Dual-direction effect of crenulatin on apoptosis of cerebral microvascular endothelial cells and it's mechanism

)［ABSTRACT］AIM: To study the effect and the mechanism of crenulatin, an effective constituent of Chinese traditional medicine, on apoptosis of cerebral microvascular endothelial cells. METHODS: The following terminal concentrations of crenulatin were used in the study: 25 mg/L and 100 mg/L. Apoptosis of mouse cerebral microvascular endothelial cells (bEnd.3 cell line) was evaluated by flow cytometer, immunocytochemical assay (Fas, Bcl-2) and Western blotting (caspase-3) after culture for 24 h. RESULTS: Compared with control group, apoptosis of bEnd.3 cells in 25 mg/L group was significantly inhibited (P<0.05), but apoptosis in the 100 mg/L group was significantly increased (P<0.05). In apoptosis inhibited group, the Fas immunocytochemical staining was weaker, the positive cells were significantly decreased (P<0.05) and caspase-3 expression was decreased compared with control group; however, the Bcl-2 staining was stronger and the positive cells were significantly increased (P<0.05). On the other hand, in apoptosis increased group (100 mg/L group), the changes were just opposite. CONCLUSIONS: The effect of crenulatin on apoptosis of mouse cerebral microvascular endothelial cells possesses a dual-direction change, inhibitive effect in 25 mg/L and stimulative effect in 100 mg/L group, respectively. The mechanism is related to the alterations of Fas/Bcl-2 expression and caspase-3 activity.