PERIPHERAL-NERVE REGENERATION THROUGH SILICONE CHAMBERS IN STREPTOZOCIN-INDUCED DIABETIC RATS

The silicone chamber model was used to evaluate peripheral nerve regen eration (PNR) in streptozocin (STZ)-induced diabetic rats. Diabetic an d control animals underwent sciatic nerve transection and silicone cha mber implantation establishing gaps of various lengths between the tra nsected nerve ends. In animals with 5 and 10 mm gaps, diabetes was ind uced in experimental rats I week before surgery, and the animals were sacrificed 3 weeks after surgery. In animals with 8 mm gaps, diabetes induction occurred 3 days after surgery, and they were sacrificed afte r 7 weeks. Diabetic rats with 10 mm gaps demonstrated an impaired abil ity to form bridging cables, the initial step of regeneration through chambers. Morphometric studies of bridging cables between transected n erve ends demonstrated a significant reduction in the mean endoneurial area in diabetic animals with 5 and 8 mm gaps compared to controls. T he number of regenerated myelinated axons in the chamber was significa ntly decreased in diabetic rats with 8 and 10 mm gaps, The mean myelin ated fiber area in the regenerated cables of the diabetic group was si gnificantly decreased with 5 mm gaps and significantly increased with 8 mm gaps compared to controls, Size-frequency histograms of regenerat ed myelinated fiber areas suggest a delay in the maturation of small c aliber axons, Schwann cell migration across 5 mm gaps was examined wit h S-100 immunohistochemistry. The total distance of Schwann eel migrat ion into cables from bath proximal and distal ends was significantly r educed in diabetic animals. Characterization of PNR across gaps throug h silicone chambers in diabetic rats showed impairment in multiple asp ects of the regenerative process, including cable formation, Schwann c ell migration, and axonal regeneration.