Monthly variations in ovine seminal plasma proteins analyzed by two-dimensional polyacrylamide gel electrophoresis

This study was conducted to evaluate monthly changes in the ram seminal plasma protein profile using two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) with a polyacrylamide linear gradient gel. Likewise, comparative analyses of the protein composition of ovine seminal plasma (SP) from ejaculates obtained along the year, and its relationship with sperm motility, viability and concentration of ejaculate were carried out. Western-blot analysis was performed to specifically detect P14, a ram SP protein postulated to be involved in sperm capacitation and gamete interaction [Barrios B, Fernández-Juan M, Mui?o-Blanco T, Cebrián-Pérez JA. Immunocytochemical localization and biochemical characterization of two seminal plasma proteins which protect ram spermatozoa against cold-shock. J Androl 2005;26:539-49], and its variations along the year have also been established. The experiment was carried out from May 2003 to April 2004, with nine Rasa Aragonesa rams. Ejaculates obtained every 2 days were pooled and used for each assay, to avoid individual differences, and three two-dimensional SDS-PAGE gels were run for each month. The high resolution of the gradient gel allowed the image analysis software to detect around 252 protein spots, with pIs ranging from 4.2 to 7.6, and molecular weight (M(r)) from 12.5 to 83.9 kDa. Four protein spots (1, 2, 3 and 4) of low M(r) (15.1, 15.7, 15.9 and 21.0 kDa) and acidic pI (5.9, 5.3, 5.7 and 6.6), respectively, had the highest relative intensity in the SP map (11.2, 9.3, 4.7 and 7.7%, respectively). Spot 3 was more abundant (P<0.05) from May to December, and negatively correlated (P<0.05, r=-0.34) with sperm viability and concentration (P<0.05, r=0.36). Another 12 protein spots also had significant quantitative differences (P<0.05) along the year, and 17 protein spots, which correlated with some seminal quality parameter, did not show quantitative monthly changes. Western-blot analysis indicated that spots 1 and 2 reacted with the anti-P14 antibody, raised against the P14 band (approximate M(r) 14 kDa) of ram SP. This indicates that spots 1 and 2 are similar to RSP15 [Bergeron A, Villemure M, Lazure C, Manjunath P. Isolation and characterization of the major proteins of ram seminal plasma. Mol Reprod Dev 2005;71:461-70], bovine PDC-109 [Esch FS, Ling NC, Bohlen P, Ying S, Guillemin R. Primary structure of PDC-109, a major protein constituent of bovine seminal plasma. Biochem Biophys Res Commun 1983;113:861-7] (also called BSP A1/A2 [Manjunath P, Sairam MR. Purification and biochemical characterization of three major acidic proteins (BSP-A1, BSP-A2 and BSP-A3) from bovine seminal plasma. Biochem J 1987;241:685-92]) and goat GSP-14/15 kDa [Villemure M, Lazure C, Manjunath P. Isolation and characterization of gelatine-binding proteins from goat seminal plasma. Reprod Biol Endocrinol 2003;1:39], based on our previous results on the P14 amino acid sequence [Barrios B, Fernández-Juan M, Mui?o-Blanco T, Cebrián-Pérez JA. Immunocytochemical localization and biochemical characterization of two seminal plasma proteins which protect ram spermatozoa against cold-shock. J Androl 2005;26:539-49].     

Scavenger Enzyme Activities in Subcellular Fractions of White Clover (Trifolium repens L.) under PEG-induced Water Stress

