Effects Of Sympathetic Excitability On Peripheral Blood CD4~+CD25~+Treg Level And Lung Injury In Rats With Traumatic Brain Injury

Objective:By analyzing the level of epinephrine,the changes of CD4~+CD25~+Treg and the pathological changes of lung tissue in the early stage after traumatic brain injury in rats.This paper discusses whether sympathetic excitability triggers the immunosuppression of trauma and then causes lung injury after traumatic brain injury.Methods:Ninty-six male Sprague Dawley rats(250±50g)were randomly separated into the group of A to H.Group A is the normal control group.Group B(traumatic brain injury group):according to the sample collection time,they were divided into 2 hours,4 hours and 6hours according to the sample collection time.Group C was a false surgical group.Group D(traumatic brain injury group for 2h)is namely group B for 2h.Group E was the cervical sympathectomy group.Group F(traumatic brain injury+normal saline group):group F was divided into3 hours,6 hours and 9 hours according to the sample collection time.Group G(traumatic brain injury+esmolol group):group G was divided into 3 hours,6 hours and 9 hours according to specimen collection time;Group H(sham operation+normal saline group):according to the sample collection time,it was divided into 3 hours,6 hours and 9 hours according to specimen collection time.Serum epinephrine concentration and CD4~+CD25~+Treg ratio in peripheral blood were measured.The pathological changes of lung tissue and pathological score of lung injury were observed.Results:1.Changes of epinephrine concentration and CD4~+CD25~+Treg ratio in peripheral blood of rats:In contrast to group A,peripheral blood epinephrine concentration and CD4~+CD25~+Treg ratio in group B were significantly increased at each time point(P<0.01),and with the change of time,serum adrenaline concentration and peripheral blood CD4~+CD25~+Treg ratio were all increased in group B at 2h,B at 4h and B at 6h.The differences were statistically significant at at 2h,4h and 6h time points(P<0.01).Correlation analysis of serum adrenaline concentration and peripheral blood CD4~+CD25~+Treg ratio showed a linear correlation(0<R<1,P<0.01).In contrast to group C,the ratio of CD4~+CD25~+Treg in peripheral blood of rats in groups D and E was greatly increased(P<0.01).In contrast to group D,the ratio of CD4~+CD25~+Treg in group E was lower(P<0.05).The ratio of CD4~+CD25~+Treg had no significant change in group H(P>0.05).The ratio of CD4~+CD25~+Treg in group F was greatly increased at each time point(P<0.01),and the ratio of CD4~+CD25~+Treg in group F was significantly higher than that in group H and group G at the same time point(P<0.05).The ratio of CD4~+CD25~+Treg in group G was increased at each time point(P<0.05).The ratio of CD4~+CD25~+Treg at the same time point was lower than that in F group,but still higher than that in H group.The difference was meaningful in statistics(P<0.05).2.Variation of pathological and pathological score of lung tissue (IQA):In contrast to the group A,lung injury IQA in group B was significantly increased at each time point(P<0.01),and lung injury was aggravated over time,The difference was meaningful in statistics at 2h,4h and 6h(P<0.01).Compared with group C,IQA of lung injury in group D was significantly increased(P<0.01),and IQA of lung injury in group Ewas significantly increased(P<0.05).Compared with group D,lung tissue lesions in group E were reduced,and alveolar tissue structure was complete in the main,but lung interstitium thickening and inflammatory cells increased,and lung injury decreased of IQA(P<0.01).Lung injury IQA in group H had no significant change at each time point(P>0.05).Lung injury IQA in group F was significantly increased at each time point(P<0.01),and lung injury IQA in group G was significantly increased at each time point(P<0.05).Compared with group H,lung injury IQA in groups F and G increased at the same time point(P<0.05).Compared with F group,lung injury IQA in G group was decreased at the same time point.The difference was meaningful in statistics(P<0.05).Conclusions:1.In the early stage of traumatic brain injury,rats have high sympathetic excitation and raise the level of CD4~+CD25~+Treg,causing lung injury.2.Early blocking or reducing sympathetic nerve excitability can reduce the level of CD4~+CD25~+Treg and reduce lung injury.