The Change Of Regulatory T Cells In Intestinal Lymph Node And Its Relation With Gut-original Endotoxin/Bacteria] Translocation In Severely Burned Rats

Objective: To observe the change of regulatory T cells expression in severely burnedrats gut, To investigate the effects of regulatory T cells on CD3+CD4~+/CD3+CD8~+lymphocytes and its relation with gut-origin endotoxin/bacterial translocation.Methods: Fifty SD male rats were randomly divided into normal control group(n=10)and burn model groups(n=40).Rats were burned with vapor under3mPapressure and107℃temperature for thirteen seconds to achieve III degreescalding,and a30%total body surface area(TBSA) burn model was made. Rats weresacrificed before(normal control group) and after12,24,36,48burn hour (PBHgroups).Flow cytometry techniques were used for the detection of the expressions ofregulatory T cells and CD3+CD4~+/CD3+CD8~+lymphocyte in intestinal lymphnodes which were separated. The dynamic turbidity method was used for detection ofendotoxin levels in portal vein blood and organs bacterial translocation rate were alsodetected.Results:(1) The percentage of regulatory T cells in12post burn hour(12PBH),24PBH,36PBH, and48PBH groups rats were17.42±1.17,25.65±1.43,36.83±0.68,40.66±0.93, and that in normal control group is8.07±0.82, There was a significantdifference between control group and PBH groups(P<0．01)．(2) CD3+CD4~+/CD3+CD8~+lymphocyte ratio were significantly reduced inPBH groups rats compared to normal control group (P <0.01).(3) The level of endotoxin in portal vein blood of12PBH,24PBH,36PBH, and48PBH group rats were2.21±0.15,5.36±0.15,8.04±0.13,10.89±0.14,which wassignificantly elevated compared with that of normal control group (P <0.01).(4) Compared with the normal control group, various organ bacterialtranslocation rate was significantly increased in burn model groups (P <0.01).(5) The expression of regulatory T cells was negatively correlated withCD3+CD4~+/CD3+CD8~+lymphocyte ratio(r=-0.827, P <0.01) in intestinal lymphnode of rats, while the regulatory T cells was positively correlated with ET levels in portal vein blood plasma and various organs bacterial translocation rate(r=0.782and0.803, P <0.01).Conclusion: The expression of the regulatory T cells in intestinal lymph node inseverely burned rats was increased compared to that in normal control group.Regulatory T cells suppressed the expression of intestinal T lymphocytes, leading togut immune inhibition. The translocation of intestinal bacterial and endotoxin have aclose relationship with regulatory T cells in severely burned rats. Regulatory T cellsmay have portal effect on intestinal immunity barrier.