Scavenger enzyme activities in subcellular fractions under polyethylene glycol (PEG)-induced water stress in white clover (Trifolium repens L.) were studied. Water stress decreased ascorbic acid (AA) content and catalase (CAT) activity and increased the contents of hydrogen peroxide (H₂O₂), thiobarbituric acid reactive substances (TBARS) (measure of lipid peroxidation), and activities of superoxide dismutase (SOD), its various isozymes, ascorbate peroxidase (APOX), and glutathione reductase (GR) in cellular cytosol, chloroplasts, mitochondria, and peroxisomes of Trifolium repens leaves. In both the PEG-treated plants and the control, chloroplastic fractions showed the highest total SOD, APOX, and GR activities, followed by mitochondrial fractions in the case of total SOD and GR activities, whereas cytosolic fractions had the second greatest APOX activity. However, CAT activity was the highest in peroxisomes, followed by the cytosol, mitochondria, and chloroplasts in decreasing order. Although Mn-SOD activity was highest in mitochondrial fractions, residual activity was also observed in cytosolic fractions. Cu/Zn-SOD and Fe-SOD were observed in all subcellular fractions; however, the activities were the highest in chloroplastic fractions for both isoforms. Total Cu/Zn-SOD activity, the sum of activities observed in all fractions, was higher than other SOD isoforms. These results suggest that cytosolic and chloroplastic APOX, chloroplastic and mitochondrial GR, mitochondrial Mn-SOD, cytosolic and chloroplastic Cu/Zn-SOD, and chloroplastic Fe-SOD are the major scavenger enzymes, whereas cellular CAT may play a minor role in scavenging of O₂⁻ and H₂O₂ produced under PEG-induced water stress in Trifolium repens.     

Tri-iodo thyronine regulates antioxidant enzyme activities in different cell fractions through a mechanism sensitive to actinomycin D in a teleost, Anabas testudineus (Bloch)

The present study evaluated the effects of hyperthyroid state on lipid peroxidation and antioxidant enzymes in the crude (CF), post nuclear (PNF) and mitochondrial fractions (MF) of the fish liver. The in vivo injection of T3 (200ng) did not change the lipid peroxidation products, malondialdehyde (MDA) and conjugated dienes (CD), while actinomycin D (10microg), a potent mRNA inhibitor when administered with T3 increased them. The antioxidant enzymes like superoxide dismutase (SOD) and catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) had an increased activity in CF and MF of hyperthyroid group to compete the increased oxidative stress, but actinomycin D partially inhibited the T3-induced activity. SOD and CAT activities in PNF of hyperthyroid group had no change, the glutathione concentration varied depending on the GPx and GR activity. Hyperthyroidism decreased the protein content, while simultaneous administration of actinomycin D inhibited the T3 action of elevating the protein content. The results suggest that the antioxidant defense status in A. testudineus is modulated by thyroid hormone, through an action sensitive to actinomycin D.     

Parameters related to oxygen free radicals in erythrocytes,plasma and epidermis of the hairless rat

The following parameters related to oxygen free radicals (OFR) were determined in erythrocytes and the epidermis of hairless rats: catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), reduced (GSH) and oxidized (GSSG) glutathione, glutathione S-transferase (GST), superoxide dismutase (SOD) and thiobarbituric acid reactive substances (TBARS). GSH, GSSG and TBARS were also analyzed in plasma. In erythrocytes, the Pearson correlation coefficients (r) were significant (p < 0.001) between glutathione and other parameters as follows: GSH correlated negatively with GSSG (r = -0.665) and TBARS (r = -0.669); GSSG correlated positively with SOD (r = 0.709) and TBARS (r = 0.752). Plasma GSSG correlated negatively with erythrocytic thermostable GST activity (r = -0.608; p=0.001) and with erythrocytic total GST activity (r = -0.677; p < 0.001). In epidermis (p < 0.001 in all cases), GSH content correlated with GSSG (r = 0.682) and with GPx (r = 0.663); GSSG correlated with GPx (r = 0.731) and with GR (r = 0.794). By multiple linear regression analysis some predictor variables (R(2)) were found: in erythrocytes, thermostable GST was predicted by total GST activity and GSSG, GSSG content was predicted by GSH and by the GSH/GSSG ratio and GPx activity was predicted by GST, CAT and SOD activities; in epidermis, GSSG was predicted by GR and SOD activities and GR was predicted by GSSG, TBARS and GPx. It is concluded that the hairless rat is a good model for studying OFR-related parameters simultaneously in blood and skin, and that it may provide valuable information about other animals under oxidative stress.     

