Repetitive administration of acetylcholine receptor agonist rescues brain inflammation and brain damage after hypoxia-ischemia in newborn rat.

OBJECTIVE: We examined the effect of repetitive administration of acetylcholine receptor agonist (carbachol) on brain damage and microglial accumulation in three brain regions after hypoxia-ischemia (HI) in newborn rat. STUDY DESIGN: Seven-day-old Wistar rats were divided into two groups, one receiving a 0.1 mg/kg dose of carbachol on days 7, 8 and 9 to examine the attenuating effect on brain damage with decreasing accumulation of microglia, and the other group receiving saline as a control. Rats were subjected to left carotid artery ligation followed by hypoxia. We evaluated brain damage and the number of microglias in three regions on days 10 and 14. RESULTS: Brain tissue was better preserved in the carbachol group on days 10 and 14. Microglial accumulation in the cortex was strong and persisted from day 10s to 14 in the control. Conversely, the accumulation of microglias was attenuated in the hippocampus and white matter on day 14. Carbachol significantly reduced the number of microglias in the hippocampus and white matter on day 10 and in the cortex on days 10 and 14. CONCLUSION: The main area of late inflammation was the cortex. Repetitive administration of carbachol reduces early and late inflammation after HI in the developing brain.