Effect of subchronic exposure to arsenic on apoptosis of hippocampus cells in mice

Objective To examine the apoptosis of hippocampus cells in mice exposed to arsenic(As) subchronically and to provide evidences for exploring the mechanism of As-induced neurotoxicity.Methods Forty mice were divided into 4 groups of 10 each.Group 1 received drinking water alone(control).Group 2,3 and 4 received 1 ppm,2 ppm and 4 ppm As2O3 respectively.As2O3 was given through drinking water.On the 60th day after As2O3 exposure,mice were decapitated and the hippocampus was taken.Pathomorphological changes of hippocampus tissue were observed by optical microscope.Apoptosis of hippocampus cells was also examined by electron microscopy and TUNEL-Hoechst.Results Compared with control,swelling of hippocampus cells,sparse of cell distribution and disorder of cell arrangement where foswhd.Under transmission electron microscopy,some neurons in mice exposed to As showed a shrunken cellular membrane,diminished cell body and increased delectron density of nuclear chromatin.The apoptosis indices of the hippocampal neuron in the mice exposed to As were significantly higher than those in controls(P0.01).Conclusion The subchronic exposure to As may induce apoptosis of hippocampus cells in mice.