Effect Of TAM Receptor Gene Knockout On Toll-like Receptor Expression In Hippocampus Of Carbon Monoxide Poisoning Delayed Encephalopathy Mice Model

Objective:To explore the expression of TLR2 and TLR4 in the pathogenesis of DEACMP,and whether TAM gene knockout can affect the expression of TLR receptor under this condition.In order to indicate the effect of TAM receptor on inflammatory response in the pathogenesis of DEACMP.Methods:Breeding of wild mice,Axl gene knock-out mice(Axl^-/-)and Mer gene knock-out mice(Mer^-/-)mice,the mouse genotype was re-tested before the experiment.The homozygous mice were selected for the experiment.The eligible male mice were randomly divided into DEACMP model group（group D）and air inhalation group（group C）.According to the genotype,they were divided into three groups:wild-type mice with air inhalation group（group CW）,Axl^-/-gene knockout mice with air inhalation group（group CA）,Mer^-/-gene knockout mice with air inhalation group（group CM）,wild-type mice with DEACMP model group（group DW）,Axl^-/-mice with DEACMP model group（group DA）,Mer^-/-mice with DEACMP model group（group DM）.First of all,to explore the air inhalation group,CW,CA,CM between the three groups in the water maze test,whether there are differences in hippocampal tissue pathology.Meanwhile,the transcription and protein expression of TLR2 and TLR4 in mice with different genotypes were detected by quantitative real-time PCR（q PCR）and Western blot（WB）experiment.Then we compare the cognitive function,hippocampal pathology and the differences of TLR2 and TLR4 between DW and CW groups.In addition,the differences of DW,DA and DM groups in the above experiments were also explored to clarify the effects of TAM gene knockout on DEACMP cognition,pathological tissue structure changes and TLR receptor expression.Results:In the air inhalation group,there was no significant difference in the cognitive function and hippocampal tissue changes among the CW,CA and CM groups（P>0.05）,and the lack of TAM receptor had no significant effect on the expression of TLR2 and TLR4（P>0.05）.Compared with the CW group,the Morris water maze test showed that the escape latency of mice in the DW group on the 3rd–5th day was significantly prolonged（P<0.05）,and the overall decline was slowed down.Hippocampal histopathological staining showed disorder and necrosis of pyramidal cells in the hippocampus of mice in DW group.In addition,q PCR and WB experiments also found that the expression of TLR2 and TLR4 receptors in DW group was significantly higher than that in CW group（P<0.05）.By comparing the mice of group of DW,DA and DM,it was found that the escape latency of DA and DM groups was significantly longer than that of wild-type DEACMP model mice in the Morris water maze test（P<0.05）.Hippocampal histopathological results showed that compared with DW group,DA group and DM group had slightly more necrotic cells and slightly disordered hippocampal tissue structure.In addition,it was also found that the m RNA and protein expressions of TLR2 and TLR4 in DA group were significantly higher than those in DW group.Only the expression of TLR4 increased in DM group,but the expression of TLR2 had no significant difference compared with DW group.Conclusions:1.Normally,the absence of Axl and Mer receptors in TAM family has no significant effect on the expression of TLR2 and TLR4.2.The expression of TLR2 and TLR4 receptors increased in the pathogenesis of DEACMP.3.In the pathogenesis of DEACMP,the deletion of Axl receptor will lead to the increase of TLR2 and TLR4 expression,while the deletion of Mer receptor will affect the expression of TLR4 receptor,which may lead to excessive inflammatory response in the pathogenesis of DEACMP and aggravate cognitive dysfunction.