Deltamethrin induces altered expression of P53, Bax and Bcl-2 in rat brain

In this study we investigated the effects of deltamethrin on the expression of P53, Bar and Bcl-2 in rat brain. Immunohistochemical analysis demonstra ted that the immunoreactivity for P53 was markedly increased in the cerebra l cortex and hippocampus at 5 h after deltamethrin treatment, and maintaine d at an increased level at 24 and 48 h, whereas little immunoreactivity for P53 was seen in the same brain regions of control rats. The immunostaining for Bar was also elevated in the same brain regions, showing the same time course of P53 expression after deltamethrin treatment. However, the immuno labeling for Bcl-2 was markedly decreased at 24 h after a transient increas e at 5 h following deltamethrin treatment. These results indicate that delt amethrin leads to the persistent increase of P53 and Bar expression and tra nsient elevation of Bcl-2 expression, resulting in an increased ratio of Ba r to Bcl-2, which may contribute to apoptotic cell death in rat brain follo wing deltamethrin treatment. (C) 2000 Elsevier Science Ireland Ltd. All rig hts reserved.