Effects of Tongluo Recipe on experimental diabetic peripheral neuropathy in rats

OBJECTIVE: To investigate the effects of Tongluo Recipe (TLR), a compound Chinese herbal medicine, on experimental diabetic peripheral neuropathy in rats. METHODS: Diabetes was induced by streptozocin in rats. Eight weeks later, the diabetic rats were assigned to 3 groups according to different body weights: untreated group, low-dose TLR-treated group and high-dose TLR-treated group. Eight normal rats were assigned to normal control group. Systemic and sciatic nerve intrinsic antioxidant enzyme activities, lipid peroxide levels, hemorheology and sciatic nerve conduction velocity and ultrastructure changes were evaluated. RESULTS: Glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities were lower, and lipid peroxide levels were higher in plasma and sciatic nerve of the untreated group than those in the normal control group (P<0.05). Blood glucose and viscosity in the untreated group were higher than those in the normal control group. Sciatic nerve showed demyelination changes and decrease of conduction velocity. Vasa nervorum expanded and erythrocyte deposited in the capillary in the untreated group. TLR obviously improved sciatic nerve conduction velocity and ameliorated morphology changes, decreased blood viscosity, improved SOD and GSH-Px activities. CONCLUSION: TLR can obviously improve sciatic nerve function and ameliorate morphology changes in rats with diabetic peripheral neuropathy, probably through depleting free radical production, improving endothelial cell function and ameliorating hemorheology changes.