RESUMO
OBJECTIVE To investigate the impacts of andrographolide on sciatic nerve function injury in diabetic peripheral neuropathy （DPN） rats by regulating high-mobility group protein box 1 （HMGB1）/receptor for advanced glycation end products （RAGE） signal pathway. METHODS A total of 84 rats were randomly divided into the control group （normal saline）， DPN group （normal saline）， low-dose andrographolide group （0.833 mg/kg）， high-dose andrographolide group （3.332 mg/kg）， lipoic acid group （positive control， 0.1 g/kg）， recombinant rat HMGB1 protein （rHMGB1） group （8 μg/kg）， and high-dose andrographolide+ rHMGB1 group， with 12 rats in each group. All rats except those in the control group were fed with high glucose and high fat diet combined with intraperitoneal injections of streptozotocin to establish the DPN rat model. After 24 hours of successful modeling， medication was administered daily for 8 weeks. The changes in fasting blood glucose， mechanical pain threshold， heat pain threshold and sciatic nerve conduction velocity were detected. Pathological changes in the sciatic nerve of rats and the activity of superoxide dismutase （SOD） and the content of malondialdehyde （MDA） in the sciatic nerve of rats were also detected. Besides， the expressions of HMGB1， RAGE proteins and phosphorylation level of nuclear factor κB p65（NF-κB p65） protein in rat sciatic nerves were found. RESULTS Compared with the control group， the pathological damage of the sciatic nerve of rats in the DPN group was strengthened， the fasting blood glucose， heat pain threshold， MDA content and the 诊治。E-mail：dqiaur@163.com expressions of HMGB1， RAGE proteins and phosphorylation level of NF-κB p65 protein were increased （P＜0.05）， while the mechanical pain threshold， sensory nerve conduction velocity， motor nerve conduction velocity， and SOD activity were decreased/slowed down （P＜0.05）. Compared with the DPN group， the above indexes were significantly potentiated in the andrographolide low- and high-dose groups and lipoic acid group （P＜0.05）， and the corresponding trends in the rHMGB1 group were opposite to those in the above three administration groups （P＜0.05）. Moreover， rHMGB1 attenuated the hypoglycemic effect of high-dose andrographolide on blood glucose and the improvement of oxidative stress injury in the sciatic nerve of DPN rats （P＜0.05）. CONCLUSIONS Andrographolide may reduce blood glucose by inhibiting the HMGB1/RAGE pathway and oxidative stress， thus ameliorating sciatic nerve injury in DPN rats.