The Study On The Neurocytic Apoptosis, NT-3 In Motor Cortex And Red Nucleus Of Rats Following Corticospinal Tract Lesion And Rubrospinal Tract Lesion

OBJECTIVES:1. To detect the changes of neurocytic apoptosis in the motor cortex and red nucleus of rats following corticospinal tract lesion and rubrospinal tract lesion.2. To detect the expressional changes of NT-3 in the motor cortex and red nucleus of rats following corticospinal tract lesion and rubrospinal tract lesion.3. To analyze if the changes of neurocytic apoptosis and NT-3 are corresponding with evolutionism:constitutions with inferior evolution have higher capability of recovery than those advanced.METHOD:The models of rats suffered dCST and RST transactions were used. Terminal deoxynucleotidyl-mediated nick end labeling (TUNEL) was used to detect the expression of neural apoptosis in both groups after operation (1,3,7,14 days).The expressions and changes of NT-3 were studied systematically by the methods of immunohistochemical staining in the same models.Results:1.TUNEL-positive cells stained by yellow and blue can be seen in the motor cortex and red nucleus, positive products located in the nucleus.There was a few number of TUNEL-positive cells were observed in motor cortex and red nucleus at 1 days postoperation, a great number of TUNEL-positive cells were observed in motor cortex and red nucleus at 3 days postoperation, and lasting to 14 days postoperation, the Apoptotic index of RST group is lower than dCST; presenting a significant increase compared with sham-operated control group (p＜0.05); The number of TUNEL-positive cells at 7 days postoperation is lower than 14 days.2. NT-3 immunoreactive cells were found in moto cortex layer V and red nucleus in both groups. The expression of NT-3 was increased gradually and reached the peak at 7 days postoperation in moto cortex, as well as at 3 days postoperation in red nucleus.Conclusion:1. Apoptosis of neural cells occurred extensively, it may be a main dead pattern in the secondary lesioned period after spinal cord injury.2. The results suggest that the demand of NT-3 increases in moto cortex and red nucleus after spinal cord injury and the increase of endogenous NT-3 may be beneficial for the survival and regeneration of the injured corticospinal and rubrospinal neurons.3. Group of RST transaction has less apoptosis of neural cells after injury, and the peak of the expression of NT-3 is earlier than group of dCST. This may imply that the RST has more power of recoverage ability than dCST.