GSH Glutathione Peroxidase Activity Research Articles

Selenium Protects ARPE-19 and ACBRI 181 Cells against High Glucose-Induced Oxidative Stress.

Diabetic retinopathy (DR), a complication of diabetes mellitus (DM), can cause severe visual loss. The retinal pigment epithelium (RPE) plays a crucial role in retinal physiology but is vulnerable to oxidative damage. We investigated the protective effects of selenium (Se) on retinal pigment epithelium (ARPE-19) and primary human retinal microvascular endothelial (ACBRI 181) cells against high glucose (HG)-induced oxidative stress and apoptotic cascade. To achieve this objective, we utilized varying concentrations of D-glucose (ranging from 5 to 80 mM) to induce the HG model. HG-induced oxidative stress in ARPE-19 and ACBRI 181 cells and the apoptotic cascade were evaluated by determining Ca2+ overload, mitochondrial membrane depolarization, caspase-3/-9 activation, intracellular reactive oxygen species (ROS), lipid peroxidation (LP), glutathione (GSH), glutathione peroxidase (GSH-Px), vascular endothelial growth factor (VEGF) and apoptosis levels. A cell viability assay utilizing MTT was conducted to ascertain the optimal concentration of Se to be employed. The quantification of MTT, ROS, VEGF levels, and caspase-3 and -9 activation was accomplished using a plate reader. To quantitatively assess LP and GSH levels, GSH-Px activities were utilized by spectrophotometer and apoptosis, mitochondrial membrane depolarization, and the release of Ca2+ from intracellular stores were evaluated by spectrofluorometer. Our investigation revealed a significant augmentation in oxidative stress induced by HG, leading to cellular damage through modulation of mitochondrial membrane potential, ROS levels, and intracellular Ca2+ release. Incubation with Se resulted in a notable reduction in ROS production induced by HG, as well as a reduction in apoptosis and the activation of caspase-3 and -9. Additionally, Se incubation led to decreased levels of VEGF and LP while concurrently increasing levels of GSH and GSH-Px. The findings from this study strongly suggest that Se exerts a protective effect on ARPE-19 and ACBRI 181 cells against HG-induced oxidative stress and apoptosis. This protective mechanism is partially mediated through the intracellular Ca2+ signaling pathway.

Effect of Selenium on Brain Injury in Chickens with Subacute Arsenic Poisoning.

The aim of this study was to investigate the effects of different doses of selenium (Se) on oxidative damage and neurotransmitter-related parameters in arsenic (As)-induced broiler brain tissue damage. Two hundred 1-day-old avian broilers were randomly divided into five groups and fed the following diets: control group (As 0.1 mg/kg + Se 0.2 mg/kg), As group (As 3 mg/kg + Se 0.2 mg/kg), low-Se group (As 3 mg/kg + Se 5 mg/kg), medium-Se group (As 3 mg/kg + Se 10 mg/kg), and high-Se group (As 3 mg/kg + Se 15 mg/kg). Glutathione (GSH), glutathione peroxidase (GSH-PX), nitric oxide (NO), nitric oxide synthase (NOS) activity, glutamate (Glu) concentration, glutamine synthetase (GS) activity, acetylcholinesterase (TchE) activity, and the apoptosis rate of brain cells were measured. The results showed that 3 mg/kg dietary As could induce oxidative damage and neurotransmitter disorder of brain tissue, increase the apoptosis rate of brain cells and cause damage to brain tissue, decrease activities of GSH and GSH-PX, decrease the contents of NO, decrease the activities of iNOS and tNOS, increase contents of Glu, and decrease activities of Gs and TchE. Compared with the As group, the Se addition of the low-Se and medium-Se groups protected against As-induced oxidative damage, neurotransmitter disorders, and the apoptosis rate of brain cells, with the addition of 10 mg/kg Se having the best effect. However, 15 mg/kg Se not only did not produce a protective effect against As damage but actually caused similar or severe damage.

