The effect of Baicalein on hippocampal neuronal damage and metalloproteinase activity following transient global cerebral ischaemia.

Baicalein, a flavonoid derived from Scutellaria baicalensis Georgi, is known to protect neural tissue from damage. Several studies have found that baicalein reduces brain infarction following focal brain ischaemia. However, there are few reports on the protective effects of baicalein following global brain ischaemia. Therefore, the current study was designed to address the effects of baicalein on neuronal damage and matrix metalloproteinase (MMP; gelatinase) activity in the hippocampus after transient global ischaemia. C57BL/6 mice were subjected to transient global brain ischaemia for 20 min and sacrificed 72 h after ischaemic insult. Baicalein (200 mg/kg, once daily, as a suspension in 0.5% carboxymethylcellulose) or an equal volume of vehicle was orally administered to the mice from 7 days prior to the ischaemic insult until sacrifice. After global ischaemia neuronal damage was significant in CA1 and CA2 pyramidal cell layers. In baicalein-treated mice, neuronal damage from the ischaemic insult was significantly less than that in vehicle-treated mice. Baicalein administration also inhibited MMP-9 activity in the hippocampus. These data demonstrate that baicalein reduces hippocampal neuronal damage after transient global ischaemia. Besides its possible protective mechanisms, the protective role of baicalein against global ischaemia may operate, at least in part, through the inhibition of MMP-9 activity.