Objective To investigate the expression of Monocyte Chemoattractant Protein-1 (MCP-1) in the brain of neonatal rats subjected to hypoxia ischemia and the influence of different doses of dexamethasone on the expression of MCP-1 protein and neuropathology. Methods Using a hypoxic ischemic neonatal rat model (n=25), animals received intraperitoneal injections of normal saline (control group), and 0.5 mg/kg and 10 mg/kg of dexamethasone immediately after the hypoxic injury. All animals were killed 24 hours after hypoxia. Immunocytochemistry with a polyclonal goat antirat MCP 1 antibody was used to determine the expression of MPC 1 protein. Total and percentage denatured (necrotic) neurons were determined using light microscopy. Results In the control group, the expression of MCP 1 protein and the total number of neurocytes and denatured (necrotic) neurons were 7.98 ± 1.37% , 158.07 ± 14.48 /6HP and 22.86 ± 3.13 /6HP, respectively, while in the high dose group, they were 0.97 ± 0.42% , 203.25 ± 10.27 /6HP and 17.75 ± 3.45 /6HP, respectively. And in the low dose group, they were 7.25± 2.45% , 155.11 ± 16.61 /6HP and 23.89 ± 4.18 /6HP, respectively. Compared to the control group, the expression of MCP 1 protein was significantly decreased (P< 0.01 ),the total number of neurons increased (P< 0.05 ), and denatured (necrotic) neurons decreased (P<0.01) in the high dose groups, but there were no major histopathological differences between the low dose group and the control group. Conclusions High dose dexamethasone treatment reduces the expression of MCP-1 protein in the brain of neonatal rats with hypoxic ischemic encephalopathy, and might have a neuroprotective role in this disorder. [