SMER28 Attenuates Dopaminergic Toxicity Mediated by 6-Hydroxydopamine in the Rats via Modulating Oxidative Burdens and Autophagy-Related Parameters

Parkinson's disease is the second most common neurodegenerative disease that occurs due to cellular autophagy deficiency and the accumulation of alpha-synuclein in the dopaminergic neurons of the substantia nigra pars compacta (SNc) of the brainstem. The SMER28 (also known as 6-Bromo-N-prop-2-enylquinazolin-4-amine) is an autophagy inducer. In this study, the neuroprotective effects of SMER28 were evaluated on autophagy induction, antioxidant system activation, and microgliosis attenuation. The Parkinson's disease model was developed in the male Wistar rats by injection of 6-OHDA into the left striatum. Apomorphine-induced behavior assessment test and SNc cell counting were performed to investigate the neuroprotective effects of SMER28. This study examined the pharmacological roles of SMER28, especially by focusing on the autophagy (p62/ SQSTM1 and LC3II/LC3I ratio where LC3 is microtubule-associated protein 1A/1B-light chain 3), inhibiting free radicals, and activating the antioxidant system. The levels of malondialdehyde (MDA), reactive oxygen species (ROS), glutathione (GSH), GSH/glutathione peroxidase (GPX), superoxide dismutase (SOD) activity and nuclear factor-erythroid 2-related factor-2 (Nrf2) were measured to evaluate the antioxidant activity of SMER28. Moreover, Iba-1 (ionized calcium binding adaptor molecule, indicating microgliosis) and tyrosine hydroxylase immunoreactivities were evaluated in the SNc. In the behavioral assessment, SMER28 (50µg/kg) attenuated damages to the SNc dopaminergic neurons, characterized by improved motor function. The tissue observations revealed that SMER28 prevented the destruction of SNc neurons and attenuated microgliosis as well. It also reduced MDA and ROS production and increased GSH, GPX, SOD, and Nrf2 activities by inducing autophagy (decreasing p62 and increasing LC3II/LC3I ratio). Consequently, possibly with further studies, it can be considered as a drug for neurodegenerative diseases with proteinopathy etiology.

CHARD (BETA VULGARIS VAR. CICLA) EXTRACT MODULATES ZINC STATUS, GLUCOSE LEVEL AND ANTIOXYDANT VALUES IN DIABETIC RATS FED ZINC DEFICIENCY DIET

Objective: Oxidative stress which comes from hyperglycemia, it accelerates the development of cellular and vascular damage complications in diabetes, but the antioxidants may play a beneficial role in its prevention. Several plants extracts have an antioxidant activity and the ability to reduce oxidative stress in diabetes. Thus this study was conducted to investigate the effect of Beta vulgaris var cicla extract on zinc status, glucose concentration and antioxidant parameters in streptozotocin-diabetic rats fed zinc deficiency diet.Methods: Twenty-eight male albino (Wistar) rats were divided into four groups: two groups fed a zinc-sufficient diet one non-diabetic and the other diabetic, while the others two diabetic groups were fed a zinc-deficient diet, one non-treated group and the other treated with the extract of Beta vulgaris var cicla. After 21 d of dietary manipulation, fasting animals were scarified. Blood glucose, tissues zinc (femur, liver, kidney), malondialdehyde (MDA), reduced glutathione (GSH), glutathione peroxidase (GSH-Px) and glutathione-S-transferase (GST) were evaluated.Results: Body weight gain of zinc-deficient diabetic animals was lower than that of zinc-adequate diabetic animals. It was noticed also that inadequate dietary zinc intake increased glucose and MDA levels. In addition, zinc deficiency diet led to a decrease in zinc tissues, GSH concentration both GST and GSH-Px activities. However, Oral administration of Beta vulgaris extract significantly decreased both serum glucose and MDA (p<0.001) levels, with a significant increase in body weight gain (p<0.001), GSH concentration (p<0.05, P<0.001), GST (p<0.05, p<0.001) and GSH-Px (p<0.001) activities.Conclusion: The present study showed that Beta vulgaris var cicla supplementation presumably acting as an antioxidant, and it can be a natural source for the reduction of diabetes development caused by zinc deficiency.

Paeoniflorin attenuates hepatic ischemia/reperfusion injury via anti-oxidative, anti-inflammatory and anti-apoptotic pathways.

