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.