The effects of intraperitoneal TIIAS on the SNL-induced mechanical allodynia. SNL injury resulted in prominent mechanical allodynia. Intraperitoneal injection of TIIAS did not affect the pain threshold of the sham-operated group. Intraperitoneal administration of TIIAS (10 or 50 mg/kg, from days 3 to 10, once a day) significantly reduced SNL-induced mechanical allodynia in a dose-dependent manner, whereas 2 mg/kg TIIAS did not change SNL-induced mechanical allodynia (A). *P < 0.05, compared with that of the SNL-vehicle group. #P < 0.05, compared with that of the SNL-TIIAS (10 mg/kg) group. The dose-effect or log (dose)-effect curves for analgesic effects of TIIAS were shown in (B) and (C), n = 12 for each group. SNL, spinal nerve ligation; TIIAS, tanshinone IIA sulfonate; Veh, vehicle.