During liver surgery, hepatic blood flow needs to be blocked in order to reduce bleeding, which inevitably results in hepatic ischemia/reperfusion injury (HI/R). Paeoniflorin (PF) is the main active ingredient of the traditional Chinese herbal medicine peony, which has been shown to exert anti-oxidative and anti-apoptotic properties. In the present study, a mouse model of HI/R was generated by clamping the hepatoportal vein, hepatic artery, and hepatic duct of BALB/c mice with a vascular clamp for 30 min, followed by reperfusion for 6 h under anesthesia. Six mice in the three PF treatment groups (5, 10 and 20 mg/kg) were then injected with PF, via the tail vein. A sham group, consisting of six mice that did not undergo the procedure, and a vehicle group, consisting of 6 mice that underwent the procedure but subsequently received injections of physiological saline only, were used as controls. Liver injury was indicated by serum levels of the enzymes alanine transaminase (ALT) and aspartate transaminase (AST). The activities of oxidative stress biomarkers, including superoxide dismutase (SOD), glutathione (GSH), glutathione peroxidase (GSH-PX) and malondialdehyde (MDA), were also measured. Furthermore, the activity of caspase-3 was analyzed in hepatic tissue using a commercial kit. Treatment with PF significantly attenuated HI/R injury histologically, as compared with the vehicle group. In addition, significant reductions in the serum levels of ALT and AST were observed in the PF-treated ischemic mice. Furthermore, treatment with PF enhanced the activities of hepatic tissue SOD, GSH and GSH-PX, but decreased the MDA content. Treatment of ischemic mice with PF markedly reduced the expression levels of inflammatory mediators, including nuclear factor-κB, tumor necrosis factor-α, interleukin (IL)-6, and IL-1β, and decreased the HI/R injury-induced expression of caspase-3. The results of the present study suggest that PF attenuates the HI/R injury of mice via anti-oxidative, anti-inflammatory and anti-apoptotic activities.

Investigation of the protective effect of ellagic acid for preventing kidney injury in rats exposed to nicotine during the fetal period

We investigated the possible protective effects of ellagic acid on rat kidneys exposed to nicotine during the fetal period. Twenty pregnant female rats were divided randomly into four groups: control (C), nicotine (N), ellagic acid (EA) and nicotine + ellagic acid (N + EA). Nicotine and ellagic acid treatments were continued throughout the pregnancies and for 15 days after delivery. On day 15, all neonatal pups were sacrificed and their kidneys were removed for biochemical and histopathological examination. The nicotine treatment significantly decreased body weight, total glutathione (GSH), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities, and increased malondialdehyde (MDA) and nitric oxide (NO) levels in the N group compared to controls. EA treatment ameliorated decreased body weight, GSH, GSH-Px and SOD activities, and increased MDA and NO levels in group N + EA compared to group N (p < 0.05). Nicotine caused kidney damage as shown by incomplete development of glomeruli and Bowman's capsules. Nicotine also caused greater apoptosis in group N compared to group C. Ellagic acid treatment produced histological kidney structure that was closer to normal and it exerted an anti-apoptotic effect in the N + EA group compared to the N group. EA played a protective role against nicotine-induced nephrotoxicity and oxidative stress in rats owing to its antioxidant, radical scavenging and anti-apoptotic effects.

Activation of the Nrf2 defense pathway contributes to neuroprotective effects of phloretin on oxidative stress injury after cerebral ischemia/reperfusion in rats

Oxidative stress is considered a major contributing factor in cerebral ischemia/reperfusion injury. Phloretin, a dihydrochalcone belonging to the flavonoid family, is particularly rich in apples and apple-derived products. A large body of evidence demonstrates that phloretin exhibits anti-oxidant properties, and phloretin has potential implications for treating oxidative stress injuries in cerebral ischemia/reperfusion. Therefore, the neuroprotective and antioxidant effects of phloretin against ischemia/reperfusion injury, as well as related probable mechanisms, were investigated. The cerebral ischemic/reperfusion injury model was reproduced in male Sprague–Dawley rats through middle cerebral artery occlusion. At 24h after reperfusion, neurological score, infarct volume, and brain water content were assessed. Oxidative stress was evaluated by superoxide dismutases (SOD), glutathione (GSH), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) levels. Nrf2 expression was measured by RT-PCR and western blot. Consequently, results showed that phloretin pretreatment for 14days significantly reduced infarct volume and brain edema, and ameliorated neurological scores in focal cerebral ischemia/reperfusion rats. SOD, GSH and GSH-Px activities were greatly decreased, and MDA levels significantly increased after ischemia/reperfusion injury. However, phloretin pretreatment dramatically suppressed these oxidative stress processes. Furthermore, phloretin upregulated Nrf2 mRNA and protein expression of in ischemia/reperfusion brain tissue. Taken together, phloretin exhibited neuroprotective effects in cerebral ischemia/reperfusion, and the mechanisms are associated with oxidative stress inhibition and Nrf2 defense pathway activation.

