Protection of minocycline on early brain injury after subarachnoid hemorrhage in rats.

Minocycline has been shown to be neuroprotective in cerebral ischemia and in other models of brain injury. Our goal is to observe the protection of minocycline on EBI after SAH and the mechanism. 48 adult male SD rats were randomly divided into four groups: the sham-operated group, SAH group, vehicle group (SAH+normal sodium), and minocycline group (SAH+minocycline). The SAH model was induced by injecting 300 μl of autologous arterial blood into the prechiasmatic cistern. Expressions of MMP-9 in the hippocampus were examined at 24 h by western blot and zymography. Western blot and zymography showed that the expression of total and active MMP-9 increased dramatically at 24 h after SAH compared with that of the sham group (P<0.01). The clinical assessments got a lower score than that of the sham-operated group. After treated with minocycline, the expression of MMP-9 decreased significantly (P<0.01 vs. vehicle group), and the clinical assessments improved. We conclude that minocycline can protect EBI after SAH, which may be related to the mechanism of inhibiting the expression of MMP-9 in the hippocampus.