Seasonal changes in antioxidant defence system of liver and gills of Salmo trutta caspius, Salmo trutta labrax and Salmo trutta macrostigma

Seasonal changes in antioxidant enzyme activities (superoxide dismutase, SOD, EC 1.15.1.1; catalase, CAT, EC 1.11.1.16; glutathione peroxidase, GPx, EC 1.11.1.9; glutathione reductase, GR, EC 1.6.4.2; glucose-6-phosphate dehydrogenase, G6PD, EC 1.1.1.49 and glutathione S -transferase, GST, EC 1.5.1.18) and lipid peroxidation (LPO) levels of livers and gills of female Caspian trout Salmo trutta caspius , Black Sea trout Salmo trutta labrax and mountain trout Salmo trutta macrostigma were investigated. SOD, CAT, GPx, G6PD and GST activities were higher in liver compared to gills of all sub-species; concomitantly, the GR activity was also higher in the livers of S. t. caspius and S. t. labrax , but the reverse was seen in S. t. macrostigma . LPO levels were higher in the gills compared to the liver of all sub-species. There was no general trend in the seasonal changes in the gill antioxidant enzyme (AE) activities or LPO levels. Higher AE activities, however, were found in the liver of each sub-species during autumn, and this coincided with an increase in the gonado-somatic index.     

Total and specific activities of superoxide dismutase (SOD) in seminal plasma are related with the cryotolerance of jackass spermatozoa

This study investigated whether the activities of four antioxidant enzymes present in jackass seminal plasma (SP), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) and glutathione reductase (GSR), are related to the sperm ability to withstand cryopreservation. Eighteen ejaculates from 16 healthy jackasses were collected and split into two aliquots. The first one was centrifuged (3,000×g, 4 °C for 10 min) and used to determine the activities of these four enzymes in SP, whereas the other was diluted in a skim-milk extender and then cryopreserved. Assessment of sperm motility and membrane integrity was performed before and after cryopreservation. Based on the percentages of total motile and viable spermatozoa at post-thaw, samples were classified as good (GFE) or poor (PFE) freezability ejaculates through cluster analyses. Total and specific activities of SOD in seminal plasma were higher (P < 0.05) in GFE than in PFE, whereas no significant differences between GFE and PFE were observed regarding total and specific activities of CAT, GPX and GSR. However, post-thaw sperm parameters were positively correlated with total and specific activities of CAT and negatively correlated with those of GSR. In conclusion, determination of total and specific activities of SOD in the seminal plasma of a given jackass ejaculate may predict the sperm ability to withstand cryopreservation. In addition, our results warrant further research on addressing whether SOD activity in seminal plasma does not only allow predicting the sperm cryotolerance of a given ejaculate but also that of all ejaculates from a given jackass.     

Antioxidative stress proteins and their gene expression in brown trout (Salmo trutta) from three rivers with different heavy metal levels

Three populations of brown trout (Salmo trutta) exposed to different metal levels in their natural environments, were studied with respect to antioxidants metallothionein (MT), superoxide dismutase (SOD) and catalase (CAT) as well as for corresponding mRNA levels. In addition, mRNA levels were studied for glutathione peroxidase (GPx) and glutathione reductase (GR). The Cd/Zn-exposed trout (Naustebekken River) had higher accumulated levels of Cd, Cu and Zn in gills, and higher levels of MT (both protein and mRNA) in liver and kidney as well as in gills compared to the Cu-exposed trout (Rugla River) and trout from an uncontaminated reference river (Stribekken River). Less MT found in the Cu-exposed trout may increase susceptibility to oxidative stress, but no higher levels of antioxidant mRNAs were found in gills of these trouts. The data indicated that chronic exposures of brown trout to Cd, Zn and/or Cu did not involve maintenance of high activities of SOD and CAT enzymes in gills, although SOD mRNA levels were higher in the Cd/Zn-exposed trout. In livers, mRNA levels of SOD, CAT and GPx were higher in the metal-exposed trout, but in the case of GR this was only seen in kidneys of Cd/Zn-exposed trout. However, both metal-exposed groups had higher activities of SOD enzyme in liver compared to the unexposed reference trout, and CAT activity was found to be higher in kidneys of Cu-exposed trout. The Cu-exposed trout did not seem to rely on MT production to avoid Cu toxicity in gills, but rather by keeping the Cu uptake at a low level. A coordinated expression of different stress genes may also be important in chronic metal exposure. It may be concluded that the observed metal effects relies on acclimation rather than on genetic adaptation in the metal exposed populations.     

