Flavonoids from Scutellaria attenuate okadaic acid-induced neuronal damage in rats

To study the effect of flavonoids isolated from aerial parts of Scutellaria baicalensis Georgi (SSF) on cerebral damage induced by okadaic acid (OA) in rats.OA was microinjected into the right lateral ventricle of male rats at a dose of 200 ng kg(-1) twice with a 3-day interval between injections to establish a model of Alzheimer's-disease-like cerebral damage. Neuronal morphology was observed with thionin staining and the expressions of glial fibrillary acidic protein (GFAP) and β-amyloid peptide 1-40 (Aβ1-40) were monitored via immunohistochemistry. The level of malondialdehyde (MDA) and the activities of glutathione peroxidase (GSH-Px) and lactate dehydrogenase (LDH) were measured using spectrophotometry.The results showed that OA-treated rats exhibited marked neuronal damage accompanied by increased levels of Aβ1-40 peptide and MDA accumulation, decreased GFAP protein expression and reduced GSH-Px and LDH activity in the brain. SSF at three doses (25, 50 and 100 mg kg(-1)) dramatically reversed the OA-induced changes in the brains of rats.SSF-mediated amelioration of OA-induced neuronal damage in rats provides a rationale for assessing SSF as a means of to reducing tau hyperphosphorylation and Aβ expression in the treatment of Alzheimer's disease.