Effect of active fraction from Huanglian Jiedu Decoction on activation of astrocytes and expression of Cx43 in cerebral ischemic penumbra Effect of apigenin on microglia in penumbra after acute transient focal cerebral ischemia-reperfusion injury in rats Effect of apigenin on microglia in penumbra after acute transient focal cerebral ischemia-reperfusion injury in rats