Objective： To observe the deregulation of autophagy in diabetic peripheral neuropathy （DPN） and investigate whether Jinmaitong （筋脉通, JMT） alleviates DPN by inducing autophagy. Methods： DPN models were established by streptozotocin-induced diabetic rats and Schwann cells （SCs） cultured in high glucose medium. The pathological morphology was observed by the improved Bielschowsky＇s nerve fiber axonal staining and the Luxol fast blue-neutral red myelin staining. The ultrastructure was observed by the transmission electron microscopy. Beclinl level was detected by immunohistochemistry and Western blot. The proliferation of cultured SCs was detected by methylthiazolyldiphenyl-tetrazolium bromide. Results： Diabetic peripheral nerve tissues demonstrated pathological morphology and reduced autophagic structure, accompanied with down-regulation of Beclinl. JMT apparently alleviated the pathological morphology change and increased the autophagy [in vivo, Beclinl integral optical density （IOD） value of the control group 86.6 ± 17.7, DM 43.9± 8.8, JMT 73.3 ± 17.8, P〈0.01 or P〈0.05, in vitro Beclinl IOD value of the glucose group 0.47 ± 0.25 vs the control group 0.88 ± 0.29, P〈0.05]. Consequently, inhibition of autophagy by 3-methyladenine resulted in a time- and concentration- dependent decrease of the proliferation of SCs （P〈0.05, P〈0.01）. Conclusions： Down-regulation of autophagy in SCs might contribute to the pathogenesis of DPN. JMT alleviates diabetic peripheral nerve injury at least in part by inducing autophagy.
ABSTRACT Objective： To study the effects of the Chinese medicine Jinmaitong Capsule （筋脉通胶囊, JMT） on the pathomorphology of sciatic nerves, ciliary neurotrophic factor （CNTF）, and the mRNA expressions of CNTF in rats with streptozotocin-induced diabetes mellitus （STZ-DM）. Methods： The animal model was established by one time intraperitoneal injection of streptozotocin. The rats were simply divided by random into 5 groups including model group, low-dose JMT group （JL）, medium-dose JMT group （JM）, high-dose JMT group （JH） and neurotropin group. For each of the above 5 groups, a group of 10 normal Wistar rats matched in body weight, age and gender were set as normal group. Intragastric administrations were started after the animal model established. The JL group were administered with five times the JMT dose recommended for a human adult; the JM group were administered with ten times the JMT dose recommended for a human adult; the JH group were administered with twenty times the JMT dose recommended for a human adult. The neurotropin group was administered with ten times the neurotropin dose recommended for a human adult. All rats were given intragastric administration for 16 weeks and then killed. In the 4th, 8th, 12th, 16th week, body weight and blood glucose level were detected before and after the intervention. The morphologic changes of the sciatic nerves were observed by optical microscope and transmission electron microscope. The CNTF- mRNA expressions were detected by real-time fluorescent quantitative polymerase chain protein, and the CNTF protein expressions were detected by immunohistochemical method. Results： The blood glucose levels of the STZ-DM rats were much higher than normal group （P〈0.01）, and there was no apparent difference between any treatment groups and the model group （P〉0,05）. Before and after the intervention in the 4th, 8th, 12th, 16th week, there were no significant differences in the body weight among all the groups （P〉0.05）. The
Objective： To investigate the effect of Jinmaitong （筋脉通,JMT） serum on the proliferation of rat Schwann cells （SCs） primarily cultured in high glucose medium. Method： SOs were primarily cultured in Dulbecco＇s minmum essential medium （DMEM control）, 50 mmol/L glucose medium （50 mmol/L Glu）, 75 mmol/L glucose medium （75 mmol/L Glu）, as well as 50 mmol/L glucose medium, with different concentrations of JMT serum （undiluted, 1：2 diluted and 1：8 diluted） and Neurotropin （Ntp）, respectively. The proliferation of SCs under different conditions was detected by MTT. Result： SCs grew exuberantly in DMEM within 24-72 h, but slowed down at 96 h. The proliferation of SCs was inhibited in 50 mmol/L Glu and 75 mmol/L Glu after cultures of 48, 72 and 96 h, which showed that both were significantly different compared to the control group （P〈0.01）. The inhibition was more significant in 75 mmol/L Glu than in 50 mmol/L Glu （P〈0.05）. Spearman＇s rho analysis revealed that the proliferation of SCs had a negative correlation with the concentration of glucose （r=-0.471, P〈0.01）. Excluding the time factor, partial correlation showed similar results （r =-0.679, P〈0.01）. After 48 h, the proliferation of SCs increased significantly in JMT 1：2 and Ntp compared with 50 mmol/L Glu （control 0.437±0.019, 50 mmol/ L Glu 0.367±0.035, JMT1：2 0.426±0.024, Ntp 0.422±0.013; P〈0.01）, and there were no statistically significant differences among the JMT groups, the Ntp group and the control group （P〉0.05）. Conclusions： The proliferation of SCs was inhibited in high glucose medium, and the inhibition was reduced by different concentrations of JMT serum, especially at JMT1：2.
