Expression of apoptosis-related proteins in model of anoxia in vitro

There has been growing evidence that different modes of cell death exist, among them the apoptosis is thought to be an important mechanism of nerve cell loss implicated in various pathological states. A number of proteins mediated with apoptotic process have been identified, including p53, BAX, BCL-2 and BCL-X. We examined the expression of proteins related to programmed cell death in hippocampal neurons in vitro, exposed to pure anoxia or pretreated with apoptosis modulating agents: zinc and zinc chelator - TPEN. The results evidenced the noticeable differences in the expression of pro- and anti-apoptotic proteins in particular experiments. In the cultures exposed to pure anoxia, a significant increase of p53 and BAX immunoreactivity, associated with the decreased level of BCL-2 and BCL-X immunopositive cells was observed, related to the activation of apoptotic process. Hippocampal cultures pretreated with ZnCl2 before anoxia showed decreased immunoreactivity for p53 and BAX, connected with BCL-2 overexpression, whereas the cultures exposed to zinc chelating agent - TPEN or TPEN connected with anoxia showed significant increase of immunorectivity for p53 and BAX. This strong immunoreactivity of proapototic proteins (p53 and BAX) in hippocampal cultures exposed to anoxia or/and TPEN correlated with previous ultrastructural evidences of anoxia- and TPEN-induced apoptosis, while the overexpression of anti-apoptotic protein (BCL-2 and BCL-X) in zinc-pretreated cultures evidenced the protective ability of this metal against apoptosis in model of anoxia in vitro.