Reactive hyperplasia of glial cells induced by spinal cord injury in a rat model / 中国组织工程研究

ABSTRACT

BACKGROUND:The nervous reconstruction and repair after spinal cord injury have become a research hotspot. OBJECTIVE:To investigate the change rule of neurogliocyte reactive hyperplasia after spinal cord injury. METHODS:Forty-two adult male Sprague-Dawley rats were selected and equivalently randomized into seven groupsnormal control group (no intervention), sham operation group (lamina decompression) and operation groups (postoperative 1, 7, 14, 21 and 28 days). After the establishment of spinal cord injury models, the rats were sacrificed at each corresponding time point. The functional recovery of the rat hind limbs was evaluated by Basso, Beattie and Bresnahan scores, and complete spinal cord tissue was removed to undergo hematoxylin-eosin staining, immunohistochemistry staining and immunofluorescence staining. RESULTS AND CONCLUSION:(1) Basso, Beattie and Bresnahan scores showed that rats in the normal control and sham operation groups had normal neurologic function. Rats at 1 day after spinal cord injury paralyzed completely, the neurologic function of hind limbs began to recover gradual y at the 7th day, and the recovery became most obvious at the 14th day, which had no significant differences compared with the 21st and 28th days. (2) Hematoxylin-eosin staining found that the diffuse hemorrhage and neuronal necrosis were observed in the injured area at 1 day after operation;inflammatory cel infiltration and some vacuoles appeared at the 7th day, and the hemorrhage was absorbed gradual y;the hemorrhage disappeared completely and capsule cavity formed at the 14th day;up to the 28th day, spinal cord structure was completely destroyed and that was replaced by cicatricial tissue accompanying with a large cavity. (3) Immunohistochemistry staining showed that the astrocyte in damaged area proliferated with the cel synapse increasing, which was most overt at the14th day;the axon clearance widened and the structure was in disorder at the 7th day, and the myelin sheath in the damaged area was destroyed at the 21st day. (4) Immunofluorescence staining showed that there were numerous visible glial fibril ary acidic protein+/nestin+cel s in the injured area at 14 days after operation. (5) These results suggest that glial cel hyperplasia and hypertrophy, the up-regulated expressions of glial fibril ary acidic protein and nest protein are advantageous to the early repair of spinal cord injury.