Effects of tramadol on serum β-endorphin,interleukin-4 and interleukin-10 in mice of formalin pain models

Objective This study was performed to evaluate the effects of tramadol IL-4,IL-10 and β-endorphin(β-EP) in mice of formalin pain models.Methods Total of ninty-one mice weighing 25-30 g were randomly divided into 4 groups:sham group(group S,n=28),tramadol group(group T,n=28),morphine group(group M,n=28)and control group(group C,n=7). Group S received an injection of 0.3 ml normal saline solution.Groups T and M received intraperitoneal injection 50 mg/kg tramadol or 5 mg/kg morphine.The pain scores during a period 60 min were recorded. The serum IL-4,IL-10 and β-EP concentrations were measured by enzyme-linked immunosorbent assay (ELISA)at 1 h,3 h,12 h,24 h after model making.Results Compared with group S,the pain scores at the phase II in groups M and T were significantly increased(P0.05),IL-4 at 24 h and IL-10 at 3,12,24 h after model making in group T were increased(P0.05). Compared with group M, β-EP at all the times in group T and 3,12,24 h after model making in group S were decreased(P0.05),also with the IL-4 at 3 h in groups T and S (P0.05),while IL-10 in group T at 3,12,24 h after model making were obviously increased (P0.05).Conclusion Both tramadol and morphine could exert satisfactory analgesic effect.Tramadol could alleviate the upregulation of serum β-EP and IL-4 induced by formalin injection