The Analgesic Effect Of Telmisartan On CCI Model In Rats

Part1Effect of Telmisartan on pain behavior in CCI ratsObjective To observe the effect of Telmisartan on pain behavior in CCI rats,and try to elucidate the role of angiotensin Ⅱ receptor in the nociceptive signaltransmission.Method Seventy-five male SD rats weighing230~270g were randomly dividedinto five groups as follows(n=15,each): group S, group C, group T2, group T5andgroup T10. In group S, sciatic nerves were exposed but not ligatured, and othergroups were set up with the mold of CCI. From the second day after operation,telmisartan2,5and10mg/kg(2ml) were fed to group T2, T5and T10respectivelyand normal saline2ml were fed to group S and C once a day for14days. Pawwithdraw thermal latency and paw withdraw mechanical threshold were measuredbefore CCI and3,7and14days after CCI in each groups.Result The paw withdraw thermal latency and paw withdraw mechanicalthreshold were significantly decreased in group C, T2, T5and T10compared withgroup S (P<0.05); The paw withdraw thermal latency and paw withdraw mechanicalthreshold were significantly increased in group T2, T5and T10compared with groupC (P<0.05); The paw withdraw thermal latency and paw withdraw mechanicalthreshold increased in group T5and T10compared with group T2(P<0.05); The pawwithdraw thermal latency and paw withdraw mechanical threshold were nostatistically significant difference between group T5and T10(P>0.05).Conclusion Telmisartan can alleviate paw withdraw thermal latency and pawwithdraw mechanical threshold of CCI rats, angiotensin Ⅱ receptor may contribute tothe CCI model. Part2Effect of Telmisatan on expression of TNF-α and p-Aktprotein in sciatic nerve of CCI ratsObjective To observe the effect of Telmisartan on expression of TNF-α andp-Akt protein in sciatic nerve of CCI rats, and explore the possible role of angiotensinⅡ receptors in the mechanisms of CCI rats.Method Seventy-five male SD rats weighing230~270g were randomly dividedinto five groups as follows(n=15,each): group S, group C, group T2, group T5andgroup T10. In group S, sciatic nerves were exposed but not ligatured, and othergroups were set up with the mold of CCI. From the second day after operation,telmisartan2,5and10mg/kg(2ml) were fed to group T2, T5and T10respectivelyand normal saline2ml were fed to group S and C once a day for14days. Five of ratsin each groups were sacrificed and extracted the sciatic nerves at the day before CCI,7and14days after operation, the expression of TNF-α in the ipsilateral sciatic nerveswere assayed with the Enzyme-linked immunosorbent assay (ELISA), the expressionof p-Akt were assayed with the Western blotting.Result TNF-α expression in the sciatic nerves were higher in group C, T2, T5and T10compared with group S (P<0.05); TNF-α expression were significantly lowerin group T2, T5and T10compared with group C (P<0.05); TNF-α expressiondecreased in group T5and T10compared with group T2(P<0.05); TNF-α expressionwere no statistically significant difference between group T5and T10(P>0.05). P-Aktexpression were higher in group C compared with group S (P<0.05); p-Akt expressionwere significantly lower in group T2, T5and T10compared with group C (P<0.05);p-Akt expression decreased in group T5and T10compared with group T2(P<0.05);p-Akt expression were no statistically significant difference between group T5andT10(P>0.05).Conclusion Telmisartan can reduce the TNF-α and p-Akt protein expressionlevels in sciatic nerve of CCI rats, angiotensin Ⅱ receptors may be involved in the formation of CCI model by regulating the expression of TNF-α and p-Akt.