Abstract: Objective To evaluate the significance of molecular microenvironment in neurons for nerve regeneration and repair by investigating the dynamic changes of nerve regrowth-associated proteins following sciatic nerves crush in rats with streptozotocin-induced experimental diabetes. Methods Bilateral sciatic nerve crush was performed 4 weeks after induction of streptozotocin-induced experimental diabetes. the mean percentage of TUNEL positive cells in dorsal root ganglion(DRG) following bilateral sciatic nerves crush for 7 days, 14 days, 21 days, and 28 days, were evaluated. Immunohistochemical staining and Western-blot techniques were used to investigate the expression of nerve growth associated protein(GAP-43) and nerve growth factor receptor(trk A) in different duration following sciatic nerve crush injury. Results The percentage of TUNEL positive neurons in DRG significantly increased in all stages after sciatic nerve crush, reaching a peak at 14~21 days. The expression of GAP-43 and trk A in DRG were upregulated at all time points after nerve injury in streptozotocin-induced experimental diabetes, but the overall level was lower than that of non-diabetic rats. Conclusion In streptozotocin-induced experimental diabetes, neurons in DRG undergo survival crisis, the nerve regrowth-associated gene expression system was disintegrated, the capacity to regenerate their axons declines after nerve injury.

Key words: streptozotocin, diabetes mellitus, nerve injury, nerve growth associated protein, nerve growth factor receptor