Peripheral Nerve Regeneration at Two and Three Weeks After Crush Injury of Sciatic Nerves in Rat a Light Microscopic Study

In this investigation, structural differences were studied at the second and third weeks following crush lesion of sciatic nerves of adult female and male rats. The structural appearance of regenerating axons and myelin sheath were examined after crush injury. In order to compare nerve regeneration at two to three weeks, the left sciatic nerves were crushed at the sciatic notch. Two and three weeks later, both groups of rats were killed after fixation. The sciatic nerves were processed. The transverse sections of both groupÕs nerves were subsequently studied by light microscopy. This study included the entire 5mm distal portion of the crush site. The same level was sectioned in unoperated contralateral nerves, and these nerves served as controls. Two weeks after the crush, degenerating myelin, axonal debris, anhd macrophages in the distal stump were observed. Macrophages were identified as cells containing myelin debris. Growth into the distal injury zone was significantly less but started at the second week. Schwann cells provided myelination of fibers, and macrophages seem to phagocytose myelin sheath remnants that were increased at the second and third weeks after the injury macrophages and Schwann cells were more scarcer by the third week after injury, the disintegration of myelin remnants appeared to have been retarded. The results indicate that responses of neurons, axons, Schwann cell and macrophages could be important indications of the nerve regeneration at the 2 and 3 weeks.