生命早期母体高脂饮食诱导子代小鼠肠道低度炎症对肠黏膜屏障的影响

Effect of maternal high fat diet on intestinal barrier function in early life of offspring mice

目的探讨生命早期(孕期及哺乳期)母体高脂饮食(MHFD)对子代小鼠肠黏膜屏障的影响。方法C57BL/6妊娠小鼠随机分为MHFD组和正常饮食(MND)组,正常分娩后监测子代小鼠体质量,并评价3周龄的肠道通透性;免疫荧光法评价肠道组织紧密连接蛋白(ZO-1)的表达;HE染色评价小肠绒毛和结肠隐窝发育及炎症情况;免疫组织化学法评价肠道细胞增殖(Ki-67)及黏蛋白(MUC2)的表达;PAS染色法评价杯状细胞的数目;实时荧光定量PCR检测肠道组织中炎症因子mRNA的相对表达量。结果MHFD组子代小鼠2周及3周时体重高于MND组。3周时两组肠道均未发现显著镜下炎症,而MHFD组子代小鼠促炎因子白介素(IL-1β)[(1.95±0.53比1.13±0.15,t=3.65,P=0.005)、IL-6(1.40±0.71比0.73±0.17,t=2.72,P=0.04)和TNF-α(1.63±0.53比1.04±0.12,t=2.64,P=0.02)mRNA相对表达水平较MND组上升;MHFD组子代小鼠肠道通透性增加,肠道ZO-1膜定位表达明显减低;小肠绒毛长度及结肠隐窝深度明显缩短;每个小肠绒毛中Ki-67阳性细胞数[(18.00±4.74)个比(24.60±4.17)个,t=3.31,P=0.004]明显减少;每个结肠隐窝中杯状细胞的数目[(14.70±2.91)个比(28.10±4.95)个,t=7.38,P<0.001]和MUC2阳性细胞数[(20.60±3.13)个比(30.00±3.33)个,t=6.50,P<0.001]均明显减少。结论生命早期母体高脂饮食可诱导子代小鼠肠道低度炎症,破坏肠黏膜屏障,可能参与子代疾病发生。

Objective To observe the effects of maternal high fat diet (MHFD) during pregnancy and lactation on intestinal barrier function in offspring mice. Methods C57BL/6 pregnant mice were divided into high fat diet (MHFD) group and normal diet group (MND) randomly and were given high fat diet and normal diet during pregnancy (3 weeks) and lactation (3 weeks) respectively. Both groups of offspring mice were naturally given and bodyweight of pups was monitored at birth and weekly. After weaning, the intestinal permeability of offspring mice was detected by fluorescein isothiocyanate conjugated-dextran method (FITC-D). Immunofluorescence was used to detect the expression of ZO-1 in intestinal tissues. HE staining was used to assess the villus length and crypt depth. The intestinal cell proliferation(expression of Ki-67)and Mucin 2(MUC2) were assessed by immunohistochemistry. PAS staining was used to evaluate the goblet cells. The expression of inflammatory cytokines including IL-1β, IL-6, and TNF-α in intestinal tissue were measured by real-time PCR. Results At the age of 2 and 3 weeks, the offspring in MHFD group were significantly heavier than those in MND group. HE staining showed no obvious microscopic inflammation in both groups of 3 weeks old offspring mice, however, the relative expression levels of IL-1β(1.95±0.53 vs. 1.13±0.15;t=3.65, P=0.005), IL-6(1.40±0.71 vs. 0.73±0.17;t=2.72, P=0.04), and TNF-α(1.63±0.53 vs. 1.04±0.12;t=2.64, P=0.02) mRNA were significantly higher in the MHFD group. Compared with the 3 weeks old offspring mice in MND group, MHFD significantly increased the permeability of intestine and decreased the expression of ZO-1 in membrane. The number of Ki-67 positive cells (18.00±4.74 vs. 24.60±4.17;t=3.31, P=0.004) in each villus, goblet cells (14.70±2.91 vs. 28.10±4.95;t=7.38, P<0.001) and MUC2 positive cells (20.60±3.13 vs. 30.00±3.33;t=6.50, P<0.001) in each crypt were significantly lower than those in MND group. Conclusion Maternal high fat diet in early life of offspring mice can induce intestinal low grade inflammation and lead to the disruption of intestinal mucosal barrier in offspring mice, which may be involved in the progeny diseases.