Study Of Maternal High-Fat Diet Exacerbates Colitis Of Offspring Mice In Adulthood

AimIt has been demonstrated that early life(the period of maternal gestation and lactation)plays a pivotal role in the development of offspring.Both epidemiological and experimental data suggested that maternal high fat diet in early life could lead to the alterations of metabolic level,inflammation,and microbiota.Moreover,these changes can be transmitted to the offspring and increase the susceptibility of offspring to many diseases,such as obesity and diabetes.Although a recent study has reported maternal high fat diet consumption in early life can enhance the susceptibility of offspring to IBD,the underlying mechanism was not defined.Thus,we established an animal model of maternal high fat diet.The intestinal development,mucosal barrier,inflammatory state and microbiome of offspring were assessed.The aim of this study is to observe the effects of maternal high fat diet in early life on the susceptibility of offspring mice to DSS-induced colitis in adulthood and the possible mechanism.Material and MethodsC57BL/6 pregnant mice were randomly assigned to maternal high fat diet(MHFD)group and maternal normal diet(MND)group.After then,MHFD group dams consumed high fat diet whereas MND group dams consumed normal diet during gestation(21 days)and lactation(21 days)respectively.Afterwards,dams delivered vaginally and the bodyweight of pups was monitored at birth and weekly until 8 weeks.The feces of 3-week old offspring were collected and the microbial analysis was performed by 16 S r DNA gene sequencing.After weaning,the intestinal permeability of offspring mice was detected by fluorescein isothiocyanate conjugated-dextran(FITC-D)method.H&E staining was used to assess the villus length,crypt depth,and inflammatory state.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 membrane localization of ZO-1 in colon was detected by immunostaining.The relative m RNA expression levels of inflammatory cytokines and mucosal barrier associated proteins in intestinal tissue were measured by Realtime-PCR.All mice were then fed with normal diet until 8 weeks of age.Afterwards,offspring were treated with 2% DSS(Dextran Slfate Sodium)solution for 5 days.Disease activity index(DAI)scoring system,H&E staining and histological damage score were used to assess the severity of colitis.Furthermore,the relative m RNA expression levels of inflammatory cytokines were also determined to evaluate the severity.Results1.At 2,3,4 weeks of age,the offspring in MHFD group were significantly heavier than those in MND group.No differences were found in the body weight between two groups at other measured time points.H&E staining showed the jejunum,ileum and colon length of 3-week old offspring in MHFD group were significantly decreased compared to those in MND group.The number of Ki-67 positive cells(18.00±4.74 vs 24.60±4.17;P<0.01)in each villus,goblet cells(14.70±2.91 vs 28.10±4.95;P<0.001)and MUC2 positive cells(20.60±3.13 vs 30.00±3.33;P<0.001)in each crypt were significantly lower than those in MND group.2.We utilized 16 S r DNA sequencing to characterize 3-week old offspring gut microbiota.The ? diversity differed significantly between 2 groups.Compared with MND group,MHFD significantly decreased ? diversity and the number of OTUs of offspring microbiota.At the phylum level of microbial composition between two groups,the relative abundance of Firmicutes was elevated while Bacteroidetes was reduced in MHFD group.In addition,MHFD increased the relative abundance of the Akkermansia and Escherichia/Shigella and decreased abundance of Butyricicoccus,Prevotellaceae,and Lachnospiracea_incertae_sedis at the genus level.3.Fluorescein isothiocyanate conjugated-dextran(FITC-D)method was applied to detect the intestinal permeability.The serum level of FITC-D in MHFD group was significantly higher(0.32±0.06 vs 0.16±0.13 ug/ml,P<0.05).Immunostaining of ZO-1 suggested that MHFD altered membrane localization of ZO-1 in colon.Compared with the 3-week old offspring mice in MND group,the relative m RNA expression of claudin(CLDN)1,3 and ZO-1 were significantly suppressed in MHFD group.4.H&E staining showed no obvious microscopic inflammation in both groups of 3-week old offspring mice,however,the relative expression levels of IL-1?,IL-6,and TNF-? m RNA were significantly higher in the MHFD group.5.The 8-week old offspring mice of two groups were treated with 2% DSS for 5 days.DAI score was significantly higher in MHFD group at day 3,4,and 5 after DSS treatment and significant shortening of colon length was observed consistently compared with MND group.The enhancement of colitis in MHFD group was confirmed histologically by H&E staining.Additionally,the inflammation/injury score in MHFD group were significantly higher than MND group.Elevated expression of IL-6,KC,and TNF-? was observed in MHFD group,as compared with MND group.ConclusionOur results showed that MHFD altered intestinal development and cell proliferation,induced dysbiosis and low grade inflammation and disrupted mucosal barrier function in offspring mice.More importantly,MHFD enhanced the susceptibility of offspring to DSS-induced colitis in adulthood.