Hexagonal boron nitride nanoparticles trigger oxidative stress by modulating thiol/disulfide homeostasis.

BACKGROUND: Hexagonal boron nitride nanoparticles (hBN NPs) are encouraging nanomaterials with unique chemical properties in medicine and biomedical fields. Until now, the optimal hBN NP's dosage and biochemical mechanism that can be used for in vivo systems has not been fully revealed. The main aim of this article is to reveal characteristics, serum and tissue interactions and any acute cytotoxic effect of different dose of hBN NPs for the first time. METHODS: hBN NPs at concentrations varying between 50-3200 µg/kg was administered by intravenous injection to Wistar albino rats (n = 80) divided into seven dosage and control groups. Blood and tissue samples were taken after 24 hours. RESULTS: Our findings suggested that higher doses hBN NPs caused oxidative stress on the serum of rats dose-dependently. However, hBN NPs did not affect thiol/disulfide homeostasis on kidney, liver, spleen, pancreas and heart tissue of rats. Furthermore, hBN NPs increased serum disulfide formation by disrupting the thiol/disulfide balance in rats. Also, LOOH and MPO levels increased at high doses, while CAT levels decreased statistically. CONCLUSION: The results revealed that hBN NPs induce oxidative stress in a dose-dependent manner by modulating thiol/disulfide homeostasis in rats at higher concentrations.

Protective effect of betaine against skeleton muscle apoptosis in rats induced by chronic alcohol and statin consumption.

AIM: The aim of the present study was to investigate the effect of apoptosis on rat skeletal muscle caused by chronic alcohol and statin consumption with modified liquid diet and to elucidate protective effects of betaine supplementation. METHODS: TNF-α (tumor necrosis factor), NF-kB (Nuclear Factor kappa B), cytochrome c and caspase-3 levels with or without betaine treatment in alcohol and/or statin-induced skeleton muscle apoptosis rats as well as in controls were measured in serum and tissue. Histologic examinations of the muscle tissues were also performed. RESULTS: In our study, betaine treated treatment groups we found that calpain and caspase activities and cytokine c release were decreased caused by alcohol, statin and more importantly alcohol+statin group and TNF and NF-kB levels were also close to the levels of control group. Similarly, significant improvements have been observed in our morphological and histological examination results also supporting our biochemical data. CONCLUSION: We found that combined consumption of ethanol and statin is capable of triggering apoptotic cell death in rat muscles more than the consumption of only alcohol or only statin. Betaine was able to reduced this muscle cell death induced by alcohol and/or statin consumption (Tab. 4, Fig. 4, Ref. 43).

The effects of L-NAME on DU145 human prostate cancer cell line: A cytotoxicity-based study.

Of all cancer types, prostate cancer is the second most common one with an age-standardized incidence rate of 29.3 per 100,000 men worldwide. Nitric oxide (NO) is both a radical and versatile messenger molecule involved in many physiological activities. NO was documented to be highly secreted and utilized by cancer cells. Nω-nitro-L-arginine methyl ester (L-NAME) is utilized for inhibiting NO synthase. Its worst long-term side effect is reported to be hypertension, hence less cytotoxic than chemotherapeutic agents. Herein, we carried out a cytotoxicity study on how different doses of L-NAME affect DU145 human prostate cancer cells. First, toxic doses of L-NAME were determined. Then, while antioxidant capacity was determined by glutathione and total antioxidant status, oxidative stress was evaluated by quantifying malondialdehyde, NO, and total oxidant status levels. Inflammatory effects of L-NAME were investigated by measuring tumor necrosis factor-α and interleukin-6 (IL-6) levels. Apoptotic effects of L-NAME were evaluated by measuring cytochrome C somatic and caspase 3 levels and by staining Bax protein. Finally, morphological analysis was performed. IC50 of L-NAME against DU145 cells was 12.2 mM. In L-NAME-treated DU145 cells, a dose-dependent increase in oxidative stress, inflammatory, and apoptotic marker proteins and decrease in antioxidant capacity were observed. While at the moderate dose of L-NAME, apoptotic changes were commonly observed, at higher doses, vacuolated and swollen cells were also recorded. We believe that the present study will encourage future studies by providing insights about dose and effects of L-NAME.

The examination of protective effects of gallic acid against damage of oxidative stress during induced-experimental renal ischemia-reperfusion in experiment.

AIM: In this study, probable effects of gallic acid were investigated in experimentally induced renal I/R injury in rats. MATERIAL AND METHODS: For this purpose, each group consisted of 7 Spraque dawley male albino rats. Groups were defined as follows; Group I: control group; Group II: I/R group; Group III, IV and V: I/R+Gallic acid (50, 100 and 200 mg.kg-1 respectively-i.p.). Left kidney was removed by nephrectomy except for Group I. I/R was induced in the other kidney. Gallic acid was given 15 mins before ischemia induction. SOD, CAT and Gpx activities were determined by electrophoresis. MDA, MPO levels were determined spectrophotometrically. Histopathological investigations were also performed in kidney tissues. BUN and Creatinine levels in serum were determined. RESULTS: BUN, Creatinine and MDA levels were statistically significant but MPO level was not statistically significantly increased in Group II. For SOD, CAT, Gpx activities in Group II, an increase was determined with respect to Group I. Histopathological investigations revealed widespread hyperemia in glomerulus, expansion of the structure between tubules and cell disruptions in Group II. In Group V (200 mg.kg-1 gallic acid), in terms of biochemical parameters, in spite of the significant decrease in BUN, Creatinine and MDA levels; a decrease was determined in SOD, CAT and Gpx isoenzyme activities. Group V showed histologically that I/R injury had been prevented to a greater extent and appearances were close to the control. CONCLUSION: As a result, in terms of our study, evaluations regarding kidney functions and histopathology have shown that gallic acid has protective effects in renal I/R injury (Tab. 2, Fig. 5, Ref. 36).