Benfotiamine Enhances Antioxidant Defenses and Protects against Cisplatin‐Induced DNA Damage in Nephrotoxic Rats

The objective of the present study was to assess superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), paraoxonase (PON1), glutathione reductase (GR), and catalase (CAT) activities ratio and their relationship with DNA oxidative damage in rats treated with cisplatin (3 mg/kg bwt/day) in the presence and absence of benfotiamine (100 mg/kg/day) for 25 days. Cisplatin‐induced renal damage was evidenced by renal dysfunction and elevated oxidative stress markers. SOD activity and levels of nitric oxide, protein carbonyl, malondialdehyde, and 8‐hydroxy‐2'‐deoxyguanosine were significantly increased by cisplatin treatment. Moreover, the ratios of GPx/GR, SOD/GPx, SOD/CAT, and SOD/PON1 were significantly increased compared to control. In contrast, glutathione levels were significantly decreased by cisplatin treatment. Simultaneous treatment of rats with cisplatin and benfotiamine ameliorate these variables to values near to those of control rats. This study suggests that benfotiamine can prevent cisplatin‐induced nephrotoxicity by inhibiting formation reactive species of oxygen and nitrogen. © 2013 Wiley Periodicals, Inc. J BiochemMol Toxicol 27:398‐405, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/jbt.21501     

Evaluation of gender-related differences in various oxidative stress enzymes in mice

Oxidative stress caused by redundant free radical, lipid oxygen and peroxide usually results in the pathogenesis of various diseases, which can be alleviated by cellular antioxidant enzymes. According to statistics, there are different incidence rates of some diseases depending on the gender. The present study aimed to investigate potential gender-related differences of antioxidant enzymes in mice. The activities of glutamate-cysteine ligase (GCL), glutathione reductase (GR), glutathione peroxidase (GPx), glutathione S-transferase (GST), superoxide dismutase (SOD) and catalase (CAT) in the kidney, brain, lung and heart of both male and female mice were determined. Our results showed that GPx and GCL activities were higher in female kidney and brain than those in male. On the other hand, the activities of SOD were higher in female brain and lung than those in male. Moreover, female kidney appeared to show higher activities of CAT than the male kidney. But the activities of GCL and GPx were higher in male heart than those in female. Taken together, our results demonstrate that there are gender-related differences in the activities of cellular antioxidant enzymes in various important organs in mice. Variations in such enzymes may be the explanation for some gender-related diseases.     

Aminoguanidine prevented impairment of blood antioxidant system in insulin-dependent diabetic rats

Non-enzymatic glycation is implicated in the development of various diseases such as Alzheimer's and diabetes mellitus. However, it is also observed during the physiologic process of aging. There is considerable interest in the contribution of oxidative stress to diabetes mellitus. An increase in the generation of reactive oxygen species can occur by non-enzymatic glycation and glucose autoxidation. Both of these processes lead to the formation of AGEs (Advanced glycation end-products) that contribute to the irreversible modification of enzymes, proteins, lipids and DNA. In this study, the effect of chronic hyperglycemia on the antioxidant system of diabetic rats was evaluated. The working hypothesis is that the loss of glucose homeostasis reduces the capacity to respond to oxidative damage. The enzymatic activities of CAT (catalase), GPx (gluthatione peroxidase), GR (gluthatione reductase) and GSH (reduced gluthatione) were increased in the blood of healthy rats subjected to endurance training, whereas, in diabetic rats the activities of CAT, GPx and GR were unaltered by similar training. SOD showed low activity in endurance-trained rats. The administration of aminoguanidine (an inhibitor of glycation reactions) in the drinking water increased the activities of CAT, GPx and GR, suggesting that glycation may be responsible for the partial inactivation of these enzymes. These results indicate that the association of hyperglycemia with strenuous physical exercise may induce cellular damage by impairing the antioxidant defense system.     

