A study on alleviation of acute lung injury in rats with bowel repletion pattern by mesenteric lymph drainage and its mechanism / 中国中西医结合急救杂志

ABSTRACT

Objective To observe the effects of mesenteric lymph drainage on acute lung injury and expression of p38 mitogen activated protein kinase (p38MAPK) signal pathway in rats with bowel repletion pattern. Methods Thirty male Wistar rats were randomly divided into three groups according to random number table method, namely sham operation group (sham group), bowel repletion model group (model group) and mesenteric lymph drainage group (drainage group), 10 rats in each group. The rat model of bowel repletion was established by ischemia/reperfusion (I/R) method, firstly 1 hour occlusion of superior mesenteric artery (SMA) to induce ischemia followed by reperfusion for 2 hours. In the rats of drainage group, the drainage of mesenteric lymph duct began at the end of model establishment and persisted for 3 hours. In the rats of sham group, the SMA and mesenteric lymph ducts were exposed with blunt dissection, and then they were immediately placed back into the abdominal cavity. After 3 hours of mesenteric lymph drainage, the lung and ileum tissues of rats in each group were harvested for evaluation of pathohistological changes and for the determination and comparison of myeloperoxidase (MPO) activity changes; the levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in bronchoalveolar lavage fluid (BALF) were detected by enzyme linked immunosorbent assay (ELISA), and the expressions of Toll-like receptor 4 (TLR4) mRNA and p38MAPK mRNA in the lung tissues were measured by fluorescence quantitative polymerase chain reaction (PCR).Results Under the light microscope, the pulmonary capillaries markedly dilated and congested, the interstitium width of lung increased with a large amount of inflammatory cells infiltration, the intestinal mucosal layer becoming thinner with detachment of intestinal villi and a large amount of inflammatory cells infiltration were detected in rats of model group. Compared with those in sham group, the levels of TNF-α and IL-6 in BALF, the MPO activity of lung and ileum tissues, and the expressions of TLR4 mRNA and p38MAPK mRNA in the lung tissues were significantly increased in model group.Compared with those in model group, the pathohistological damages in lung and ileum tissues were ameliorated, the levels of TNF-α and IL-6 in BALF, the MPO activity of lung and intestinal tissues and the expressions of TLR4 mRNA and p38MAPK mRNA in the lung tissues were lower in the rats of drainage group [TNF-α in BALF (ng/L): 858.55±27.16 vs. 1 680.58±105.62; IL-6 in BALF (ng/L): 0 vs. 484.71±5.43; MPO activity of lung (U/g): 0.95±0.13 vs. 1.36±0.11; MPO activity of ileum tissues (U/g): 0.75±0.13 vs. 1.30±0.16; TLR4 mRNA: 0.21±0.11 vs. 0.69±0.13, p38MAPK mRNA: 0.21±0.13 vs. 0.47±0.09; allP < 0.05].Conclusion Mesenteric lymph drainage can alleviate acute lung injury in rats with bowel repletion, and its mechanism may be related to the reduction of the expressions of TLR4 mRNA and p38MAPK mRNA and the release of TNF-α and IL-6 in lung tissues.