Expression Of Myeloid Cell-triggered Receptor-1 In Early Brain Injury After Experimental Subarachnoid Hemorrhage

Objective:Subarachnoid hemorrhage(SAH)is one of the serious cerebrovascular diseases with high mortality and disability.In recent years,early brain injury(EBI)is the main cause of poor prognosis in SAH.The inflammatory response plays a key role in EBI.Myeloid cell trigger receptor-1(TREM-1)is considered to be a key mediator of inflammatory development and amplification and may be involved in the inflammatory response during EBI.Previous studies have initially found an increase in the concentration of soluble TREM-1(sTREM-1)in cerebrospinal fluid(CFS)in SAH patients,but the expression pattern of TREM-1 is still unclear.Therefore,this study will further detect the expression of TREM-1 in EBI after experimental SAH.To observe the expression of TREM-1 in rat brain tissue at different time points in EBI time window after SAH and to study the correlation between TREM-1 and inflammatory factors and neurological function scores,and explore the role of TREM-1 in EBI formation.Provide new targets for the prevention and treatment of EBI.Methods:The SAH model was prepared by intra-cervical vascular puncture.All models were evaluated for bleeding severity and neurological function scores.Twelve rats were randomly assigned to the sham operation group and the SAH group.The expression of TREM-1 was evaluated by immunohistochemistry 24 hours after modeling;48 rats were randomly assigned to the sham operation group and different time points at6 h,12h,24 h,48h and 72 h,brain tissues were taken and further analyzed by Westernblotting to dynamically change the level of TREM-1 and collect cerebrospinal fluid for later use.Then,at the time point of the peak of TREM-1 level,the severity of TNF-αand IL-1β inflammation in CSF of rats at this time was evaluated by enzyme-linked immunosorbent assay,and finally data integration was performed to analyze the relationship between the expression of TREM-1 and the severity of inflammation And neurological scores.Results:1.Immunohistochemical analysis showed that the number of TREM-1 positive cells was significantly increased at 24 h after SAH in rats compared with the sham operation group(2.67±0.82 vs 0.83±0.41),which was statistically significant(P<0.05).2.The results of Western blot analysis showed that there were dynamic changes in the expression levels of TREM-1 in the EBI time window after SAH in rats,which increased at 6 h after SAH and peaked at 48 h,but at 12 h to 72 h.The expression of TREM-1 protein was significantly higher than that of the sham operation group(P<0.05).3.Correlation analysis showed that the production of TREM-1 was positively correlated with the expression of TNF-α(r =0.726,P = 0.041 <0.05)and IL-1β(r =0.711,P =0.048 <0.05),and was negatively correlated with neurological function score(r =-0.743,P = 0.035 <0.05).Conclusions:TREM-1 production in the EBI after experimental SAH is dynamically increased in the brain and peaks at 48 hours,correlating with severity of inflammation and neurological function scores,suggesting that TREM-1 may be involved in the pathogenesis of EBI inflammation after SAH.