Experimental study on the relationship between substantia nigral apoptosis and expression of Bax protein in Parkinson disease

Objective To determine whether 6-hydroxydopamine (6-OHDA) evoke apoptosis of substantia nigra and whether apoptosis involved in the pathogenesis of Parkingson disease and observe the relationship between substantia nigral apoptosis and expression of Bax protein.Methods Using TdT-mediated biotinylated-dUTP nick end labeling methed(TUNEL),in situ hybridization and electron microscopic techniques,We observed the number of nigral apoptosis and the changes of ultrastructure in the course of the formation of Parkinson disease models in rats(PD group),that is 1 d,7 d,14 d,21 d after 6-OHDA was injected stereotaxically to right side of the mesencephic ventral tegmental area(VTA) and substantia nigra pars compacta(SNc) of rats.At the same time, Bax protein were measured.Results The number of substantia nigral apoptosis in the PD group is much more than that of the control group, and from 1 d to 21 d the number of substantia nigral apoptosis is increased gradually.In the PD group the ultrastructure of substantia nigra exhibited morphological characteristics of apoptosis,including chromatin condensation, membrane blebbing, internucleosomal DNA fragmentation,which aggravated successively.Bax protein attained the peak value promptly at 1 d,and then decreased gradualy.Bax protein in the PD group exceeded that of the control group.Conclusions Apoptosis of substantia nigra can be evoked by 6-OHDA.Apoptosis of substantia nigral induced by 6-OHDA contributes to the pathogenesis of PD .As a key evoking factor,Bax protein involves in pathogenesis of Parkinson disease.