Expression and regulation of inducible nitric oxide synthase in spinal cord after acute spinal cord injury

Objective: To study the expression of inducible nitric oxide synthase (iNOS)expression and regulation of nuclear factor κB on iNOS in the spinal cord after acute spinal cord injury(SCI). Methods: With Allen's weight drop model, the injured or sham operation segments of spinal cord were dissected at different times after operation. Some of them were subjected to pyrrolidine dithiocarbamate (PDTC) after injury with a dose of 2, 20, or 200 mg·kg -1 . The quantity of iNOS mRNA and protein were determined by semi quantitative reverse transcription polymerase chain reaction or Western blot. The activation of NF κB was studied by EMSA. Results: The iNOS mRNA expression was observed from 6 to 24 hours post injury, and the highest was at hour 24. The expression of iNOS protein was increased 1 d 5 d after acute SCI, and peaked on day 3. The activation of NF κB was detected at hour 3 and increased with time. No decrement was observed until 24 h after SCI. The expressions of iNOS mRNA or protein were inhibited by PDTC dose dependently. Conclusion: Inducible NOS contributed to the secondary injury of acute SCI, and NF κB activation was involved in the expression of iNOS after acute SCI.