Lead (Pb) intoxication is a worldwide health problem which frequently affects the liver. This study was carried out to investigate the potential protective effect of thymoquinone (TQ), the major active ingredient of volatile oil of Nigella sativa seeds, against Pb-induced liver damage. Adult male rats were randomized into four groups: Control group received no treatment, Pb group was exposed to 2000 ppm Pb acetate in drinking water, Pb-TQ group was cotreated with Pb plus TQ (5 mg/kg/day, per orally), and TQ group receiving only TQ. All treatments were applied for 5 weeks. Results indicated that Pb exposure increased hepatic Pb content, damaged hepatic histological structure (necrotic foci, hepatic strands disorganization, hypertrophied hepatocytes, cytoplasmic vacuolization, cytoplasmic loss, chromatin condensation, mononuclear cell infiltration, congestion, centrilobular swelling), and changed liver function investigated by plasma biochemical parameters (AST, ALT, ALP, γ-GT, LDH). Pb treatment also decreased total antioxidant status level and increased lipid peroxidation in the liver. Supplementation with TQ remarkably improved the Pb-induced adverse effects without significantly reducing the metal accumulation in the liver. In conclusion, our results indicate, for the first time, a protective effect of TQ against Pb-induced hepatotoxicity and suggest that this component might be clinically useful in Pb intoxication.

This study was realized to investigate the possible beneficial effect of thymoquinone (TQ), the major active component of volatile oil of Nigella sativa seeds, against lead (Pb)-induced inhibition of rat testicular functions. Adult rats were randomized into four groups: a control group receiving no treatment; a Pb group exposed to 2000 parts per million (ppm) of Pb acetate in drinking water; a Pb-TQ group co-treated with Pb (as in Pb group) plus TQ (5 mg/kg body weight (b.w.)/day, per orally (p.o.)); and a TQ group receiving TQ (5 mg/kg b.w./day, p.o.). All treatments were for 5 weeks. No significant differences were observed for the body weight gain or for relative testes weight among the four groups of animals. Testicular Pb content significantly increased in metal-intoxicated rats compared with that in control rats. TQ supplementation had no effect on this testicular Pb accumulation. Interestingly, when coadministrated with Pb, TQ significantly improved the low plasma testosterone level and the decreased epididymal sperm count caused by Pb. In conclusion, the results suggest, for the first time, that TQ protects against Pb-induced impairment of testicular steroidogenic and spermatogenic functions. This study will open new perspectives for the clinical use of TQ in Pb intoxication.

ObjectiveAlteration of the antioxidant status in the kidneys may be related to lead (Pb) intoxication. The present study aimed to investigate the possible beneficial effect of thymoquinone (TQ), the major active ingredient of the volatile oil of Nigella sativa seeds, on Pb-induced renal antioxidant defense system impairment.MethodsA total of thirty two healthy adult male Wistar rats were randomly divided into four equal groups as follows: a control group, which received no treatment; a Pb group, which was exposed to 2,000 ppm of Pb acetate in drinking water; a Pb-TQ group, which was cotreated with Pb plus TQ (5 mg/kg/day, per os); and a TQ group receiving only TQ. All treatments were applied for five weeks.ResultsTQ alone did not induce any significant changes in the antioxidant defense system. By contrast, Pb exposure significantly decreased reduced glutathione level and superoxide dismutase, glutathione peroxidase, catalase, and glutathione reductase activities in the renal tissue. Interestingly, supplementation with TQ significantly improved the affected antioxidant parameters.ConclusionOur data are the first to provide evidence on the protective effect of TQ against Pb-induced renal antioxidant capacity impairment and suggest that this component might be a clinically promising alternative in Pb nephrotoxicity.

Alteration of the antioxidant system may be related to lead (Pb) hepatotoxicity. This study was carried out to investigate the possible beneficial effect of thymoquinone (TQ), the major active ingredient of volatile oil of Nigella sativa seeds, against Pb-induced liver antioxidant defense system impairment. Adult male rats were randomized into four groups: control group received no treatment, Pb group was exposed to 2000 ppm of Pb acetate in drinking water, Pb-TQ group was cotreated with Pb plus TQ (5 mg/kg/day, per os) and TQ group receiving only TQ. All treatments were applied for five weeks. TQ alone did not induce any significant changes in the enzymatic and non-enzymatic antioxidant status. By contrast, Pb exposure significantly decreased not only reduced glutathione level, but also superoxide dismutase, glutathione peroxidase, catalase and glutathione reductase activities in the liver tissue. Interestingly, when coadministrated with Pb, TQ significantly improved the affected antioxidant parameters. In conclusion, our results indicate a protective effect of TQ against Pb-induced liver antioxidant capacity impairment and suggest that this component might be a clinically promising alternative in Pb hepatotoxicity.

The purpose of the present study was to investigate the potential protective effect of thymoquinone (TQ), the major active ingredient of volatile oil of Nigella sativa seeds, against Pb-induced testicular oxidative stress. Adult male rats were randomized into four groups: control group which received no treatment, Pb group was exposed to 2000 ppm Pb acetate in drinking water, Pb-TQ group was co-treated with Pb plus TQ (5 mg/kg b.w./day, p.o.) and TQ group receiving only TQ (5 mg/kg b.w./day, p.o.). All treatments were applied for 5 weeks. Pb treatment induced oxidative stress status in testes as evidenced by a significant decrease in the antioxidant enzymes activities such as superoxide dismutase, glutathione peroxidase and catalase, and in the reduced glutathione content and in a significant increase in the level of malondialdehyde. Interestingly, TQ supplementation completely reversed these biochemical changes caused by Pb to the control values. In conclusion, our results suggest, for the first time, that TQ is very efficient in preventing Pb-induced testicular oxidative stress. This study will open new perspectives for the clinical use of TQ in Pb intoxication.