Baicalin protects neurons from oxidative stress and apoptosis induced by glutamate excitotoxicity in HT-22 cells

Abstract

Importance: Baicalin is a flavonoid compound with various functions, including neuroprotective effects. Glutamate is an essential excitatory neurotransmitter involved in synaptic transmission, but it can also induce neuronal damage through excitotoxicity. Objective: To analyze the anti-oxidant and anti-apoptotic effects of baicalin on glutamate-exposed neuronal cells. Methods: Mouse neuronal hippocampal HT-22 cells were cultured and treated with glutamate (5 mM) and/or baicalin (10, 30, 50 mu M). Baicalin was administered 1 h before glutamate treatment, and cells were collected 24 h following glutamate exposure. Reactive oxygen species (ROS) and lipid peroxidation (LPO) analyses were performed to determine the oxidative stress. Western blot and immunocytochemical staining were performed to investigate the expressions ofbcl-2, bax, and caspase-3. Results: Glutamate induced severe neuronal damage, including cell morphological condensation, which was attenuated by baicalin treatment. Baicalin treatment ameliorated the decrease in cell viability due to glutamate toxicity. Baicalin mitigated glutamate-induced increase of ROS and LPO in a dose-dependent manner. Glutamate exposure induced the downregulation of bcl-2 and the upregulation of bax, thereby reducing the bcl-2 to bax ratio, while administration of baicalin prevented these changes. Baicalin treatment ameliorated the glutamate toxicity-induced increase in caspase-3. Conclusions and Relevance: Baicalin exerts antioxidant and anti-apoptotic functions against glutamate toxicity in neurons by preventing oxidative stress and inhibiting the apoptotic pathway.