Rutaecarpine inhibits hypoxia/reoxygenation-induced apoptosis in rat hippocampal neurons.

Our previous studies showed that rutaecarpine (Rut) protected against myocardial ischemia/reperfusion (I/R) injury, which was associated with activation of transient receptor potential vanilloid subtype 1 (TRPV1). Recently, TRPV1 activation was also reported to exert neuroprotective effects. The present study was to investigate the effect of Rut on hypoxia/reoxygenation (H/R)-induced apoptosis in primary rat hippocampal neurons. Three-hour hypoxia (1% O2) and consequent 24-h reoxygenation significantly increased the apoptotic death of hippocampal neurons as evidenced by increases in both TUNEL-positive cell number and caspase-3 activity. However, pretreatment with Rut (1-10microM) or caspase-3 specific inhibitor DEVD-CHO could markedly attenuate H/R-induced apoptosis in neurons. Rut markedly induced the phosphorylation of Akt and PI3K inhibitor LY294002 prevented the survival effect of Rut on neurons. Intracellular oxidative stress was significantly induced after H/R, which was inhibited by Rut and LY294002 as well as antioxidant PDTC. TRPV1 antagonist capsazepine or intracellular Ca2+ chelator BAPTA/AM could abolish these effects of Rut mentioned above. In summary, the present data suggest that Rut inhibits H/R-induced apoptosis of hippocampal neurons via TRPV1-[Ca2+]i-dependent and PI3K/Akt signaling pathway, which is related to inhibiting oxidative stress and caspase-3 activation.