肠道双歧杆菌与烫伤大鼠肠源性细菌/内毒素移位

目的　观察肠道双歧杆菌在肠源性细菌 /内毒素移位中的变化和作用。　方法　制作严重烫伤大鼠模型 ,同时设假伤组。检测细菌和内毒素 (LPS)移位及盲肠膜菌群变化 ,ELISA法检测血浆白细胞介素 6(IL 6)浓度。　结果　大鼠严重烫伤后脏器细菌移位明显增多 (P <0 .0 1) ;血LPS水平在致伤 1、3、5d后分别为 (0 .2 3 6± 0 148)Eu/ml、(0 .197± 0 .15 6)Eu/ml、(0 10 4± 0 .0 90 )Eu/ml,显著高于假伤组的 (0 .0 72± 0 .0 49)Eu/ml(P <0 .0 5 ) ;盲肠膜菌群中双歧杆菌数剧减 2 0～2 5 0倍、真菌数剧增至 5～ 60倍、大肠杆菌数增加 0 .5～ 3 0倍 ,双歧杆菌与大肠杆菌比值由假伤组的2 5 0 0 0∶1降为伤后的 4～ 80 0∶1;血浆IL 6水平显著增高。经分层统计 ,与未发生肠道细菌移位大鼠相比 ,盲肠膜菌群移位大鼠的双歧杆菌量减少约 12 0倍 ,真菌数增加约 5 0倍 ,大肠杆菌数增加约 3 0倍。盲肠膜菌群中双歧杆菌数量与血浆中IL 6、LPS浓度呈负相关 (r1=- 0 .4817,r2 =- 0 .4912 ,P <0 .0 1) ,血IL 6和LPS浓度间存在显著正相关 (r =0 .82 5 8,P =0 .0 0 0 1)。　结论　严重烫伤可导致大鼠盲肠膜菌群紊乱 ,细菌和LPS移位增加 ;盲肠膜菌群中双歧杆菌的比例和数量的减少 ,可能促使了严重烫伤后肠源性细菌 /内毒素移位

The relationship between intestinal bifidobacteria and bacteria/endotoxin translocation in scalded rats

OBJECTIVE: To investigate the potential role of intestinal bifidobacteria in the pathogenesis of gut-origin bacteria/endotoxin translocation in scalded rats. METHODS: Wistar rats inflicted with 30% III degree scalding on the back were employed as the model with the rats undergoing sham injury as the control. The intestinal bacteria/endotoxin translocation and the changes in cecal mucosal microflora were determined by routine methods. And the plasma IL-6 concentration was measured with ELISA. RESULTS: The incident of bacterial translocation into internal organs increased markedly in scalded rats (P = 0.001). The plasma LPS levels on 1, 3 and 5 postburn days (PBDs) in scalded rat group were much higher than those in sham injury group. The number of bifidobacteria decreased sharply 20 - 250 fold, the fungi increased 5 - 60 fold and E. coli increased 0.5 - 30 fold in the caecal mucosal microflora in the scalding group. The ratio of bifidobacteria to E. coli in the scalding group (4 - 800:1) was much lower than that in the sham injury group (25000:1). Furthermore, the plasma IL-6 level increased evidently in the scalding group. It was indicated by further analysis that compared with the rats without bacterial translocation, the bifidobacteria decreased 120 fold, the fungal number increased 50 fold and the E. coli number increased 30 fold in the scalded rats. The bifidobacterial number in the caecal mucosal microflora was negatively correlated with the plasma concentrations of IL-6 and LPS (P < 0.01) in the scalding rat group, and the plasma concentration of IL-6 was significantly and positively correlated with that of LPS. CONCLUSION: Severe scalding injury could lead to an the imbalance of intestinal microflora and the increased intestinal translocation of bacteria and LPS. The decrease of the ratio and number of bifidobacteria in the caecal mucosal microflora might be a contribute to the occurrence of postburn intestinal bacteria/endotoxin translocation.