Antioxidant and Chemopreventive Effects of Azadirachta indica on Lead Acetate-induced Hepatotoxicity in Male Wistar Rats.

Toxic metals such as lead (Pb) cause severe liver damage in humans and animals, with oxidative stress prominently implicated in the pathogenesis of lead acetate­induced liver injury. Azadirachta indica is hepatoprotective due to its antioxidative effect. This study investigated the antioxidative role of A. indica (AI) and its chemopreventive effect on lead acetate (LA)-induced hepatocellular dysfunction with seventy adult male rats classified into group A- Control (distilled water), group B 0.1% LA only, group C and D- 0.1% LA + 100 mg/kg and 0.1% LA + 200 mg/kg AI respectively, group E- 0.2% LA, group F and G- 0.2% LA + 100 mg/kg and 0.2% LA + 200 mg/kg AI. Oxidative stress markers (MDA and H2O2), antioxidant parameters (GSH, SOD, CAT, GPx, GST), inflammatory markers (MPO and NO), alanine aminotransferase (ALT) and histopathological studies of the liver were evaluated. The results showed that LA administration caused a decrease in GSH, GPx, and GST while AI co-administration increased the activities of the antioxidants. Moreover, LA administration increased MPO, NO, MDA, and H2O2 levels whereas AI significantly reduced (P<0.05) these parameters. Histopathological examination revealed necrosis and mild infiltration by inflammatory cells in LA administered rats, whereas these lesions were absent in AI administered rats. In conclusion, A. indica demonstrates a protective role in lead acetate-induced hepatotoxicity, mainly via oxidative stress inhibition.

Sodium arsenite-induced cardiovascular and renal dysfunction in rat via oxidative stress and protein kinase B (Akt/PKB) signaling pathway.

OBJECTIVES: Arsenic is a ubiquitous element that is widely distributed in the environment to which man and animals are exposed. Cardiovascular disease is one of the aftermaths of chronic arsenic exposure-related morbidity and mortality. This study sought to investigate the possibility of reversal from arsenic-induced cardio-renal toxicity following exposure and subsequent withdrawal. The study also seeks to understand the mechanism of action of this reversal. METHODS: Rats were orally exposed to sodium arsenite at 10, 20 and 40 mg/kg daily for 4 weeks followed by 4 weeks of withdrawal. RESULTS: Exposure to arsenic caused a significant increase in malondialdehyde, H2O2 generation but decrease total thiol and reduced glutathione levels in both cardiac and renal tissues. Furthermore, increases in superoxide dismutase, glutathione-S-transferase and catalase with significant increases in glutathione peroxidase activities were observed in the cardiac tissues. On the contrary, a significant reduction in the renal antioxidant enzyme activity was recorded following exposure. Also, antioxidant defense system did not return to apparent values after arsenic withdrawal. Immunohistochemistry revealed a reduction in the expression of the pro-survival protein-protein kinase B (Akt/PKB) following exposure to arsenic and this was not reversed by withdrawal Discussion: Exposure to arsenic caused cardio-renal toxicity via induction of oxidative stress and down-regulation of Akt/PKB expressions.

Sodium fluoride induces hypertension and cardiac complications through generation of reactive oxygen species and activation of nuclear factor kappa beta.

Human exposure to sodium fluoride through its daily usage is almost inevitable. Cardiovascular and renal dysfunction has been associated with fluoride toxicity. Therefore, this study investigated the mechanism of action of sodium fluoride (NaF) induced hypertension and cardiovascular complications Forty male albino rats of an average of 10 rats per group were used. Group A received clean tap water. Toxicity was induced in Group B to D by administering graded doses of NaF through drinking water ad libitum for 10 days at 150 ppm, 300 ppm, and 600 ppm concentration respectively. Following administration of NaF, there was significant increase in systolic pressure, diastolic pressure and mean arterial pressure. Markers of oxidative stress; malondialdehyde, hydrogen peroxide, advance oxidation protein products, and protein carbonyl were significantly increased in dose-dependent pattern in the cardiac and renal tissues of rats together with significant decrease in the GST activity in NaF-treated rats compared to the control. Also serum markers of inflammation, cardiac, and renal damage including myeloperoxidase, xanthine oxidase, blood urea nitrogen, creatinine, Lactate dehydrogenase (LDH), and Creatinine kinase myocardial band (CK-MB) significantly increased indicating induction of oxidative stress, renal, and cardiac damage after exposure. Histopathology of the kidney and heart revealed aberrations in the histological architecture in NaF-treated rats. Also, immunohistochemistry showed higher expression of nuclear factor kappa beta (NF-kB) in the cardiac and renal tissues of rats administered NaF. Combining all, these results indicate NaF-induced hypertension through generation of reactive oxygen species and activation of renal and cardiac NF-kB expressions. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1089-1101, 2017.