The Effects Of Pentoxifylline On Neuropathic Pain Of Rats And TNF-α,IL-6 In Its Hippocampus

Objective To investigate the effect of pentoxifylline on MWT and TWL in neuropathic pain rats, and investigate the effect of pentoxifylline on cytokines in its hippocampus and their relationship with neuropathic pain.Methods Sixty-four adult male SD rats were randomly divided into four groups: group I,sham-operation group; group II,chronic constriction injury (CCI) group; group III,CCI with 50mg/kg pentoxifylline ;group IV,CCI with 100mg/kg pentoxifylline(n=16).Give intraperitoneal injection pentoxifylline or NS every day from the day before surgey to derived point, determined mechanical withdrawal threshold(MWT),thermal withdrawal latency(TWL)before preoperative 1d, postoperative 1d,3d,7d. Using Real-time fluorescence quantitative PCR to detect the expressions of TNF-α,IL-6mRNA in the right hippocampus after determination of behavior(n=8).Using immunohistochemistry to detect the expressions of TNF-α,IL-6 in the right hippocampus after determination of behavior(n=8).Results (1) Compared with the day before surgey, the MWT of group II,IIIand IV have significantly decrease in postoperative 1d,3d,7d(P<0.05).Compared with group I, the MWT ofⅡ,ⅢandⅣgroups postoperative 1d,ⅡandⅣgroups postoperative 3d,ⅡandⅢgroups postoperative 7d have significantly decrease(P<0.05).Compared with group II, the MWT ofⅢandⅣgroups postoperative 1d and 7d have significantly elevate (P<0.05). .Compared with groupⅢ, the MWT of groupⅣhave significantly elevate (P<0.05).Compared with the day before surgey, the TWL of group II,IIIand IV have significantly decrease in postoperative 1d,3d,7d(P<0.05).Compared with group I, the TWL ofⅡ,ⅢandⅣgroups postoperative 1d,ⅡandⅣgroups postoperative 3d,ⅡandⅢgroups postoperative 7d have significantly decrease(P<0.05). Compared with postoperative 1d, the TWL of groupⅢandⅣpostoperative 3d and 7d have significantly elevate (P<0.05). Compared with groupⅡ, the TWL of groupⅢandⅣpostoperative 3d and 7d have significantly elevate (P<0.05).(2) Postoperative 7d , compared with groupⅠ,the TNF-α,IL-6mRNA in the right hippocampus of groupⅡ,ⅢandⅣh ave significantly elevate(P<0.05). Compared with groupⅡ, the TNF-α,IL-6mRNA in the right hippocampus of groupⅢandⅣwas significantly lower (P<0.05).Compared with groupⅢ, the TNF-α,IL-6mRNA in the right hippocampus of groupⅣwas significantly lower (P<0.05).(3) Postoperative 7d , the immunocompetence of TNF-α,IL-6 in the right hippocampus of groupⅡ,ⅢandⅣh ave significantly elevate, showed that TNF-α, IL-6 positive cells and average optical density was significantly higher than in groupⅠ(P<0.05). Compared with groupⅡ, the positive cells and average optical density of TNF-α, IL-6 of groupⅢandⅣwas significantly lower (P<0.05).Compared with groupⅢ, the positive cells and average optical density of TNF-α, IL-6 of groupⅣwas significantly lower (P<0.05).Conclusions (1) Pentoxifyllin can inhibit mechanical allodynia and thermal hyperalgesia of rats when it were given intraperitoneal .(2) Pentoxifyllin can inhibit TNF-α, IL-6mRNA expression and TNF-α,IL-6 expression in immune activity of hippocampus induced by CCI, and high-dose have more effective than low-dose.