Chang Of NMDAR1, NMDAR1mRNA HSP70 Expression In Neonatal Rat Brain Following Cerebral Hypoxia-ischemia And The Protective Effect Of GM1

Objective To study the expression of NMDAR1 NMDARlmRNA and HSP70 and pathologic damage in hippocampal CA1, and the effect of monosialotctrahexosylganglioside (GM1) on the expression and pathologic changes after hypoxic-ischemic brain damage (HIBD) in neonatal rats. Methods: An animal model of neonatal hypoxic-ischemic brain damage was developed by ligating the left unilateral carotid artery of 7-day-old rats and keeping the rats in a hypoxic(80ml . L-1oxygen)environment for 2 hours.â‘ Model of HIBD group(untreated group).â‘¡Model of GM1 treated group. Everyday GM1 were injected through abdominal cavity(intraperitoneal administration with GM1)after HIBD in neonatal rats.The rat brain tissues were collected at different time following hypoxia-ischemia. Hematoxylin-eosin (HE) staining, Envision immunohistochemistry and NR1mRNA in situs hybridization were used to detect the pathologic changs,the expression of NR1 protein,HSP70 protein and NRlmRNA gene in the hippocampus,respectively.Results: the expression of NR1, HSP70 and NRlmRNA, and the pathologic damage in HIBD group have changed significantly ,compared with control group. @1 NR1 positive cells and NRlmRNA positive cells were decreased in hippocampal CA1 area in 2h after HI.The increase began from 24h to 48h afterHI,peaked at 72h after HI.â‘¡ The expression of HSP70 could hardly be was observed in hippocampal CA1 after HI in neonatal rats.â‘¢ the neuron showed severe ischemic damage in hippocampal CA1 area began at 24 hours and peaked at 72 hours after HI.2.There were some changes significantly in GM1 treated group,compared with H1BD group(untreated group).â‘  NR1 positive cells and NRlmRNA positive cells were decreased in hippocampal CA1 area after GM1 administration in GM1 group compared to that of HI group.â‘¡ The expresion of HSP70 began at 2 hours,peaked at 24 hours,decreased at 48 hours,and was still distinct than that of control group in GM1 group.â‘¢ The changes of pathology had more remarkable improvement after GM1 group compared to that of HI group. Conclusion: These results indicate that1. There exsits expression of NR1 and NRlmRNA in nomal neonatal rats,and the expression of NR1 and NRlmRNA is up-requlationed after HI.2. Hsp70 expression can hardly be observed under seriouse hypoxia-sichemia however the HSP70 expressio improved under light injury such as sham operation.lt indicate that HSP70 related to repair of damage.3. The expression of NR1 and NRlmRNA is down-regulationed,the expression of MSP70 improve,HIBD pathologic injury reduce after GM1 administration in GM1 group compared to that of HI group.GMl has the effect of brain protect against hypoxia-ischemia.