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.

Preventive effect of betaine on ethanol-induced membrane lipid composition and membrane ATPases.

The aim of this study was to observe ethanol-induced membrane injury and to investigate the protective effect of betaine against chronic ethanol toxicity. Rats were divided into three groups: control group (n = 8), ethanol (8 g/kg per day) group (n = 8) and ethanol plus betaine (0.5% w/v) group (n = 8). Cholesterol concentrations (P < 0.05) and the cholesterol/phospholipid (C/PL) molar ratio (P < 0.01) were significantly increased in the erythrocyte membranes of ethanol-treated rats compared with those of the control group. Cholesterol (P < 0.05) and the C/PL ratio (P < 0.01) were decreased to control group levels after betaine administration. The activities of Ca(2+)-Mg2+ ATPase and Na(+)-K+ ATPase were lower than those of the control group (both P < 0.001), but the activities of these enzyme were increased in the betaine treatment group (P < 0.05). Our findings show that chronic ethanol consumption may affect membrane functions and betaine administration may be a useful agent for the treatment of chronic ethanol toxicity.

Antioxidant enzyme activities and malondialdehyde levels related to aging.

BACKGROUND: Free oxygen radicals have been proposed as important causative agents of aging. We have evaluated age-related changes in antioxidant enzyme activities and lipid peroxidation. METHODS: We measured erythrocyte superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and plasma malondialdehyde (MDA) levels. One hundred and seventy six healthy subjects were divided into five groups: Group 1 (n = 25; 0.2-1 year-old), Group 2 (n = 28; 2-11 years), Group 3 (n = 23: 12-24 years), Group 4 (n = 40; 25-40 years), Group 5 (n = 60: 41-69 years). RESULTS: SOD activities in Group 5 were significantly lower than in the other groups (P < 0.001). GPx and CAT activities and MDA levels in Group 5 were significantly higher than the other groups (P < 0.001, respectively). CAT activity in Group 4 was significantly higher than group 1 and group 2 (respectively, P < 0.001), and in group 3 was high compared to Group 2 (P < 0.001). There were negative correlations between SOD activities and age (P < 0.001). Conversely, there were positive correlations between CAT, GPx and MDA levels and age (P < 0.001). CAT activities of women in Group 2 were found to be high compared to the men (P < 0.05). MDA levels of women in Group 5 were higher than in the male groups (P < 0.001). CONCLUSIONS: We found age-related differences in erythrocyte antioxidant enzyme activities. Furthermore, peroxidative injury is raised in the aging process.

Antioxidant status and lipid peroxidation in hemodialysis patients undergoing erythropoietin and erythropoietin-vitamin E combined therapy.

In this study, plasma and red blood cell (RBC) antioxidant status and plasma lipid peroxidation were investigated in 46 hemodialysis patients. In addition, the effect of erythropoietin (EPO) and EPO-vitamin E combination therapy on plasma and RBC antioxidant status, and plasma lipid peroxidation were examined. There were 10 healthy subjects in the control group and 10 hemodialysis patients in the untreated group. The third group included 36 hemodialysis patients that were given EPO (100 U/kg) for 3 months, 3 times per week. The fourth group included 36 hemodialysis-patients from the EPO group that were given EPO at a 50% decreased dose + vitamin E (300 mg/day) for 3 months. MDA levels in the untreated group, the EPO group and the EPO + vitamin E groups were found to be higher than the control group (p < 0.001, in both). Furthermore, MDA levels in both of the treatment groups were lower when compared to the untreated group (p < 0.001, in both). Plasma vitamin E levels in the untreated, the EPO group and EPO + vitamin E groups were lower than the control group (p < 0. 001). In contrast, plasma vitamin E levels in the treatment groups were higher in comparison with the control group (p < 0.05). SOD activities in the untreated, the EPO group and the EPO + vitamin E groups were found to be lower than the control group (p < 0.001). SOD activities in the treatment groups were higher than the control group (p<0.001). The SOD activities in the EPO+vitamin E group increased when compared to the EPO group (p < 0.001). CAT activities in the untreated, the EPO group and the EPO + vitamin E groups were found to be lower than the control group (p < 0.001 in untreated and EPO groups, p <0.01 in EPO+ vitamin E group). CAT activities in EPO and EPO+ vitamin E groups were increased when compared to the untreated group (p < 0.01). In conclusion, our findings have shown that antioxidant status decreased and lipid peroxidation increased in hemodialysis patients. EPO has an antioxidant effect on the RBC and plasma antioxidant status, and plasma lipid peroxidation. These effects were moderately increased by the combination of vitamin E and EPO.