Effects of Cadmium on Antioxidant Enzyme Activities in Sugar Cane

Sugar cane (Saccharum officinarum L. cv. Copersucar SP80-3280) seedlings were grown in nutrient solution with varying concentrations (0, 2 and 5 mM) of cadmium chloride for 96 h. Leaves were analysed for catalase (CAT), glutathione reductase (GR) and superoxide dismutase (SOD) activities. Although a clear effect of CdCl₂ on plant growth was observed, the activity of SOD was not altered significantly. However, the CAT activity decreased as the concentration of CdCl₂ increased. GR exhibits a significant increase in activity at 2 and 5 mM CdCl₂. CAT and SOD isoenzymes were further characterised by analysis in non-denaturing PAGE. Activity staining for SOD revealed up to seven isoenzymes in untreated control and 2 mM CdCl₂ treated plants, corresponding to Cu/Zn-SOD isoenzymes. At 5 mM CdCl₂, only six Cu/Zn-SOD isoenzymes were observed. No Fe-SOD and Mn-SOD isoenzymes were detected. For CAT, one band of activity was observed.     

Maternal cadmium intoxication: effects on fetal brain antioxidant defense parameters

Summary

The antioxidant potential of the brain in developing fetuses was assessed at gestational days (GD) 16, 18 and 20 and postnatal day (PND)1. Higher activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) were noticed during fetal development which were reduced to about half and one-quarter, respectively, at PND 1. Glutathione reductase (GR) activity remained stationary throughout the experiment and the values were very high compared to those reported for weanling rats. In contrast, catalase (CAT) activity increased with development. Glutathione (GSH) and total sulfhydryls (TSH) were maximum in 16-day fetal brains and declined subsequently. Brain lipid peroxidation (LPO) was found to increase with age. A group of animals was exposed to 20 ppm cadmium (Cd) in drinking water from the day of conception up to PND 1. Cd was found to increase the activities of brain SOD, CAT, and GR significantly at all the time intervals. The metal exposure decreased fetal brain GPx at GD 18 and 20, whereas GPx activity declined precipitously in both groups on PND 1. Cd caused both increments and decrements in the GSH and TSH levels (depending on gestational day) and increased the LPO in brain. It may be concluded that the Cd-intoxicated fetal brain undergoes significant changes in antioxidant defense parameters which, overall, may be sufficient to permit near-normal development and prevent substantial oxidant damage.     

Acute phase immune response to exercise coexists with decreased neutrophil antioxidant enzyme defences

Long-duration or damaging exercise initiates reactions that resemble the acute phase response to infection and induces neutrophil priming for oxidative activity. Our objective was to establish the status of the antioxidant defences and of the oxidative equilibrium in the neutrophils of sportsmen prior to and after intense physical exercise. Nine voluntary male professional cyclists participated in this study. The exercise was a cycling mountain stage (171 km) and the cyclists took a mean ±SEM of 270 ±12 min to complete it. We determined the activities of catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx), the levels and activity of superoxide dismutase (SOD), the concentrations of ascorbate, glutathione and glutathione disulphide (GSSG) and DNA levels in neutrophils. The cycling stage decreased enzyme activities expressed per DNA units: CAT (33%), SOD (38%), GPx (65%); increased ascorbate concentration in neutrophils and decreased the GSH/GSSG ratio and the enzyme activities expressed per DNA units. Neutrophils could contribute to plasma antioxidant defences against oxidative stress induced by exercise because they probably provide antioxidant enzymes and ascorbate.     

