[Effect of clausenamide on the expression of Bcl-2 protein and apoptosis after focal cerebral ischemia/reperfusion in renovascular hypertensive rats].

Objective: To observe the effect and mechanism of clausenamide on the expression of Bcl-2 and apoptosis after focal cerebral ischemia/reperfusion in renovascular hypertensive rats.

Methods: Seventy-five renovascular hypertensive rats were randomly divided into three groups (25 in each group): clausenamide intervention group, single ischemia/reperfusion model group and sham-operated group. Focal cerebral ischemia was reproduced by ligature for 2 hours and loosening of the ligature in the rats. No arterial ligature was applied in sham-operated group. Computerized pathological image analyzer was used to determine the number of cells positive for Bcl-2 by immunohistochemical staining, and also the counts of apoptotic cells after TdT-mediated dUTP nick end labeling (TUNEL) staining respectively in coronal sections of brain after reperfusion (6, 12, 24, 48 and 72 hours).

Results: (1) The expression of Bcl-2 protein was detected 6 hours after reperfusion, peaking at 24 hours, then declined gradually. The Bcl-2 protein positive cell counts at every time point in clausenamide intervention group were significantly higher than simple ischemia/reperfusion model group (all P<0.01). (2) The number of apoptotic cells was increased with reperfusion, reaching its peak at 72 hours. The apoptosis counts in clausenamide intervention group were significantly lower than single ischemia/reperfusion model group (all P<0.01). At all time points, except at 48 hours after reperfusion, as there was no significant difference (all P>0.05). No Bcl-2 positive cells and only 0-2 apoptotic cells could be discernible in brain sections from sham-operated animals or in the contralateral side of ischemia in animals of the other groups.

Conclusion: Expression of Bcl-2 protein is enhanced and apoptosis appears after focal cerebral ischemia/reperfusion in rat brain. Clausenamide can enhance the expression of Bcl-2 protein and inhibit apoptosis remarkably. Clausenamide may coordinate with Bcl-2 in inhibiting apoptosis. This may be the mechanism of protection of brain cells from ischemic damage of clausenamide treatment.