Changes in expression of ciliary neurotrophic factor (CNTF) and CNTF-receptor alpha after spinal cord injury.

To determine if ciliary neurotrophic factor (CNTF) is involved in the response to spinal cord injury, we studied changes in the expression of CNTF and that of its receptor, CNTF-receptor alpha (CNTFR alpha), in the rat spinal cord after a unilateral spinal cord hemisection. Using in situ hybridization, we found that CNTFR alpha mRNA levels in spinal cord motoneurons increased dramatically by 1 day after hemisecting the spinal cord at T2. This increase in expression was present only in motoneurons caudal, but not rostral, to the lesion. In addition, we detected increased levels of CNTF mRNA in the spinal cord white matter, also by 1 day following injury. Unlike CNTFR alpha, however, the increase in CNTF mRNA was evident both rostral and caudal to the lesion. Levels of both CNTF and CNTFR alpha mRNA declined between 1 and 5 days, and by 10 days they were not significantly different from normal animals. These findings suggest that CNTF may play a local role in the response to spinal cord injury.