Effects of Nigella sativa L. and Urtica dioica L. on the numbers of mast cells in the thymus, spleen and mesenteric lymph nodes of rats with carbon tetrachloride toxicity

This study investigated the effects of Nigella Sativa L. (NS) and Urtica Dioica L. (UD) on the number of Mast Cells (MCs) in Carbon tetrachloride (CCl4)-treated rats. A total of 35 healthy male Sprague-Dawley rats were divided into 5 equal groups. All groups, expect control group, were injected subcutaneously with 0.8 mL CCl4 per kg body weight twice a week for 45 days and then CCl4 + UD-treated, CCl4 + NS-treated and CCl4 + UD + NS-treated rats received a daily intraperitoneal injection of 0.2 ml, kg(-1) NS or/and 2 mL kg(-1) UD oils for 45 days starting on day 46. Thymus, spleen and mesenteric lymph nodes were sampled, stained with 1% aqueous toluidine blue and examined microscopically. The thymus, spleen and lymph nodes of CCl4- exposed animals contained significantly increased numbers of MCs compared with control group, CCl4 + UD-treated, CCl4 + NS-treated and CCl4 + UD + NS-treated rats (p<0.05). However, when exposed rats were also treated with UD, NS or UD + NS, a decrease in MCs was observed. These results demonstrate that UD and NS decrease the number of MCs induced by CCl4 in the lymphoid tissues of rats.