MATERNAL DIESEL EXHAUST EXPOSURE INDUCES PATHOLOGICAL FINDINGS SIMILAR TO AUTISM IN NEWBORN MURINE BRAINS

Objectives: Diesel exhaust (DE) is a complex mixture of gases and DE particles (DEP). We have found neurobehavioral effects and fluctuation of neurotransmitters, which have a partial similarity to Autism, in the offspring of DE-exposure mice. In this study, we examined pathological effects on newborn brain by DEP-exposure to pregnant mice, especially focused on Autism.

Methods: ICR pregnant mice were exposed to DEP and some were exposed to clean air as a comparative control. Brain tissues (cerebral cortex, hippocampus and cerebellum) were obtained from the mice (housed in a clean air) born from DEP-exposure and control pregnant mice, and examined with light and electron microscope. To detect apoptosis in these tissues, the immunohistochemical staining for caspase-3 was performed, especially; the numbers of positive Purkinje cell in cerebellum were compared between DEP-exposure and control.

Results: In DEP-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 and degenerative changes were found in various cells (Scavenger cells, astrrocytes, endothelial cells etc.) in DEP-exposure group.

Conclusions: These findings indicate that DEP-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 DEPs is hazardous to fetuses' health and it is possible that these fetal damages carries a great risk of various disorders of nervous system afterward.