Fig. 3. Representative photomicrographs of cyclooxygenase 1 (COX-1) immunoreactivity at 24 h after surgery for the 2- and 4-week-old animals. The COX-1 immunoreactivity cells are less prominent in the 2-week-old spinal cord slices compared with the 4-week-olds. There is a clear difference in COX-1 immunoreactivity between the ipsilateral ( A ) and contralateral ( B ) spinal cord in the 4-week-old animals, whereas in the 2-week-old animals, there is no difference in immunoreactivity of the cells between the ipsilateral ( C ) and contralateral spinal cord ( D ).