Fig. 1.

MMP-9 enzyme activity (mean ± SEM) in C57/B6 mouse brain at 24 hr after trauma or sham operation. In sham-operated controls (n = 3), no constitutive MMP-9 activity was detected in the contralateral hemisphere. In the ipsilateral side, the craniotomy procedure alone appeared to induce a slight elevation in enzyme activity. However, this increase was not statistically significant (p = 0.16). In mice subjected to brain trauma (n = 5), MMP-9 activity was significantly higher in the traumatized hemisphere (*p < 0.05). Interestingly, however, MMP-9 enzyme activity was also significantly elevated in the contralateral side compared with that in the shams (p < 0.05).CCI, Controlled cortical impact.