Protective effects of fenofibrate against acute lung injury induced by intestinal ischemia/reperfusion in mice

Zhu, Qiankun; He, Guizhen; Wang, Jie; Wang, Yukang; Chen, Wei

Histological examination. Morphological changes in the intestine and lungs were examined by hematoxylin and eosin (HE) staining. Every lung lobe was divided equally for histopathological and biochemical investigations. Briefly, portions of left lung (the upper left lobe and lower left lobe) and the right lung (the anterior lobe, the posterior lobe, the median lobe and the post caval lobe) were separately immersed in 10% buffered formalin phosphate, dehydrated in alcohol, embedded in paraffin, and then cut into 4-um sections through the middle of the lobe so that every section included hilum to periphery. The extents of histological injury were evaluated by two blinded experienced investigators. The lung injury was evaluated to the level of absent, mild, moderate, or severe injury (score 0-3) by observing the presence of exudates, hyperemia/congestion, neutrophil infiltration, intra-alveolar hemorrhage/debris and cellular hyperplasia 16 . Ten areas of the lung tissue section for each lung lobe were randomly selected within microscopic high power fields. The lung injury score assessed in each category for every individual mouse was the mean of the scores from the sections of the lungs examined, and total lung injury score was calculated by adding the scores in each of these categories. The intestinal injury was scored on a scale from 0 to 5 as described by Chiu et al 17 . Grade 0-Normal mucosal villi. Grade 1-Development of edema in sub-epithelial space, usually at the apex of the villus; often with capillary congestion. Grade 2-Extension of the subepithelial space with moderate lifting of epithelial layer from the lamina propria. Grade 3-Massive epithelial lifting down the sides of villi and a few tips may be denuded. Grade 4-Denuded villi with lamina propria and dilated capillaries exposed and increased cellularity of lamina propria may be noted. Grade 5-Digestion and disintegration of lamina propria and presence of hemorrhage and ulceration. The intestine injury grade in the Chiu scoring system from five sections was averaged to represent the grade for each animal.