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Background: Smoking is associated with dysregulation of the antioxidant system and addiction., Aim: This study sought to ascertain the effect of Nigella Sativa (NS) oil on the antioxidant system, nicotine/tobacco addiction as well as the expressions of α4β2 nicotinic (nAChR) and dopamine type-2 (DRD2) receptors in selected brain regions of the rat., Methods: Thirty male Sprague-Dawley rats were divided into 6 groups comprising of vehicle-treated control, NS oil only, Smoke only, Smoke + NS oil, Nicotine only and Nicotine + NS oil. Animals were passively exposed to cigarette smoke or nicotine vapour for 12 weeks, however, NS oil treatment commenced from 9th-12th week of the experimental duration., Results: Nicotine vapour and cigarette smoke-induced increase in cotinine level were significantly ameliorated by NS treatment. Cigarette smoke or nicotine vapour exposure significantly (p<0.05) decreased the level of antioxidant enzymes while increasing malondialdehyde level in the brain homogenates of the rats.  Administration of NS oil significantly (p<0.05) reversed the reduced antioxidant level. Cigarette-smoke also significantly increased α4-nAChR expression in the frontal cortex and olfactory bulb compared to control. Nicotine vapour significantly increased DRD2 expression only in the olfactory cortex. NS oil administration reduced both the cigarette-smoke-induced increase in α4-nAChR and nicotine vapour-induced increase in DRD2 gene expression only in the olfactory cortex., Conclusion: Findings from this study suggest that NS oil improves brain antioxidant status while ameliorating nicotine vapour and cigarette smoke addiction through down-regulation of α4-nAChR and DRD2 gene expressions in discrete brain regions in Sprague-Dawley rats.

Background: Cisplatin is an anti-cancer drug that causes nephrotoxicity and oxidative stress. Extracts of Nigella sativa is nephroprotective. Vitamin E is also a potent antioxidant. This study sought to determine a possible synergistic effect of administering the two agents prior to cisplatin use on nephrotoxicity and oxidative stress., Methods: 48 male Wistar rats were randomly divided into 6 groups of 8 rats each. Group I served as the control. Group II received cisplatin without any treatment for 6 days. Groups III, IV, V and VI received 100 mg/kg Nigella sativa (NS), 200 mg/kg NS, 100 mg/kg Vitamin E and 200 mg/kg NS+100 mg/kg Vitamin E respectively for 5 days prior to 6 days administration of cisplatin. On the last day of the experiment, all the animals were sacrificed and serum samples collected for analysis., Results: Cisplatin administration caused a significant increase in creatinine level (p<0.01), urea level (p<0.01), sodium concentration and malondialdehyde level (p<0.001). Pre-administration with NS caused a significant reduction in creatinine level (p<0.001), urea level (p<0.001), sodium concentration (p<0.001) and malondialdehyde (p<0.01) level. Pre-administration with vitamin E caused a significant reduction in creatinine level (p<0.001), urea level (p<0.01), sodium concentration (p<0.001) and malondialdehyde level. They both also caused a significant increase in superoxide dismutase, reduced glutathione and catalase (CAT) levels. The combination of NS and vitamin E however did not show significant synergistic effects., Conclusion: These results suggest that even though pre-administration of the two agents protect against renal toxicity and oxidative stress, the effects are however not collaborative., Competing Interests: The authors declare that there was no conflict of interests., (© Georg Thieme Verlag KG Stuttgart · New York.)