Saussurea lappa root extract ameliorates the hazards effect of thorium induced oxidative stress and neuroendocrine alterations in adult male rats.

The present study was aimed to estimating the effect of Saussurea lappa (costus) root extract on thorium accumulation in different brain regions (cerebral cortex, cerebellum, and hypothalamus) of adult male albino rats and also to evaluate the antioxidant effect and thyroid gland modulation activity of costus following thorium toxicity. Adult male rats were randomly allocated into four groups; control group receiving saline (0.9% NaCl), thorium group receiving an intraperitoneal (i.p.) injection of thorium nitrate (Th; 6.3 mg/kg bwt), costus group receiving an oral administration of costus extract at 200 mg/kg bwt and costus + thorium group receiving costus 1 h before thorium injection. Thorium injection in rats for 28 days resulted in the accumulation of Th maximally in the cerebellum followed by the cerebral cortex and then in the hypothalamus. The accumulation of Th was associated with significant disturbance in sodium and potassium ions. A significant decrease in monoamines was also observed in different brain regions. Furthermore, the results indicated that Th-induced oxidative stress evidenced by increased lipid peroxidation and nitric oxide and decrease the glutathione content. Additionally, Th caused a significant increase in thyroid-stimulating hormone (TSH), triiodothyronine (T3), and thyroxine (T4) levels in the serum of rats. However, the pre-administration of costus alleviated all of those disturbances. Our results revealed that costus extract exerted its protective effect mainly through potentiating the antioxidant defense system.