Nasturtium officinale reduces oxidative stress and enhances antioxidant capacity in hypercholesterolaemic rats

Nasturtium officinale R. Br. (Brassicaceae) has been used as a home remedy by the people of south eastern (SE) region of Iran as a medicinal plant. This therapeutical application has been attributed to Nasturtium officinale (N. officinale) antioxidant capacity which is mostly tested by means of cell-free assays: 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP). In addition, the antioxidant effect of N. officinale extract has been investigated in hypercholesterolaemic rats in vivo. The results revealed that the extract has notable scavenging activity against DPPH radicals as well as potent reducing power in FRAP assay. Intragastric administration of N. officinale (500 mg/kg body weight per day) to groups of hypercholesterolaemic rats for 30 days lowered their blood total cholesterol (TC), triglyceride (TG), and low density lipoprotein cholesterol (LDL-C) levels by 37, 44 and 48%, respectively. However, the blood high density lipoprotein cholesterol (HDL-C) levels in the same treated rats increased by 16%. To evaluate the mechanism(s) of action, we studied the antioxidative potential of N. officinale extract in terms of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GR) activities and also the level of reduced glutathione (GSH) in the liver tissues. In addition, hepatic tissue malondialdehyde level (MDA, an index of lipid peroxidation) was also determined. Under hypercholesterolaemic condition, hepatic MDA was increased. Moreover, our data indicated GSH depletion along with significant reduction in the activities of CAT and SOD in rats fed high-fat diet rats. On the other hand, significant elevation in the activities of GPx and GR were seen in the same group of rats. Treatment of hypercholesterolaemic rats with N. officinale extract significantly increased the GSH level along with enhanced CAT and SOD activities in liver tissues. Furthermore, N. officinale extract significantly decreased hepatic MDA as well as GPx and GR activities in plant-treated rats. Based on our data, it can be concluded that N. officinale has a high hypolipidaemic activity and this may be attributed to its antioxidative potential.     

Protective effect of resveratrol and vitamin E against ethanol-induced oxidative damage in mice: biochemical and immunological basis

The metabolism of ethanol gives rise to the generation of excess amounts of reactive oxygen species and is also associated with immune dysfunction. We examined the efficacy of resveratrol and vitamin E on the immunomodulatory activity and vascular function in mice with liver abnormalities induced by chronic ethanol consumption by measuring the protein, liver-specific transaminase enzymes, antioxidant enzymes and non-enzymes such as reduced glutathione (GSH) content, thiobarbituric acid reactive substance (TBARS) level, nitrite level, and activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) and glutathione peroxidase (GPx) and glutathione-S-transferase (GST), and cytokines such as interleukin (IL)-2, IL-4, IL-10, tumor necrosis factor (TNF)-alpha, gamma interferon (IFN-gamma), vascular endothelial growth factor (VEGF)-A and transforming growth factor (TGF)-beta1 in mice blood. Ethanol (1.6 g/kg body wt/day) exposure for 12 wks significantly increased TBARS and nitrite levels and GST activity, and significantly decreased GSH content and the activities of SOD, CAT, GR and GPx in whole blood hemolyzate of 8-10 wks-old male BALB/c mice (weighing 20-30 g). Ethanol exposure also elevated the activities of transaminase enzymes (AST and ALT), IL-10, TNF-alpha, IFN-gamma, VEGF-A and TGF-beta1, while decreasing the albumin concentration and IL-4 activity in the serum. Both resveratrol (5 mg kg(-1) day(-1)) and vitamin E (80 mg kg(-1) day(-1)) treatment significantly reduced AST, ALT, GST, IL-10, TNF-alpha, IFN-gamma, VEGF-A and TGF-beta1 activities and levels of TBARS and nitrite, and elevated albumin content, GSH level and activities of SOD, CAT, GR and GPx, compared to ethanol-treated group. Thus, results from the study demonstrated that both resveratrol (5 mg kg(-1) day(-1)) and vitamin E (80 mg kg(-1) day(-1)) can effectively ameliorate ethanol (1.6 g kg(-1) day(-1))-induced oxidative challenges, immunomodulatory activity and angiogenesis processes.     

