Protective effect of ethanolic extract of Urtica urens L. against the toxicity of imidacloprid on bone remodeling in rats and antioxidant activities.

Imidacloprid (IMI) is very harmful to human health and cause problems. Recently, plants have been considered as potential agents for protection against these disorders. Urtica urens L. (UU) is very useful for relieving rheumatic pains and there is no scientific evidence justifying its use, which lets us think of its direct effect on the bone. This study aimed to investigate the protective effect of UU against toxicity effects of IMI in female rat. Rats were divided into control group, 3 groups treated with IMI at 50, 200 or 300mg/kg/day and 3 groups co-treated with IMI (50, 200 or 300mg/kg/day)+100mg/kg/day of UU. We studied bone remodeling through histological, histomorphometry and biochemical analyses. In IMI- treated groups, we have noted, following histomorphomotric analysis, significant decreases in cortical, trabecular thicknesses and osteoid surfaces. Elsewhere, IMI intoxication significantly decreased serum vitamin D and hydroxyproline levels in the groups treated for 60days. IMI intoxication increased significantly calcium, phosphorus contents, MDA and AOPP levels and the rate of calcification. It decreased significantly GSH, GPx, SOD, CAT, 17b-Estradiol and vitamin E levels, induces a tendency of rarefaction and increases of intrabecular spaces. The co-treatment with UU improved all biochemical parameters (hydroxyproline, MDA, AOPP, GSH, GPx, SOD, CAT, 17b-Estradiol, vitamin D, vitamin E calcium, phosphorus). UU leads to a significant increase in cortical, trabecular thicknesses, osteoid surfaces, a decrease in the intrabecular spaces and the rarefaction of bone. In conclusion, IMI inhibits bone remodeling and enhances bone formation. A significant antioxidant activity was also observed in UU and a total of 6 compounds were identified. Co-administration of UU provided a significant protection which might be due to its antioxidant property.