Melatonin attenuates apoptosis and mitochondrial depolarization levels in hypoxic conditions of SH-SY5Y neuronal cells induced by cobalt chloride (CoCl2)

Melatonin (MEL) and its metabolites serve as endogenous reactive oxygen species (ROS) scavengers and have a wide spectrum of antioxidant activity. Cobalt chloride is one of the commonly used hypoxia-mimetic agents, due to blocking the degradation of and triggering the accumulation of hypoxia-inducible factor-1 alpha (HIF-1α ) protein, which is very well known as a critical regulator of the cellular response against hypoxia. In the current study we aimed to determine the possible protective effects of melatonin on a cobalt chloride-induced hypoxia model of SH-SY5Y neuronal cells. Group I was the control group and SH-SY5Y cells were incubated in normal culture media without any chemical administration. In Group II, SH-SY5Y cells were incubated with 1 μM MEL for 24 h. In Group III cells were incubated with 200 μM cobalt chloride for 24 h. The last group, Group 4, was a combination group of cobalt chloride and MEL. Cells were preincubated with 1 μM for 12 h and then 200 μM cobalt chloride for 24 h. We performed the cell viability test (MTT) and checked the caspase-3 and -9 activities and the lipid peroxidation (LP), reduced glutathione (GSH), glutathione peroxidase (GSH-Px), mitochondrial depolarization, and intracellular ROS levels. We observed that cobalt chloride increased intracellular ROS, caspase-3 and -9, lipid peroxidation, and mitochondrial membrane depolarization values, while decreasing GSH levels and GSH-Px activity. However, GSH and GSH-Px values were increased by melatonin treatment although lipid peroxidation level, intracellular ROS production, and caspase-3 and -9 activities were decreased by the treatment. In conclusion, we observed that melatonin incubation protects neuronal cells against hypoxia-induced oxidative stress.

Effects of 5-Fluorouracil on Oxidative Stress and Calcium Levels in the Blood of Patients with Newly Diagnosed Colorectal Cancer

The administration of chemotherapeutic agents for colorectal carcinoma is associated with an increase in oxidative stress and a concomitant decrease in antioxidant and element levels in the blood. This study investigated the effects of 5-fluorouracil (5-FU) chemotherapy on the levels of lipid peroxidation, reduced glutathione (GSH), glutathione peroxidase (GSH-Px), antioxidant vitamins, and elements in colorectal cancer patients. Twelve patients with newly diagnosed colorectal carcinoma and 12 healthy subjects were included in this study. Blood samples were collected from both the healthy controls and patients. 5-FU was intravenously administered to the patients for 6weeks, and blood samples were collected again from the treatment group. In the patient group, lipid peroxidation levels were increased in both the plasma and erythrocyte samples, whereas GSH-Px activity and concentrations of GSH, vitamin E, and β-carotene in erythrocytes were decreased. The oxidant, antioxidant, and plasma calcium values were lower in 5-FU-treated patients than in the controls. Plasma vitamin A, chloride, sodium, and potassium concentrations did not change with 5-FU treatment. In conclusion, oxidative stress in patients with newly diagnosed colorectal cancer is attributable to the disease and not to 5-FU treatment. Blood vitamin E, β-carotene, GSH, and GSH-Px levels could be useful as early biomarkers of the prognosis of colorectal cancer patients.

Effects of Selenium on Calcium Signaling and Apoptosis in Rat Dorsal Root Ganglion Neurons Induced by Oxidative Stress

Ca(2+) is well known for its role as crucial second messenger in modulating many cellular physiological functions, Ca(2+) overload is detrimental to cellular function and may present as an important cause of cellular oxidative stress generation and apoptosis. The aim of this study is to investigate the effects of selenium on lipid peroxidation, reduced glutathione (GSH), glutathione peroxidase (GSH-Px), cytosolic Ca(2+) release, cell viability (MTT) and apoptosis values in dorsal root ganglion (DRG) sensory neurons of rats. DRG cells were divided into four groups namely control, H(2)O(2) (as a model substance used as a paradigm for oxidative stress), selenium, selenium + H(2)O(2). Moderate doses and times of H(2)O(2) and selenium were determined by MTT test. Cells were preterated 200 nM selenium for 30 h before incubatation with 1 μM H(2)O(2) for 2 h. Lipid peroxidation levels were lower in the control, selenium, selenium + H(2)O(2) groups than in the H(2)O(2) group. GSH-Px activities were higher in the selenium groups than in the H(2)O(2) group. GSH levels were higher in the control, selenium, selenium + H(2)O(2) groups than in the H(2)O(2) group. Cytosolic Ca(2+) release was higher in the H(2)O(2) group than in the control, selenium, selenium + H(2)O(2) groups. Cytosolic Ca(2+) release was lower in the selenium + H(2)O(2) group than in the H(2)O(2). In conclusion, the present study demonstrates that selenium induced protective effects on oxidative stress, [Ca(2+)](c) release and apoptosis in DRG cells. Since selenium deficiency is a common feature of oxidative stress-induced neurological diseases of sensory neurons, our findings are relevant to the etiology of pathology in oxidative stress-induced neurological diseases of the DRG neurons.

