Gene expression of inducible nitric oxide synthase in injured spinal cord tissue.

OBJECTIVE: To investigate gene expression of inducible nitric oxide synthase (iNOS) in injured spinal cord tissue of rats. METHODS: Thirty-six adult Sprague-Dawley rats were divided randomly into six groups: a normal group and five injury groups, six animals in ea ch group. Animals in the injury groups were killed at 2, 6, 12, 24, 48 hours after injury, respectively. A compression injury model of spinal cord was established according to Nystrom B et al, and gene expression of iNOS in spinal cord tissue was examined by means of reverse transcription polymerase chain reaction (RT-PCR). RESULTS: Gene expression of iNOS was not detectable in normal spinal cord tissue but was seen in the injury groups. The expression was gradually up -regulated, reaching the maximum at 24 hours. The expression at 48 hours began to decrease but was still significantly higher than that at 2 hours. CONCLUSIONS: iNOS is not involved in the normal physiological activities of spinal cord. Expression of iNOS is up-regulated in spinal cord tissue in response to injury and the up-regulation exists mainly in the late stage after injury. Over-expression of iNOS may contribute to the l ate injury of spinal cord.