Effects and mechanism of Weinaokang on reperfusion-induced vascular injury to cerebral microvessels after global cerebral ischemia.

OBJECTIVE

To study the effects of the Weinaokang (WNK), the active compounds extracted from Ginkgo, Ginseng, and saffron, on ischemia/reperfusion (I/R)-induced vascular injury to cerebral microvessels after global cerebral ischemia.

METHODS

Male C57BL/6J mice were randomly divided into 5 groups (10 animals/group): the sham group (0.5% CMC-Na, 20 mL/kg), the I/R model group (0.5% CMCNa, 20 mL/kg), the I/R+Crocin control group (20 mg/kg), the I/R+high dose WNK group (20 mg/kg), and the I/R+low dose WNK group (10 mg/kg). Bilateral common carotid artery occlusion (BCCAO, 20 min) in mice, followed by 24 h reperfusion, was built. The generation of nitric oxide (NO), the activity of nitric oxide synthase (NOS), the phosphorylation of extracellular signal-regulated kinase1/2 (ERK1/2), and the expression of matrix metalloproteinases-9 (MMP-9) and G protein-coupled receptor kinase 2 (GRK2) in cortical microvascular homogenates were evaluated. The ultrastructural morphology of cortical microvascular endothelial cells (CMEC) was observed.

RESULTS

The transient global cerebral ischemia (20 min), followed by 24 h of reperfusion, significantly promoted the generation of NO and the activity of NOS. The reperfusion led to serious edema with mitochondrial injuries in the cortical CMEC, as well as enhanced membrane GRK2 expression and reduced cytosol GRK2 expression. Furthermore, enhanced phosphorylation of ERK1/2 and decreased expression of MMP-9 were detected in cortical microvessels after I/R (20 min/24 h). As well as the positive control Crocin (20 mg/kg, 21days), pre-treatment with WNK (20, 10 mg/kg, 21 days) markedly inhibited nitrative injury and modulated the ultrastructure of CMEC. Furthermore, WNK inhibited GRK2 translocation from cytosol to the membrane (at 20 mg/kg) and reduced ERK1/2 phosphorylation and MMP-9 expression in cortical microvessels.

CONCLUSIONS

WNK and its active compounds (Crocin) are effective to suppress I/R-induced vascular injury to cerebral microvessels after global cerebral ischemia with the target on GRK2 pathways.