Effects of ciliary neurotrophic factor on the expression of glia fibrillary acidic protein in spinal cord injry in rats

Objective To study the effects of ciliary neurotrophic factor (CNTF) on the expression of glia fibrillary acidic protein (GFAP) mRNA and on the functional recovery after spinal cord injur in rats. Methods All the experimental rats were inflicted with spinal cord injury induced by Allen's weight dropping method. They were divided into group A in which the rats were treated with CNTF injection and group B in which the animals received heat inactivated CNTF injection. On the 1st,3rd,7th,14th and 28th day after the infliction of cord injury, the expression of GFAP mRNA was observed with in situ hybridization and immunocytochemistry. Quantitative analysis of the positive cells in the cord lesion and the adjacent area was performed with a computer image analysis system. The functional recovery of the spinal cord injury was examined with behavioral scores and electrophysiological technique. Results After cord injury, the expression of GFAP was significantly higher in group A than in group B. High expression of GFAP persisted to the 28th day after injury in group A and only to the 14th day in group B. The increase of the number of GFAP positive cells was correlated to the functional recovery of the spinal cord. Conclusion In spinal cord injury, CNTF can induce high expression of GFAP mRNA in cord cells and promote functional recovery of the cord.