Propofol induces rat embryonic neural stem cell apoptosis by activating both extrinsic and intrinsic pathways

Propofol has previously been shown to have detrimental effects on the developing brain. Neural stem cells, identified in the embryonic brain as well as in the adult brain, are multipotent, self-renewing cells, which are capable of differentiating into different phenotypes of the nervous system. The present study was designed to investigate propofol-induced rat embryonic neural stem cell apoptosis and its potential mechanisms. Rat embryonic neural stem cells were isolated, cultured and characterized. Treatment of these cultured stem cells with different doses of propofol was carried out and cell proliferation was assessed by MTT assay and apoptosis by flow cytometric analysis. Cellular levels of active forms of caspase-3 and caspase-8, which regulate the extrinsic apoptotic pathway, and of caspase-9 and cytochrome C, which regulate the intrinsic apoptotic pathway, were detected by western blotting. Over 95% of isolated rat embryonic neural stem cells expressed the Nestin protein, as detected by immunofluorescence staining. Using an in vitro cell culture system, we showed that propofol inhibited cell growth and induced cell apoptosis in a dose-dependent manner. Furthermore, western blot analysis showed that propofol treatment significantly elevated levels of active forms of caspase-3, caspase-8, caspase-9 and cytochrome C in the embryonic neural stem cells. Propofol induced rat embryonic neural stem cell apoptosis and activated caspase-3, caspase-8, caspase-9 and cytochrome C, suggesting that propofol-induced stem cell apoptosis may be regulated through both the extrinsic and intrinsic apoptotic pathways.