Effects of maternal diazinon exposure on frontal cerebral cortical development in mouse embryo.

Background: Diazinon including organophosphate (OP) that is widely used in agriculture and animal husbandry industry and the risk of human infection with the toxin and their toxicity.

Methods: Pregnant balb/c mice (30-35 g) were randomly divided into five groups of five: the control group (no intervention), two sham groups (emulsifier 0.52, and 5.2 liters/volume). From the seventh to the eighteenth day of pregnancy, two experimental groups received diazinon inhaled 1.3 (EXP1) and 13 liters/volume (EXP2) for 40 min every other day, respectively. On the 18th day of pregnancy, the animals were killed and their embryos were removed to appraisal the growth of fetus and development of the frontal cortex. A computer-assisted morphometric quantitative images analysis were performed on the frontal cerebral cortex (FCC) including cortical plate (CP), intermediate zone (IZ) and matrix (proliferative) zone (MZ) of the mouse embryos.

Findings: The average of crown-rump length and weight of the embryos in the experimental groups were increased without any significant difference. The mean fetal FCC thickness in the EXP2 group was significantly reduced compared to the control group, CP thickness was remarkably increased in fetuses exposed to diazinon. Comparing the mean thickness of MZ and IZ in EXP groups with the sham and control groups indicated a significant decrease. The positive K-67 cells in the FCC of the EXP2 group were significantly reduced.

Discussion: Exposing diazinon during pregnancy can reduce brain development and would be neurotoxic to the developing brain and can lead to behavioral changes in the offspring.