Changes of antioxidant enzyme activities during cardiopulmonary bypass.

BACKGROUND: Reperfusion of ischemic heart causes the generation of free radicals, and these radicals play an important role in post-ischemic tissue damage. These free radicals are removed by scavenger enzymes and antioxidants in the cell. In this study, erythrocyte catalase, glutathione peroxidase and glutathione reductase enzyme activities were determined in patients undergoing cardiopulmonary bypass. EXPERIMENTAL DESIGN: Blood samples were obtained from the coronary sinus of patients at the following times: 1) Before cardiopulmonary bypass, 2) Immediately after cardiopulmonary bypass, 3) Fifteen minutes after the second specimen, 4) Thirty minutes after the second specimen. PATIENTS: this study was carried out on eleven patients undergoing open heart operation. MEASURES: catalase, glutathione peroxidase and glutathione reductase enzyme activities were determined in these patients. RESULTS. Catalase activity was significantly decreased in the third and fourth groups as compared with the first group, which was also the control group (p<0.05). Glutathione reductase activity in the third group was significantly higher as compared with control group (p<0.001). However, there were no differences in glutathione peroxidase activity among control group and other three groups (p>0.05). CONCLUSIONS: Our results indicate that the activities of antioxidant enzyme activities in erythrocytes are changed during the ischemia and reperfusion of the heart.

Effects of postmenopausal hormone replacement and alpha-tocopherol on the lipid profiles and antioxidant status.

Sixty-six postmenopausal women were randomly divided into three groups. The first group (n = 22) received transdermal oestradiol (0.05 g/day) for six months. Transdermal oestradiol was given during three weeks but was not given in the following week of each month during six months. In addition to the first group's therapy, medroxyprogesterone acetate (MPA; 10 mg/day, per orally) was administered to the second group (n = 22) for the last ten days. Vitamin E (600 mg/day, per orally) was given to the third group (n = 22) in addition to the first and second group therapy every day during six months. Total cholesterol, high density lipoprotein (HDL), very low density lipoprotein (VLDL) and low density lipoprotein (LDL) cholesterol, malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels of the three groups were measured at the beginning and at the end of therapy. In the transdermal oestradiol and transdermal oestradiol + MPA groups, post-treatment serum total, VLDL and LDL cholesterol levels decreased (P < 0.05) whereas HDL cholesterol level increased (P < 0.05). No significant difference was found in the levels of MDA, SOD and GSH-Px. In the third group, pre-treatment levels of total (P < 0.05), VLDL (P < 0.05), LDL cholesterol (P < 0.01) and MDA (P < 0.05) were high compared to post-treatment. Inversely, HDL cholesterol (P < 0.05) and vitamin E (P < 0.01) levels increased after the treatment. However, there was no significant difference in the levels of SOD and GSH-Px. In conclusion, in the post-menopausal period, because of the positive changes after hormone replacement plus vitamin E therapy, we suggest that hormone replacement and vitamin E combined therapy is effective in prevention of cardiovascular diseases.

The role of free radicals in p-aminophenol-induced nephrotoxicity: does reduced glutathione have a protective effect?

The role of free radicals in p-aminophenol (PAP)-induced nephrotoxicity and effects of reduced glutathione (GSH) were investigated. We injected PAP in one group of rats and PAP plus GSH in a second group. All parameters were measured in the renal tissue. Superoxide dismutase (SOD) activity in the PAP + GSH group (7.1 +/- 0.36 U/mg protein) was found to be significantly higher than in the control group (4.9 +/- 0.13) (P < 0.001). Catalase (CAT) was found to be significantly low in both groups (P < 0.001 in the PAP group (13.48 +/- 0.85 U/mg protein), P < 0.01 in the PAP + GSH group (18.75 +/- 1.17) as compared to the control group (41.03 +/- 0.93)). Glutathione peroxidase (GPx) in the PAP and PAP + GSH groups was found to be significantly high (P < 0.01 in the PAP group (5.32 +/- 0.033 U/mg protein), P < 0.001 in the PAP + GSH group (6.48 +/- 0.1)) as compared to the control group (2.93 +/- 0.093)). Similarly, glutathione reductase (GSSGR) in the PAP (0.023 +/- 0.002 U/mg protein), and PAP + GSH (0.025 +/- 0.001) groups was found to be significantly high as compared to the control group (0.014 +/- 0.001) (P < 0.001). GSH in the PAP (161.93 +/- 8.3 mg/mg protein) and PAP + GSH (170.7 +/- 4.51) groups were found to be significantly higher than the control group (104.91 +/- 3.0) (P < 0.001). Malondialdehyte (MDA) in the PAP (11.2 +/- 0.62 nmol/mg protein) and PAP + GSH (9.72 +/- 0.46) groups was found to be significantly higher than in the control group (5.54 +/- 0.51)(P < 0.001). Free radicals might have a major role in the PAP-induced nephrotoxicity. GSH increased nephrotoxicity.