Effect of gypenosides on DMN-induced liver fibrosis in rats

To study the effect of gypenosides on DMN-induced liver fibrosis in rats. A rat liver fibrosis model was established by injecting DMN intraperitoneally. Four weeks later, model rats were randomly devided into three groups: the model group, the gypenosides treated group (200 mg x kg(-1)) and the colchicine treated group (0.1 mg x kg(-1)), with 10 specimens for each group. After a 2-week treatment, following parameters were observed: (1) last body weight, weight ratio between liver and spleen; (2) content of liver hydroxyproline (Hyp); (3) activity of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyltransferase (gamma-GT), content of albumin (Alb) and total bilirubin( TBiL) in serum; (4) liver pathology (Sirius red staining and HE staining); (5) activity of liver superoxide dismutase (SOD), glutathione reduced (GSH), glutathione peroxidase (GSH-Px) and content of liver maleic dialdehyde (MDA). There were classic liver cirrhosis pathological changes in model groups. Compared with the normal group, liver Hyp content, activity of serum ATL, AST, gamma-GT and content of serum TBiL, MDA of model groups significantly increased; content of serum Alb and liver GSH, activity of liver SOD and GSH-Px decreased significantly in model groups. In comparison with the model group, liver cirrhosis remarkable improved in the gypenosides group, content of liver Hyp reduced significantly (P < 0.01), which was equal to the colchicine group. Compared with the model group, liver function parameters improved markedly in the gypenosides group; liver SOD and GSH-Px activities significantly increased; MDA content reduced significantly (P < 0.05). Gypenosides shows an effect in treating DMN-induced liver fibrosis in rats.

Effects of Lycopene and Proanthocyanidins on Hepatotoxicity Induced by Mercuric Chloride in Rats

To evaluate the protective potential of lycopene (Lyc) and proanthocyanidins (PCs) against mercuric chloride (HgCl(2))-induced hepatotoxicity, the study focused on the mechanism of oxidative stress. Firstly, the rats were subcutaneously (s.c.) injected with 0, 2.2, 4.4, and 8.8 μmol/kg HgCl(2). Additionally, 40 mg/kg Lyc and 450 mg/kg PCs were given to the rats intragastrically (i.g.) before exposure to 8.8 μmol/kg HgCl(2). Then, body weight, liver weight coefficient, mercury (Hg) contents, histological feature, ultrastructure, apoptosis, reactive oxygen species (ROS), glutathione (GSH), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and malondialdehyde (MDA) in the liver were measured. Lactate dehydrogenase (LDH) and alanine transaminase (ALT) in serum were determined. After exposure to different concentrations of HgCl(2), it was found that Hg contents, pathological and ultrastructure injury, activities of LDH and ALT, apoptosis, and levels of ROS, GSH, and MDA increased and the activities of SOD and GSH-Px decreased in a concentration-dependent manner. Further investigation found that pretreatment with Lyc and PCs inhibited ROS production, protected antioxidant enzymes, and reversed hepatotoxicity. We concluded that Lyc and PCs had hepatoprotective effects on HgCl(2)-induced toxicity by antagonizing oxidative stress in rat liver.

Protective effects of garlic oil on n-hexane-induced neurotoxicity in rats via inhibition of hepatic alcohol dehydrogenase activity

To study the protective effects of garlic oil (GO) on the peripheral nerve injuries induced by n-hexane. Male Wistar rats were randomly divided into four groups (10 rats in each group): the control, the n-hexane treatment (2000 mg/kg), the low dose GO, and the high dose GO groups. The rats in the low and high doses of GO groups were pretreated with GO (40 and 80 mg/kg) before exposure to n-hexane (2000 mg/ kg), while the animals of the n-hexane treatment group were given normal saline and then 2000 mg/ kg n-hexane. The rats were exposed to GO and n-hexane 6 times a week for 10 weeks. The gait scores and staying time on the rotating rod for all rats were detected every two weeks. The rats were sacrificed at the end of ten weeks, then the levels of alcohol dehydrogenase (ADH), maleic dialdehyde (MDA), reduced glutathione (GSH), glutathione peroxidase(GSH-Px), total antioxidation capacity(T-AOC) and the ability of inhibition of *OH in livers were examined. The gait scores increased significantly and the time staying on the rotating rod obviously decreased in rats of n-hexane treatment group, as compared with control group (P < 0.05 or P < 0.01). In the hepatic tissues of n-hexane group, the levels of MDA and ADH significantly increased, the activities of GSH-Px, T-AOC and the ability of inhibition of *OH obviously decreased, as compared to control group (P < 0.05 or P < 0.01). In 2 GO groups, the gait scores and the staying time on the rotating rod were significantly improved, the levels of MDA and ADH significantly decreased, the activities of GSH-Px, T-AOC and the ability of inhibition of *OH obviously increased, as compared with n-hexane group (P < 0.05 or P < 0.01 ). ADH could play an important role in the protective effects induced by garlic oil on the peripheral nerve injuries produced by n-hexane.