The role of Acanthamoeba castellanii (T4 genotype) antioxidant enzymes in parasite survival under H2O2-induced oxidative stress

Acanthamoeba castellanii (A. castellanii) is an important opportunistic parasite. Induction of oxidative stress by the host immune system is one of the most important defense strategies against parasites. Hence, parasites partly deal with oxidative stress by different mechanisms. Identifying resistance mechanisms of A. castellanii parasites against oxidative stress is important to achieve a new therapeutic approach. Thus, this study aimed to understand the resistance mechanisms of A. castellanii, against oxidative stress. Trophozoites of A. castellanii were treated with different concentrations of H₂O₂. The half maximal inhibitory concentration (IC₅₀) of H₂O₂ was determined using the MTT assay. The induction of oxidative stress was confirmed by flow cytometer. The activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) were determined. The gene expression levels of CAT and SOD were measured by qRT-PCR. Furthermore, 3-amino-1:2:4-triazole (3-AT) and potassium cyanide (KCN) were used as specific inhibitors of CAT and SOD, respectively. Cell cycle assay and the apoptosis were evaluated by flow cytometer. The activities of SOD, CAT, GR, and GPx, showed an increase in oxidative stress. The cell cycle analysis revealed that most of the cellular population was in G0 and G1 phases. The apoptosis increased in oxidative stress conditions. Moreover, the apoptosis significantly increased after the specific inhibition of CAT and SOD under oxidative stress. The gene expression levels of CAT and SOD significantly increased under oxidative stress. A. castellanii can resist the host immune system through various mechanisms, including evoking its antioxidant enzymes. Therefore, by reducing or inhibiting the activity of the parasite's antioxidant enzymes such as SOD and CAT, it is possible to cope with A. castellanii.     

Protective effect of SnCl2 on K2Cr2O7-induced nephrotoxicity in rats: the indispensability of HO-1 preinduction and lack of association with some antioxidant enzymes

We have shown that the ameliorative effect of stannous chloride (SnCl2) pretreatment on potassium dichromate (K2Cr2O7)-induced renal damage 24 h after K2Cr2O7 injection was associated with the induction of heme oxygenase-1 (HO-1). In this work we evaluated: (a) if the protective effect of SnCl2 (given 12 h before K2Cr2O7) is associated with changes in the renal activity of HO-1, superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), and catalase (CAT) 24 and 48 h after K2Cr2O7 injection, and (b) if HO-1 induction is indispensable before K2Cr2O7 injection. It was found that the protective effect of SnCl2 on renal function was observed both at 24 and 48 h reaching its maximum at 24 h when HO-1 expression was higher. Cu,Zn-SOD, Mn-SOD, and GR activities remained unchanged whereas GPx and CAT activities decreased at 48 h in K2Cr2O7-treated rats. The activity of Cu,Zn-SOD, Mn-SOD, GPx, CAT, and GR was unchanged in the SnCl2-treated rats. To fulfill the objective (b) groups of rats treated with K2Cr2O7 and SnCl2 (given at the same time or 12 h after K2Cr2O7) were studied 24 h after K2Cr2O7-injection. The simultaneous injections of SnCl2 and K2Cr2O7 had no protective effect whereas the injection of SnCl2 12 h after K2Cr2O7 exacerbated renal damage. In conclusion, the protective effect of SnCl2 on K2Cr2O7-induced nephrotoxicity is associated with HO-1 induction and not with other antioxidant enzymes (Cu,Zn-SOD, Mn-SOD, GPx, GR, and CAT) and SnCl2 has a preventive and not a therapeutic effect on renal damage induced by K2Cr2O7.