Effects of salvianolic scid A on plantar microcirculation and peripheral nerve function in diabetic rats

Salvianolic acid A (SalA) is the main efficacious, water-soluble constituent of Salvia miltiorrhiza Bunge. This study evaluated the effects of SalA on plantar microcirculation and peripheral nerve dysfunction in streptozotocin (STZ )-induced type 2 diabetic rats. The rats were given a high-fat and high-sucrose diet for a month followed by intraperitoneal injection of STZ (30 mg/kg). Oral administration of SalA (1 and 3 mg/kg, respectively) was performed daily for 10 weeks after modeling. Diabetic rats were given a high-fat diet, while age-matched healthy rats were given a standard chow. Plantar microcirculation was measured by Laser Doppler flowmetry, and peripheral nerve function was measured with regard to pain withdrawal latency and motor nerve conduction velocity. The results show that the plantar blood perfusion and vasodilation reactivities decreased significantly, and latency of pain withdrawal and motor nerve conduction velocity rose in diabetic rats compared with the normal control group. SalA increased peripheral blood perfusion and vascular activities; improved peripheral nerve function; and decreased AGEs levels, vascular eNOS expression, and blood glucose, lipid, vWF and malondialdehyde levels in diabetic rats. The beneficial effects of SalA on plantar microcirculation and peripheral nerve function in diabetic rats might be attributed to improvements in lipid and glucose metabolism in diabetic rats, the inhibition of AGEs formation and the development of oxidative stress-related nervous and vascular damage. Based on these findings, we proposed that therapeutic use of SalA to prevent the development of diabetic foot problems.