Apoptotic cell death in rat brain following deltamethrin treatment

In the present study we identified the degeneration and apoptotic cell deat h in rat brain after deltamethrin treatment. By hematoxylin-eosin (H&E) sta ining, a large number of degenerative cells (pyknosis of nuclei, disruption of eosinophilic cytoplasm) were seen in the hippocampus and cortex at 24 a nd 48 h after deltamethrin treatment at a dose of 12.5 mg/kg (i.p.) in corn oil. The similar morphological changes of degenerative cells were observed by cresyl violet staining. Numerous apoptotic cells were detected by in si tu end labeling (ISEL) and flow cytometric analysis in the hippocampus and cortex at 24 and 48 h following deltamethrin treatment at the same dose, wh ereas no ISEL-positive cells were seen in the same brain regions of control rats. Moreover, using DNA gel electrophoresis, it was demonstrated that DN A fragmentation was markedly induced in the hippocampus and cortex at 24, 4 8 and 72 h after treatment. In addition, the protein synthesis inhibitor cy cloheximide inhibited the DNA fragmentation elicited by deltamethrin in rat brain. These results indicate that deltamethrin induces degeneration and a poptotic cell death in rat brain, suggesting an important role played by ap optosis in neurotoxicity of deltamethrin. (C) 2000 Elsevier Science ireland Ltd. All rights reserved.