Effects of tramadol on serum NF-κB and IL-2 of mice with induced pain

Objective To investigate the influence of tramadol on the activation of nuclear factor-kappaB(NF-κB)and interleukin-2(IL-2) of mice with induced pain.Methods One hundred and twelve male BALB/c rats weighing 25-30 g were randomly divided into 4 groups with 28 rats each.Group C was taken as the control,group T was treated with tramadol 50 mg/kg,group M with morphine 5 mg/kg and group S with normal saline as sham operation group.Each group was divided into 4 subgroups of H1,H3,H12 and H24 according to the time of drawing blood sample.Blood was drawn from eye vein for determinations of serum NF-κB and IL-2 using ELISA.The paw-withdrawal latency to noxious thermal stimulation was measured using hot plate test.Results At T1-T4 the paw-withdrawal latency to noxious thermal stimulation was significantly higher in group T and M than that in group S(P 0.05).Compared with group S,there was a significantly increase at T2-T4 in group T in serum NF-κB levels (P 0.05).Compared with group C,there was a significantly increase in of group T in serum NF-κB levels at T4(P0.05),group M and S were significantly lower in serum NF-κB levels than those in group C at T3,T4(P0.05).There was a significantly increase in group T compared with group M in serum NF-κB levels at T2-T4(P0.05).Compared with group T,group M and S were significantly lower in serum IL-2 at T1-T3(P0.05).Compared with group S,there was a significant difference in group M in serum IL-2 levels(P0.05).Conclusion The activation of serum NF-κB and IL-2 was enhanced by tramadol but not by morphine suggesting that tramadol may induce an improvement of immunosuppression from pain.