Effects of polysaccharides of the Euphoria Longan (Lour.) Steud on focal cerebral ischemia/reperfusion injury and its underlying mechanism

Objective: To investigate the effects of polysaccharides of the Euphoria Longan (Lour.) Steud on focal cerebral ischemia/reperfusion(I/R) injury in rats.Methods: In this study, spectrophotometry was employed to observe the effects of polysaccharides of the Euphoria Longan (Lour.) Steud on and ·OH in vitro. The operation was performed to induce the middle cerebral artery occlusion (MCAO) in rats. The influences of polysaccharides on the neurological function score, the brain water content, the infarct volume, activities of superoxide dismutase (SOD), glutathione (GSH), glutathione peroxidase (GSH-Px) and myeloperoxidase (MPO), the contents of malondialdehyde (MDA), the protein levels of Bcl-2 and Bax, the concentration of tumour necrosis factor-α (TNF-α) and interleukin-1β (IL-β) in brain tissue were measured.Results: Compared with the I/R group, polysaccharides of the Euphoria Longan (Lour.) Steud could obviously reduce the neurological score, the infract volume, the brain water content, MDA content, MPO activity, TNF-α and IL-1β level, expression of Bax, and increase SOD, GSH, GSH-Px activity and expression of Bcl-2.Conclusion: The data suggest that polysaccharides of the Euphoria Longan (Lour.) Steud are capable of alleviating I/R injury by a mechanism that may involve decreasing oxidative stress.

Protective effects of clarithromycin in rats with hypoxia/reoxygenation-induced intestinal injury

Background This study was designed to determine the role of oxidative stress, nitric oxide (NO), and glutathione-related antioxidant enzymes in rat pups with hypoxia/reoxygenation (H/R)-induced bowel injury and to evaluate the potential benefits of prophylactic clarithromycin. Methods One-day-old Wistar albino rat pups (N = 21) were randomly divided into 3 groups: group I (control), group II (exposed to H/R), and group III (clarithromycin + H/R). Clarithromycin was administered (40 mg/kg) subcutaneously to group III for 3 days. On the fourth day, all rats except controls were exposed to H/R and were killed at 6 hours after H/R. Histopathologic injury scores (HIS), malonyldialdehyde, glutathione (GSH), glutathione-peroxidase (GSH-Px) activities, and NO levels were measured on intestinal samples. Results Whereas there was no difference for malonyldialdehyde levels among groups, HIS and NO levels were higher in group II than groups I and III ( P < .05). However, GSH and GSH-Px activities were lower in group II than groups I and III ( P < .05). Clarithromycin significantly increased GSH and GSH-Px activities and reduced HIS and NO levels in group III. Conclusion This study showed that oxidative stress and NO contributed to the pathogenesis of H/R-induced bowel injury and that clarithromycin had a protective effect on bowel injury owing to anti-inflammatory and antioxidant effects.

The influence of cysteine and taurine on microscopic–oxidative stress parameters and fertilizing ability of bull semen following cryopreservation

Oxidative stress significantly damages sperm functions such as motility, functional integrity, endogenous antioxidant enzyme activities and fertility due to lipid peroxidation induced by reactive oxygen species (ROS). The aim of this study was to determine the effects of antioxidants such as taurine and cysteine in Bioxcell ® extender on standard semen parameters, fertilizing ability, lipid peroxidation (LPO) and antioxidant activities comprising reduced glutathione (GSH), glutathione peroxidase (GSH-Px), catalase (CAT) and superoxide dismutase (SOD) after the cryopreservation/thawing of bull semen. Nine ejaculates for each bull were included in the study. Three groups, namely taurine (2 mM), cysteine (2 mM), and control, were designed to analyze the antioxidants in Bioxcell ®. Insemination doses were processed so that each 0.25-ml straw contained 15 × 10 6 sperm. The addition of cysteine led to higher motility, compared to the other groups ( P < 0.001). Cysteine showed a greater protective effect on the percentages of acrosome damage and total abnormalities in comparison to the other groups ( P < 0.001). No significant differences were observed in hypo-osmotic swelling test (HOST), following supplementation with antioxidants during the freeze–thawing process. No significant difference was observed in non-return rates among groups. In biochemical assays, the additives did not show effectiveness on the elimination of malondialdehyde (MDA) formation and maintenance of GSH and GSH-Px activities, when compared to controls. CAT activity (35.1 ± 8.1 kU/g) was demonstrated to be significantly higher upon the addition of 2 mM taurine ( P < 0.001), while the level of MDA increased, indicating oxidative stress in this group. SOD activity (21.4 ± 2.9 U/g protein) was significantly elevated in the group with cysteine, compared to the other groups ( P < 0.001).

