Maternal Exposure to Diesel Exhaust Leads to Pathological Similarity to Autism in Newborns

We have already demonstrated many diesel exhaust particles (DEPs) and some damages in brain tissues (cerebral cortex and hippocampus) of newborn mice whose mothers inhaled DE during pregnancy, and these damages have the possibilities to lead to some disorders of nervous system. In this study, we examined pathological effects on newborn brain by DE-exposure to pregnant mice, especially focused on autism. ICR pregnant mice were exposed to DE and some were exposed to clean air as a comparative control. Brain tissues (cerebellum) were obtained from the mice (housed in a clean air) born from DE-exposure and control pregnant mice, and examined with light and electron microscope. To detect apoptosis, the immunohistochemical staining for caspase-3 was performed, especially; the numbers of positive Purkinje cell in cerebellum were compared between DE-exposure and control. In DE-exposure group, numerous caspase-3 positive cells were diffusely observed and the number of positive Purkinje cells was significant large than in control. Electron microscopically, specific features of apoptosis were found in Purkinje cells in the DE-exposure group. These findings indicate that DE-exposure to pregnant mice has a severe impact on fetal brain development and, especially, numerous apoptotic Purkinje cells cause the innate deficiency of them and would involve the pathogenic backing of autism. Our results would give a grave warning that the maternal inhalation of DE is hazardous to fetuses' health and it is possible that these fetal damages carries a great risk of various disorders of nervous system afterward, such as autism.