Protective effects of baicalin on oxygen/glucose deprivation- and NMDA-induced injuries in rat hippocampal slices

Baicalin is a flavonoid derivative from Scutellaria baicalensis Georgi with various pharmacological effects. Recently, the neuroprotective effect of baicalin was reported. To confirm this effect and explore the possible mechanism, we have investigated the protective effect of baicalin on ischaemic-like or excitotoxic injury and the activation of protein kinase C alpha (PKC alpha) in rat hippocampal slices. In-vitro ischaemic-like injury was induced by oxygen/glucose deprivation (OGD) and the excitotoxic injury by N-methyl-D-aspartate (NMDA). The viability and swelling of the slices were detected by triphenyltetrazolium chloride (TTC) staining and image analysis of light transmittance (LT), respectively. The translocation of PKC alpha was measured by immunoblotting. Baicalin was added during both injuries. Baicalin (0.1, 1, and 10 mu mol L-1) concentration-dependently inhibited OGD-incluced viability reduction and acute neuron swelling, and inhibited the increased portion of PKC alpha present in the membrane fraction over the total PKC alpha. Baicalin ameliorated NMDA-induced viability reduction (not LT elevation) and inhibited the NMDA-increased membrane portion of PKC alpha at 1 mu mol L-1. We concluded that baicalin had a protective effect on ischaemic-like or excitotoxic injury in rat hippocampal slices, which might have been partly related to inhibition of PKC alpha translocation.