Kobra Afsordeh - Department of Biology and Anatomy, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Yousef Sadeghi - Department of Biology and Anatomy, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Abdollah Amini - Department of Biology and Anatomy, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Zahra Namvarpour - Institute for Cognitive Science Studies (ICSS), Tehran, Iran

There is much evidence that indicates the effect of heavy metals on neuro-immune cells, which lead to neurogenic inflammatory responses. In this study, the immune cells (mast cells (MCs), and microglia), and the pro neuroinflammation cytokines (Interleukin-1b (IL-1b) and Tumor Necrosis Factor-α (TNF-α)) were assessed in the prefrontal lobe of rat brain exposed to Thimerosal (49.55% ethyl-mercury by weight) indifferent timeframes. Materials and Methods: 108 neonatal Wistar rats were divided into three groups with three subgroups : 1) The experimental groups taked a single dose of Thimerosal (300μg/kg) on postnatal days 7, 9, 11and 15. 2) The Vehicle groups receivedPBS (Ph. =7.4) on the same order and 3) The control groups received nothing. The samples of the prefrontal cortex were collected and prepared for soteriological, Immunohistochemistry and molecular studies at different timeframe including 12h, 48h (as acute phases), and 8 days (as subchronic phase) after the last injection, respectively. Results: The average density of microglial and mast cells was significantly increased in experimental groups. This increase was more dominant in 48 h. In 8 days after injection, there was a significant decrease in density of mast cells in compared with 12h and 48h. Alterations of pro inflammatory cytokines were significant in all timeframes. This increase was more dominant in 48h after last injection and also, there was a significant decrease in both neuro- inflammatorycytokines after 8 days. Conclusion: Ethyl-mercury led to abnormal neurogenic inflammatory reactions and that alterations in neuro-immune cells can be remained for longer period in brain than blood.