Neuroprotective effects of the Chinese Yi-Qi-Bu-Shen recipe extract on injury of rat hippocampal neurons induced by hypoxia/reoxygenation

Objective

To explore the protective effects of the Chinese Yi-Qi-Bu-Shen recipe (YB) against neuronal injury induced by hypoxia–reoxygenation, which has shown beneficial effect in improving the brain function of type 2 diabetics likely through its antihyperglycemic, antioxidant activity, and investigate its mechanisms.

Methods

The bilateral hippocampus was collected from newborn rats to establish single cell suspension. On the 10th day, the primarily cultured hippocampal neurons were randomly divided into five groups: the normal group (NG), the hypoxia/reoxygenation group (HG), and groups protected with small, medium and large dosages of YB (SG, MG and LG, respectively). The YB-protected groups were treated with different concentrations of YB containing serum before reoxygenation. The metabolic rate of MTT, the malondialdehyde (MDA) content, and the activity of superoxide dismutase (SOD) and lactate dehydrogenase (LDH) were measured with assay kits. The apoptosis rate of hippocampal neurons were tested using flow cytometry analysis. RT-PCR was used to evaluate the mRNA expressions of bcl-2 and bax genes.

Results

The SOD activity, the cell survival rate, the bcl-2/bax ratio, and the bcl-2 mRNA expression in the HG group were significantly lower (all P<0.01), but the levels of MDA and LDH, the apoptosis rate, and the bax mRNA expression were higher (all P<0.01) than those in the NG group. The SOD activity, the cell survival, the bcl-2 mRNA expression, and the bcl-2/bax ratio were significantly higher in all of the YB-protected groups (all P<0.01), but the level of MDA and LDH, the apoptosis rate, and the bax mRNA expression were lower (P<0.01, P<0.05) than those in the HG group in a dose dependent manner.

Conclusion

The YB extract has a protective effect on hippocampal neurons against injury induced by hypoxia/reoxygenation, through its antioxidant activity and the regulation of apoptosis.