The changes of spinal cord pathological and hindlimbs motor function of rats after decompression on chronic spinal cord injury

Objective To observe the spinal cord pathological change and hindlimbs motor function of rats after decompression on chronic spinal cord injury. Methods 30 Wistar rats were divided randomly into conrol group(n=5), compression group(n=5) and decompression group(n=20), then the decompression group was subdivided into 4 parts as 1 week, 2 weeks, 4 weeks, 6 weeks after decompression.Decompression was made after 30 days of chronic spinal cord copression injury, rats' motor function was detected by inclined plate experiment, the histopathological change, Nissl body and neural cells apoptosis in different spinal cord sections were assessed by the stainings of HE, Nissl and TUNEL. Results Compared with control group, the behavior testing showed all rats in compression group presented with weakness of muscle power in their hindlimbs(P<0.01), but the hindlimbs motor functions recovered from the first week after decompression and the difference had statistical significance compared with the compression group(P<0.01). Then the rats hindlimbs functions recovered gradually later on.The staining of HE, Nissl and TUNEL showed that the injured spinal cord section performed no improvement at the first 2 weeks after decompression, the neural apoptosis index(24.31±4.73)% decreased until the forth week after decompression(P<0.05). The spinal cord segments closed to the injured part recovered in early stage.At 1 week after decompression, lots of Nissl bodys were observed in spinal anterior horn, the neural apoptosis index in the 2 sections closed to the injured part were (15.21±4.81)% and (16.21±3.98)%, which declined observably compared with compression group(P<0.05). Conclusion After decompression on chronic spinal cord injury, the recovery of rats' hindlimbs motor function in early stage is probably benefited by the functional compensation of the spinal cord segments closed to the injured section. Key words: Chronic spinal cord injury; Motor function; Pathological change; Apoptosis