ABSTRACT
In this study we examined the lobe-specific and age-dependent expression of Bcl-2 and Bax proteins, 80 male albino rats were used in this study, 20 rats were control 10 aged 4 month, and 10 aged 24 months, the rest of animals were divided into 3 equal groups each 20 animals half of them 4 months age and the rest 24 months age. The experimental groups were castrated, and were killed at 1, 10, 30 days after castration. Bcl-2 expression in the ventral lobe were lower compared with expression in the dorsal and lateral lobes respectively. Bax expression in the ventral lobe was higher than that in the lateral and dorsal lobes, respectively. In all three lobes, Bcl-2 was detected in epithelial cells, but not in stromal cells, where as Bax. protein was localized in both cell types. After castration, Bcl-2 expression in the ventral lobe decreased significantly from the control level shortly after castration, but increased significantly by 30 days. By contrast, Bax expression increased significantly, gradually decreased by time, and was nearly undetectable by 30 days post-castration. In the dorsal and lateral lobes, neither Bcl-2 nor Bax expression was significantly altered after castration. In the ventral lobe of old rats after castration, Bcl-2 followed a pattern of expression similar to that observed in young rats. However, Bax were lower in old rats compared with those in young rats after castration. Therefore, cell death follows the down-regulation of Bcl-2 expression in the ventral lobe of young and old rats. Moreover, the higher Bcl-2 expression in the dorsal and lateral lobes of controls and in the ventral lobe by 30 days after castration serve to protect cells from apoptosis. The conclusion of the study was that; the rat prostate lobes offer a model to study the molecular mechanisms of cell death and survival that are related to the androgen dependence of prostate epithelial ceils in normal and diseased conditions. The relative abundance of Bcl-2 and Bax proteins is critical in directing cells toward or away from apoptosis. The relative abundance of Bcl-2 protein correlates with the survival of prostatic epithelial cells. The age dependent decrease in cell death correlates with a reduced stimulation of Bax protein