Protective Effects of Polygala on Sciatic Nerve of Diabetic Peripheral Neuropathy Rats

Objective To investigate the protective effects of Polygala on sciatic nerve of diabetic peripheral neuropathy(DPN) rats.Methods Male Wistar rats were randomly divided into 4 groups(n=12):normal control group,DPN model group,Polygala treatment group and Polygala prevention group.The rats in DPN model group,Polygala treatment group and Polygala prevention group were made diabetes model by injecting streptozocin intraperitoneally.After the diabetes model was established,the rats in Polygala prevention group were lavaged with Polygala(2.7 g·kg-1·d-1)for six weeks.The rats in DPN model group and Polygala treatment group were made DPN model when their caudal sense nerve conduction velocity(SNCV)was less than 30 m/s;then the rats in Polygala treatment group were lavaged with Polygala(2.7 g·kg-1·d-1)for six weeks.The caudal SNCV of rats in each group were respectively detected;Aldose reductase(AR)activity was detected by ultraviolet spectrophotometry and immunohistochemical staining was used to observe the expression of neurofilament protein(NFP) in sciatic nerve.Results Compared with normal rats,the caudal SNCV of DPN model rats decreased obviously,AR activity of sciatic nerve increased markedly and NFP expression decreased obviously(P0.01).Compared with DPN model rats,the caudal SNCV of rats in Polygala treatment group and Polygala prevention group obviously increased,AR activity of sciatic nerve decreased markedly and NFP expression obviously(P 0.01,P 0.05)increased.Conclusion Polygala has protective effects on DPN rats sciatic nerve by improving caudal SNCV,decreasing AR activity and up regulating NFP expression in sciatic nerve;moreover,Polygala pretreatment has preventive effects on sciatic nerve injury of diabetes rats.