n-3多不饱和脂肪酸对坏死性小肠结肠炎保护作用的机制研究

The mechanism and protective effect of n-3 polyunsaturated fatty acids on necrotizing enterocolitis

目的探讨n-3多不饱和脂肪酸对坏死性小肠结肠炎(NEC)保护作用的机制。方法将30只3日龄的C57BL/6J乳鼠随机分成DF组、NEC组及n-3补充组(n=10)。观察每组小鼠NEC发生情况与严重程度;组织学检测乳鼠肠道组织损伤情况;采用ELISA检测乳鼠肠组织IL-1β和TNF-α的分泌水平;利用qRT-PCR与Western Blotting方法检测ZO-1、claudin-4和claudin-7基因及蛋白的表达;采用CaCo2细胞株构建肠上皮细胞炎症模型,检测DHA对紧密连接蛋白表达水平的影响。结果与DF组相比,NEC组体重显著降低,而饲喂n-3多不饱和脂肪酸可显著缓解体重下降。与DF组相比,NEC组肠组织损伤严重,而n-3补充组较NEC组损伤程度显著减轻。与DF组相比,NEC组炎症因子水平显著上升,而n-3补充组较NEC组炎症因子水平下降显著。与DF组相比,NEC组乳鼠肠组织中ZO-1、claudin-4和claudin-7蛋白表达水平显著下降,而n-3多不饱和脂肪酸能促进紧密连接相关蛋白的表达。在CaCo2细胞炎症模型中,DHA能促进ZO-1、claudin-4和claudin-7蛋白的表达,并能维持紧密连接蛋白的正确分布。结论n-3多不饱和脂肪酸通过维持肠上皮细胞紧密连接减轻坏死性小肠结肠炎的发生发展。

Objective To explore the mechanism and protective effect of n-3 polyunsaturated fatty acids on necrotizing enterocolitis.Methods 303-day-old C57BL/6J mice were randomly divided into three groups(n=10):DF group,NEC group and n-3 supplementary group.Observing the occurrence and severity of NEC in each group;intestinal injury of neonatal mice was detected by histological methods;the levels of IL-1βand TNF-αin the intestinal tissues were detected by ELISA;the expression of tight junction-related genes and proteins were detected by qRT-PCR and western blotting methods;using CaCo2 cell line to establish the intestinal epithelial cell inflammation model,the effect of DHA on the expression of tight junction proteins were detected.Results Compared with DF group,weight loss was significantly increased in NEC group,and weight loss was significantly alleviated by feeding n-3 polyunsaturated fatty acids.Compared with DF group,intestinal tissue injury in NEC group was more serious,while the injury degree in n-3 supplementation group was significantly reduced compared with NEC group.Compared with the DF group,the levels of inflammatory cytokines were significantly increased in the NEC group,while significantly decreased in the n-3 supplementation group compared with the NEC group.Compared with DF group,the expression levels of ZO-1,Claudin-4 and Claudin-7 in the intestinal tissues of neonatal mice in NEC group were significantly decreased,while n-3 polyunsaturated fatty acids could promote the expression of tight junction-related proteins.Conclusion n-3 polyunsaturated fatty acids can alleviate the development of necrotizing enterocolitis by maintaining tight junction of intestinal epithelial cells.