[Effect of oxymatrine on apoptosis of hippocampal neurons by p38/JNK signaling pathway]

Abstract

To investigate the effect and mechanism of oxymatrine(OMT) on hippocampal neurons apoptosis. Effect of OMT on survival of hippocampal neurons was measured by MTT.Effect of OMT on LPS-induced lactate dehydrogenase(LDH) release rate in hippocampal neurons was measured by biochemical methods. Hoechst 33342 staining was used to observe the apoptotic morphology of hippocampal neurons.The mRNA expression levels of Bax, Bcl-2, and Caspase-3 were detected by Real-time quantitative PCR(RT-qPCR), and the protein expression levels of p38, p-p38, JNK, p-JNK, Bax, Bcl-2 and Caspase-3 were detected by Western blot.The results showed that, hippocampal neurons all grew well after treatment by different doses (0.37-6.0 g•L⁻¹) of OMT for 24 h. Stimulation from LPS increased the release of LDH(P<0.01), improved the JNK and p38 phosphorylation levels(P<0.01), increased the proportion of Bax/Bcl-2 and the expression of Caspase-3(P<0.01), and promoted the apoptosis of hippocampal neurons. OMT pretreatment could significantly reduce the release of LDH induced by LPS stimulation(P<0.05 or P<0.01), reduce the p38 and JNK phosphorylation, decrease the expression of Caspase-3 and Bax/Bcl-2(P<0.01), and diminish the apoptosis of hippocampal neurons.In conclusion, OMT could reduce the LPS-induced phosphorylation of p38 and JNK, down-regulate the Bax/Bcl-2 ratio and expression of Caspase-3, thus inhibiting apoptosis of hippocampal neurons. The mechanism may be associated with p38/JNK signaling pathway.

Keywords: apoptosis; hippocampal neurons; oxymatrine; p38/JNK.