Abstract: Objective To observe the difference between type 1 and type 2 diabetic peripheral neuropathy in rats induced by streptozotocin (STZ). Methods Male SD rats(10 rats in each group), common diet for 6 weeks to establish type 1 diabetes mellitus (T1DM) model by single intraperitoneal injection of STZ, and high fat and high sugar diet for 6 weeks to establish type 2 diabetes mellitus (T2DM) model by single intraperitoneal injection of 35 mg/kg 2%STZ. The normal control group (Con) is also established. The body weight, blood sugar were measured at different time. The mechanical withdrawal threshold was tested by electronic Von Frey instrument and hydrothermal tail-flick test was also conducted before death. The sciatic nerve pathology was examined. Results After 1st, 8th weeks of diabetes, compared with Con group and T2DM group, the body weight in T1DM group decreased significantly (P < 0.01).The blood glucoses in T1DM group and T2DM group were significantly higher than Con group (P < 0.01). DM Group the tail flick latencies in DM groups were longer than that of Con group (P < 0.01), and the numerical value in T2DM group was longer than that in T1DM group (P < 0.05). The threshold of mechanical pain in DM groups were significantly lower than that in group Con (P < 0.01), and the decrease in T2DM group was more obvious than that in T1DM group (P < 0.01). In DM groups, the myelinated nerve fibers in the sciatic nerve were arranged in disorder, with axonal swelling or shrinkage, uneven density of myelin sheath, vacuolar degeneration and partial myelination of nerve fibers. The degree of nerve damage in T2DM group was more severe than that of T1DM. Conclusion: The degree of peripheral neuropathy in type 2 diabetic rats induced by STZ is more severe than that of type 1 diabetic rats.

Key words: Diabetic peripheral neuropathy, Streptozotocin, Mechanical pain threshold, Hydrothermal tail-flick test, Pathomorphology