 d小鼠的血清SOD水平显著降低(P＜0.05),睾丸指标变化也有显著性差异(P＜0.05)。结论: VC处理可在一定程度上改善镉负荷小鼠的抗氧化功能,对睾丸氧化损伤具有保护作用。     

Methionine challenge paradoxically induces a greater activation of the antioxidant defence in subjects with hyper- vs. normohomocysteinemia

To determine whether hyperhomocysteinemia induced post-methionine loading (PML) is associated with different response in the aminothiol redox state and oxidative stress vs. normohomocysteinemia, we assessed PML plasma thiols, vitamins, free malondialdehyde (MDA), and blood reduced glutathione (GSH) in 120 consecutive subjects (50 [35-56] years, 83 males), divided into two groups according to PML plasma total Hcy < 35 microM (Group 1, n = 65) or > or = 35 microM (Group 2, n = 55).In the group as a whole, plasma reduced cysteine and cysteinylglycine, blood reduced GSH (all p for time = 0.0001) and plasma total GSH (p for time = 0.001) increased from baseline to PML. MDA values were unchanged. Group 1 and 2 differed in blood reduced GSH (p for group = 0.004, higher in Group 2), and MDA levels (p for group = 0.024, lower in Group 2).The oxidative stress induced by methionine challenge seems to be opposed by scavenger molecules activation, namely GSH, and lipid peroxidation does not increase. This mechanism paradoxically appears to be more efficient in hyperhomocysteinemic subjects.