Abstract： Objective:To explore the effect of lipoic acid capsule on diabetic peripheral neuropathy(DPN)in rats and initial mechanisms.Methods:Sixty healthy and non-specific pathogens level male rats with body weight(220±20)g were selected.The diabetic rat model was induced by intraperitoneal injection of the streptozotocin(STZ), and then 30 DPN model rats were randomly divided into model group, lipoic acid group and positive drug group according to the body mass random grouping method.At the same time, 10 normal rats were taken as the control group.The general condition of the rats before and after modeling were observed, and the blood glucose levels were measured before the modeling and at 2, 4, 8 weeks after modeling, the contents of malondialdehyde and glutathione in the sciatic nerve and the leves of sciatic nerve mechanical pain threshold and sciatic nerve conduction rate were determined after making the model for 8 weeks.Results:After 8 weeks of modeling, the control group rats have a better mental state, a slightly increased body mass, and a free activity.In the model group, rats gradually showed signs of malaise, polydipsia, polyphagia, polyuria, yellowish coat, weight loss, obvious bulging of the lower abdomen, crouching and hunched back after 3 days of injection of STZ.Symptoms gradually worsened with the increase of modeling time.The above signs were also present in the lipoic acid capsule treated group and the positive group rats, but the degree was lighter than the model group.The blood glucose levels in 2, 4, 8 weeks of model group were significantly higher than that of the control group, and the difference was statistically significant( P<0.001). The blood glucose levels in 4, 8 weeks of model group rats were higher than in 2 weeks of modeling, and the blood glucose levels of lipoic acid capsule treated group and the positive group were significantly lower than the model group.The difference was statistically significant( P<0.05). After 8 weeks of modeling, the level of malondialdehyde in the sciatic nerve of the model group was significantly higher than that of the control group, and the level of glutathione was significantly lower than that of the control group.The difference was statistically significant( P<0.01). The level of malondialdehyde in the sciatic nerve of the lipoic acid treated group and the positive drug group was lower than that of the model group, and the level of glutathione was higher than that of the model group.The difference was statistically significant( P<0.01). The mechanical pain threshold of rats in the model group was significantly lower than that of the control group after 4, 6, 8 weeks after modeling, and the difference was statistically significant( P<0.05). The mechanical pain threshold of the lipoic acid treated group and the positive drug group were higher than the model group at 6 and 8 weeks after modeling, the difference was statistically significant( P<0.05). The sciatic nerve conduction rate of rats in the model group, lipoic acid group and positive drug group were significantly slower than control group before treatment, and the difference was statistically significant( P<0.001). The sciatic nerve conduction rate of the lipoic acid treated group and the positive drug group were higher than the model group after treatment, and the difference was statistically significant( P<0.01). Conclusions:Alpha-lipoic acid can improve the nerve damage caused by DPN rats, and reduce the damage caused by oxidative stress while increasing the rate of nerve transduction.