Effects of anti-oxidant additives on microscopic and oxidative parameters of Angora goat semen following the freeze–thawing process

The anti-oxidant system of reduced glutathione (GSH), glutathione peroxidase (GSH-PX), catalase (CAT), and superoxide dismutase (SOD) has been described as a defense functioning mechanism against lipid peroxidation (LPO) in semen, and is important in maintaining sperm motility and viability. This anti-oxidant capacity of sperm cells may be insufficient in preventing LPO during the freeze–thawing process. The aim of this study was thus to determine the influence of varying doses of anti-oxidant additives on standard semen parameters, lipid peroxidation and anti-oxidant activities after the freeze–thawing of goat semen. Ejaculate samples (artificial vagina) obtained from 4 mature Angora goats were evaluated and pooled at 37 °C. The semen samples diluted with a Tris-based extender, containing taurine (25, 50, 75 mM), trehalose (25, 50, 75 mM), and cysteine (5, 10, 15 mM), and an extender containing no anti-oxidant additives (control) were again evaluated. Diluted semen was cooled down to 5 °C and frozen in 0.25 ml French straws, prior to being stored in liquid nitrogen. Frozen straws were thawed in a water bath (37 °C) for 30 s for microscopic sperm evaluation. Upon evaluation of parameters for semen quality, the use of a Tris-based extender supplemented with anti-oxidant additives was found to cause no significant improvement in sperm mortality, when compared to the controls. Increasing doses of taurine and trehalose decreased ( P < 0.05) the sperm motility following the freeze–thawing of the goat semen. In biochemical assays, the application of taurine (75 mM) produced the lowest level of malondialdehyde (MDA) (4.46 ± 0.31 nmol/ml), compared to the controls ( P < 0.001). Lower GSH levels were higher in the groups in which cysteine was included at 10 and 15 mM (3.27 ± 0.11 and 3.45 ± 0.28 nmol/ml) – compared to the group which received 5 mM cysteine, as well as the controls (2.27 ± 0.08 and 2.50 ± 0.08 nmol/ml respectively, P < 0.001). Compared to the controls, taurine at a concentration of 25 and 75 mM, and increasing doses (50 and 75 mM) of trehalose, significantly increased the GSH-PX activity ( P < 0.01). The maintenance of CAT activity was demonstrated to be higher with the addition of 10 and 15 mM cysteine, compared to the other groups ( P < 0.001). Vitamin A (VitA) levels were significantly higher, compared to the controls (267.34 ± 9.68 mg/dl and 267.34 ± 9.68 mg/dl, respectively), when 25 mM taurine (329.61 ± 6.35 mg/dl) and 10 mM (318.64 ± 6.34 mg/dl) cysteine was added to the extender ( P < 0.001). The results of this study provide a new approach to the cryopreservation of Angora goat semen and could contribute to the improvement of this technology in the goat industry.

Shengmai San reduces hepatic lipids and lipid peroxidation in rats fed on a high-cholesterol diet

