Effects Of Intermittent Hypoxia And Reoxygenation On Intestinal Mucosal Barrier Function In Mice

Objective:Based on the mouse model of intermittent hypoxia(IH)combined with high-fat diet,this study investigated the effects of IH and high-fat diet on intestinal mucosal injury,intestinal barrier function and intestinal epithelial cell apoptosis in mice.The effects of continuos positive airway pressure(CPAP)in patients with obstructive sleep apnea hypopnea syndrome(OSAHS)were simulated by comparing before and after reoxygenation.Methods:To construct a mouse model of IH combined with high-fat diet,the 6-week-old C57BL/6J male mice were randomly divided into four groups,12 in each group.The mice in each group were given common diet(CD)or high fat diet(HFD).During this period,different treatments were given to the mice in the four groups:(1)Common diet +normal oxygen group(CD group);(2)High fat diet + normal oxygen group(HFD group);(3)Common diet + intermittent hypoxia group(CD+IH group);(4)High fat diet +intermittent hypoxia group(HFD+IH group).After 6 weeks of experiment,intestinal mucosa samples of mice in each group were studied.Methods:(1)The morphological changes of colonic mucosa were observed by HE staining.(2)Immunohistochemical staining was used to observe the distribution of colonic ZO-1 and Occludin in tissues.(3)Identification of mucin layer in mouse colon by immunofluorescence.(4)The apoptosis of intestinal epithelial cells was observed by TUNEL staining.The original diet of mice remained unchanged,and the intermittent hypoxia group was reoxygenated for 2 weeks.The above HE staining and immunohistochemical detection of ZO-1 and Occludin were repeated again,and analyzed.Results:Results after IH for 6 weeks:1.HE showed that the epithelial structure of colon mucosa in the CD group was intact.The damage of colon mucosa can be observed in HFD,CD+IH and HFD+IH group,and HFD+IH group was the most.2.Immunohistochemistry showed that,compared with the CD group,the expression levels of ZO-1 in HFD,CD+IH and HFD+IH group were decreased(P < 0.01),and the expression levels in CD+IH and HFD+IH group were decreased significantly;Compared with the CD group,the expression level of Occludin in HFD group was slightly lower,and the difference was not statistically significant,while the expression levels of Occludin in CD+IH and HFD+IH group were decreased(P < 0.05),and the differences were statistically significant.3.Immunofluorescence showed that,compared with the CD group,the mucin-layer Muc-2 expression in the colon of HFD,CD+IH and HFD+IH groups was decreased,and the decrease of Muc-2 expression was more significant in the CD+IH and HFD+IH groups.4.TUNEL showed that compared with the CD group,the apoptosis rate of intestinal epithelial cells in HFD group was slightly higher,and the difference was not statistically significant,while the apoptosis rate of intestinal epithelial cells in CD+IH and HFD+IH groups was significantly increased(P < 0.05).Results after 2 weeks of reoxygenation:1.HE showed that the damage of colon mucosa in CD+IH and HFD+IH groups was less than that before reoxygenation.2.Immunohistochemistry showed that,compared with before reoxygenation,the expression of colon ZO-1 in CD+IH and HFD+IH groups was greatly increased(P <0.01);Compared with before reoxygenation,the expression of Occludin in CD+IH group was slightly higher,and the difference was not statistically significant,while the expression of Occludin in HFD+IH group was increased,and the differences was statistically significant(P < 0.01).Conclusion:1.Both intermittent hypoxia and high-fat diet can damage the integrity of intestinal mucosal layer,and this damage is more significant in the presence of both.2.Both intermittent hypoxia and high-fat diet can cause decreased expression of ZO-1 and Occludin,and decreased secretion of Muc-2 in colon tissue of mice,and this damage is more significant in the presence of both,and the apoptosis of intestinal epithelial cells is significantly increased.3.Short-term reoxygenation can slightly improve the pathological injury of colon tissue,and make the expression of ZO-1 and Occludin in colon tissue recover.