The Study Of Cytokines On The Spinal Dorsal Horn Of The Neuropathic Pain Rats Imposed By Emodin

ObjectiveIn the view of a balance between the pro-cytokines and anti-cytokines,this study aim to explore the analgesia effect of emodin on neuropathic pain rats and the change of IL-1?,TNF-? and IL-10 on the spinal dorsal horn of the chronic contraction injury model.Methods162 male SD rats were randomly divided into six groups: sham group(S group),chronic contraction injury model group(C group),high dose of emodin group(H group,100 mg/kg),middle dose of emodin group(M group,50 mg/kg),low dose of emodin group(L group,25 mg/kg),pregabalin group(P group,15 mg/kg).From the 1st day after the operation,rats were treated with emodin and pregabalin as designed respectively by intragastric administration everyday,except the sham group.All of the rats were tested mechanical withdrawal threshold(MWT)and paw withdraw thermal latency(PWL)at 2nd day before the operation and the 3rd,7th,11 th,15th day after the operation.At the 3rd,7th and 15 th day,the spinal cord of rats in each group were took out to detected the expression of IL-1? ?TNF-? and IL-10 by western blot and qPCR.Results1.Before the operation,there was no significant difference among MWT and PWL of rats in the six groups.At the 3rd day after operation,MWT and PWL of C group were much lower than S group significantly(P<0.05).The 7th day after,MWT and PWL of every treatment group were higher than C group significantly(P<0.05).The 15 th day after operation,compared with C group,MWT and PWL of treatment group elevated remarkably(P<0.01).And there was no significant difference of MWT among the three emodin groups to the P group(P>0.05),but only the PWL of M group was closed to the P group(P>0.05).2.The expression of target protein: At the 3rd day after operation,IL-1? ?TNF-? of C group were remarkably higher than S group(P<0.05)and compared with C group,IL-1? of P group decreased and L group elevated(P<0.05).The 7th day after,IL-1? of C group increased and IL-10 decreased which compared with S group(P<0.05).IL-1? of L group was lower than C group markedly(P<0.05),furthermore IL-10 of M group and L group were higher than C group markedly(P<0.05).The 15 th day after,IL-1? of C group was still higher than S group significantly(P<0.05),while IL-1? of M group and L group were much higher than C group(P<0.05).In addition,TNF-? in H group,M group and L group didn't obviously changed compared with C group(P>0.05).3.The expression of mRNA: At the 3rd day after operation,IL-1? and TNF-? increased significantly compared with S group(P<0.05)and IL-1? P group reduced significantly compared with C group(P<0.05).At the 7th day after operation,compared with S group,IL-1? of C group elevated markedly(P<0.05)and IL-10 reduce conversely(P<0.05).Besides,IL-1? of L group and P group decreased remarkably(P<0.05).At the 15 th day after operation,IL-1? of C group was significantly higher than S group(P<0.05).In all of H group,M group,L group and P group,IL-1? was obviously lower than C group(P<0.05).There were some extent decline of TNF-? in H group,M group and L group compared with C group.Conclusion1.Combined the result of MWT and PWL,It's consider to be definite that emodin can alleviate the hyperalgesia and allodynia of neuropathic pain rats.Among the three dosages,the middle dose of emodin has the best effect,especially the improve of the heat hyperalgesia,which was closed to the positive drug pregbalin.2.In the case of the comparison among different doses emodin groups,middle doses and low doses can elevate the anti-inflammation effect dramatically.But it's doubtful that the low doses emodin may aggravate the inflammation at the early time of CCI.Therefore,this study considers that the effect of middle doses of emodin more remarkably and more definitely,which was also more correspond to the behaviors outcome.Pregbalin,as the first-line treatment,has the effect of anti-inflammation to some extent.3.In the study,emodin shows the ability of regulating the balance between pro-inflammation and anti-inflammation.And in the case of time,emodin conduct the alleviation from the 7th to the 15 th,contributed to the elevation of IL-10 an the reducing of IL-1?.Though there were some degree decrease,emodin can depress the expression of TNF-? with insufficient evidence.