Wang Zhongtang, Xiao Guangxia, Yao Yongming, Guo Shuzhong, Lu Kaihua, Sheng Zhiyong
Center of Plastic Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
J Trauma. 2006 Sep;61(3):650-7. doi: 10.1097/01.ta.0000196574.70614.27.
Early multiple organ dysfunction syndrome appears to be facilitated with bacterial translocation in severe burn injury, yet the mechanisms of bacterial translocation remain in dispute. The aim of this study was to characterize the potential role of intestinal bifidobacteria in the pathogenesis of gut-derived bacterial translocation after burns and to analyze the effects of bifidobacterial supplement on gut barrier function.
Wistar rats were randomly divided into burn group (Burn, n = 60), sham burn group (SB, n = 10) in experiment 1, and burn + saline group (BS, n = 30), burn + bifidobacteria group (BB, n = 30), and sham-burn + saline group (SS, n = 30) in experiment 2. Animals in BB group were fed bifidobacterial preparation (5 x 10(9) CFU/mL) after burns, 1.5 mL, twice daily. Animals in BS and SS were fed saline. Samples were taken on postburn days 1, 3, and 5. The incidence of bacterial translocation and counts of Bifidobacterium, fungi and Escherichia coli in gut mucosa, as well as the sIgA levels in mucus of the small intestine were determined. The positive sIgA expression in lamina propria and ileum mucosal injury were evaluated light microscopically by blinded examiners.
The incidence of bacterial translocation was increased after burns, which was accompanied by significant decrease in number of bifidobacteria but significant increase in E. coli and fungi in gut mucosa, and elevation of levels of plasma endotoxin and IL-6 (p < 0.001). The incidence of bacterial translocation was markedly reduced after 3- and 5-day supplementation of bifidobacteria compared with control group (p < 0.05). The counts of mucosal bifidobacteria were increased by 4- to 40-fold, whereas E. coli and fungi were decreased by 2- to 30-fold and 10- to 150-fold, respectively, after bifidobacterial supplementation. The damage of mucosa tended to be less pronounced after 3-day bifidobacteria-supplemented formula compared with control group (grade 2 [0-6] versus grade 4 [3-6], p < 0.05). Moreover, the expression and release of sIgA was markedly augmented after 3-days of bifidobacteria-supplementation formula and it returned to normal range on postburn day 5.
The decrease in counts and proportion of bifidobacteria to other flora in gut may play an important role in the development of bacterial translocation after thermal injury. Supplementation of exogenous bifidobacteria could improve gut barrier function, and attenuate bacterial/endotoxin translocation secondary to major burns.
严重烧伤时，早期多器官功能障碍综合征似乎因细菌移位而加重，然而细菌移位的机制仍存在争议。本研究旨在探讨肠道双歧杆菌在烧伤后肠道源性细菌移位发病机制中的潜在作用，并分析补充双歧杆菌对肠道屏障功能的影响。
在实验1中，将Wistar大鼠随机分为烧伤组（Burn，n = 60）、假烧伤组（SB，n = 10）；在实验2中，分为烧伤+生理盐水组（BS，n = 30）、烧伤+双歧杆菌组（BB，n = 30）、假烧伤+生理盐水组（SS，n = 30）。BB组动物在烧伤后给予双歧杆菌制剂（5×10⁹CFU/mL），1.5 mL，每日2次。BS组和SS组动物给予生理盐水。在烧伤后第1、3和5天采集样本。测定细菌移位的发生率、肠道黏膜中双歧杆菌、真菌和大肠杆菌的数量，以及小肠黏液中sIgA水平。由盲法检查人员通过光学显微镜评估固有层中sIgA的阳性表达和回肠黏膜损伤情况。
烧伤后细菌移位发生率增加，同时肠道黏膜中双歧杆菌数量显著减少，而大肠杆菌和真菌数量显著增加，血浆内毒素和IL-6水平升高（p < 0.001）。与对照组相比，补充双歧杆菌3天和5天后，细菌移位发生率显著降低（p < 0.05）。补充双歧杆菌后，黏膜双歧杆菌数量增加4至40倍，而大肠杆菌和真菌数量分别减少2至30倍和10至150倍。与对照组相比，补充双歧杆菌3天后，黏膜损伤趋于减轻（2级[0 - 6]对4级[3 - 6]，p < 0.05）。此外，补充双歧杆菌3天后，sIgA的表达和释放显著增加，并在烧伤后第5天恢复至正常范围。
肠道中双歧杆菌数量及其占其他菌群比例的减少可能在热损伤后细菌移位的发生中起重要作用。补充外源性双歧杆菌可改善肠道屏障功能，减轻严重烧伤继发的细菌/内毒素移位。
