Effects of LPS treatments on lymphoid organ indexes of SD rats. A – spleen weight, B – thymus weight, C – the ratio of spleen to body, D – the ratio of thymus to body. The following symbols indicates significant changes in lymphoid organ indexes (P < 0.05): * spleen and thymus differences between LPS and control group on the same days, $ – LPS treatment for day 29 versus LPS treatment for days 32, 35, and 38, # – LPS treatment for day 32 versus LPS treatment for days 35 and 38, % – LPS treatment for day 35 versus LPS treatment for day 38