Shengmai San (SMS), which is comprised of the medicinal herbs of Panax ginseng C.A. Meyer, Schisandra chinensis Baill., and Ophiopogon japonicus Ker-Gawl (2:1:2)., is a traditional Chinese medicine being used for treating coronary heart disease. The aim of this study was to investigate the effects of SMS on the plasma and liver lipids, lipid peroxidation and antioxidant systems in liver and heart of cholesterol-fed rats. Rats were fed on a high-cholesterol (0.5%) diet (control group), high-cholesterol diet containing 2% SMS (2% SMS group) and 4% SMS (4% SMS group) for four weeks. The oxidative stress marker (thiobarbituric acid reactive substances, TBARS) and antioxidant defense systems including glutathione (GSH), glutathione peroxidase (GSH-Px), glutathione-S-transferase (GST) and superoxide dismutase (SOD) activities in rat liver and heart were evaluated. Results showed that rats fed with SMS-containing diet had reduced the H 2O 2-induced erythrocytes susceptibility to hemolysis, and 4% SMS feeding rats had higher plasma GSH concentration compared to the animals fed with the control diet. However, SMS had no effect on plasma lipids (total cholesterol, triglyceride and high-density lipoprotein cholesterol) and TBARS concentration. On the other hand, rats fed with the 4% SMS diet reduced the hepatic cholesterol and triglyceride contents. Fecal bile acid excretion was significantly increased in rats fed with the SMS-containing diet. Higher hepatic GSH and lower TBARS concentrations were observed in rats fed with the 4% SMS diet compared with the rats fed with the control diet. No significant difference in activities of GSH-Px, GST and SOD was found in liver and heart after the SMS treatment. Results from this study indicate that the SMS may reduce hepatic lipids and lipid peroxidation in rats.

Lycopene, a Carotenoid, Attenuates Cyclosporine‐Induced Renal Dysfunction and Oxidative Stress in Rats

The aim of this study was to investigate the possible protective role of antioxidant treatment with lycopene on cyclosporine A-induced nephrotoxicity using biochemical and histopatological approaches. Adult male Sprague-Dawley rats were randomly divided into four groups. The control group received physiological saline; animals in the lycopene group received only lycopene (10 mg/kg); animals in the cyclosporine A group received only cyclosporine A (15 mg/kg) and animals in cyclosporine plus lycopene group received cyclosporine and lycopene for 21 days. The effects of lycopene on cyclosporine A-induced nephrotoxicity were evaluated by plasma creatinine, urea, sodium and calcium concentrations; kidney tissue thiobarbituric acid reactive species, reduced glutathione (GSH), glutathione peroxidase (GSH-Px) and catalase activities and histopatological examinations. Administration of cyclosporine A to rats induced a marked renal failure, characterized with a significant increase in plasma creatinine and urea concentrations. Cyclosporine A also induced oxidative stress as indicated by increased kidney tissue concentrations of thiobarbituric acid reactive species and GSH, and reduced activities of GSH-Px and catalase. Moreover, the kidneys of cyclosporine A-treated rats showed tubular necrosis, degeneration, dilatation, thickened basement membranes, luminal cast formation and inter-tubular fibrosis. Lycopene markedly reduced elevated plasma creatinine, urea levels and counteracted the deleterious effects of cyclosporine A on oxidative stress markers. In addition, lycopene ameliorated cyclosporine A-induced pathological changes including tubular necrosis, degeneration, thickened basement membranes and inter-tubular fibrosis when compared to the alone cyclosporine A group. These data indicate that the natural antioxidant lycopene might have protective effect against cyclosporine-induced nephrotoxicity and oxidative stress in rat.

Beneficial effects of caffeic acid phenethyl ester (CAPE) on the ischaemia-reperfusion injury in rat skin flaps

Reperfusion injury is a phenomenon that occurs when tissues are subjected to ischaemia for a variable period of time, after which they are reperfused. Many factors have been implicated in the cause of reperfusion injury including free radicals and neutrophils. Caffeic acid (3,4-dihydroxycinnamic acid) phenethyl ester (CAPE) is an active component of propolis from honeybee; it has anti-inflammatory and immunomodulatory properties, and protective effects against ischaemia-reperfusion (I/R) injury. We investigated the effects of CAPE on the survival of skin flaps in the rat. Eighteen Wistar rats were used, and randomly divided into three groups (n=6 rats each group): the control group (Group 1), ethanol group (Group 2), and CAPE group (Group 3). A caudally based rectangular flap, 3x10 cm in size, was elevated on the back of the rat, according to the method described by Khouri and colleagues. The flap was sutured back into its original place. In the control group, saline 0.2 ml/day was given intraperitoneally (i.p.). Five percent ethanol 0.2 ml/day was administered i.p. in the ethanol group, and CAPE 50 micromol/kg/day i.p. in the CAPE group. To observe the effects of CAPE, levels of malondialdehyde (MDA), nitric oxide (NO), glutathione (GSH), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) were measured from extracted skin tissue. Flap viability was evaluated seven days after the initial operation, measuring necrotic areas of flaps and total flap areas. MDA and NO levels were significantly decreased in CAPE group; and however, GSH, GSH-Px, and SOD enzyme activities were significantly increased in CAPE group. We believed that the CAPE had beneficial effects to improve the survival of skin flaps since it has antioxidative and anti-inflammatory properties, and protective effects against I/R injury.