Prenatal Maternal Stress Exacerbates Colitis Of Offspring Mice In Adulthood

Background and Objective: The global incidence of Inflammatory bowel disease(IBD)is increasing,but the mechanisms are not fully understood.Recent studies suggest that early life events may increase the risk of IBD.Early life(from gestation to 2 years after birth)is a critical period for growth and development.Numerous studies have shown that early life events can affect the establishment of normal gut flora,alter cellular functions in a long term and thus have a far-reaching impact on body health and disease risk.Stress is known to alter gut microbiota and induce gut inflammation.Prenatal maternal stress(PNMS)has been reported to induce dysbiosis,perturb neuroimmune network and upregulated placental inflammatory factors levels,and may increase the risk of asthma,visceral hypersensitivity and neurological disorders and other diseases in offspring through vertical transmission.Previous studies have suggested that PNMS can change gut gene expression and immune cell recruitment in fetal mice.However,it is not clear whether PNMS increases the susceptibility of offspring to colitis.The study aims to explore the effect of PNMS on the risk of colitis in adult offspring mice and possible mechanisms.Methods: C57BL/6 pregnant mice were randomly divided into PNMS group and Control group.Dams in PNMS group received chronic variable stress from the 10 th to 18 th day of pregnancy,while control mice did not do any treatment.Vaginally delivered newborn mice were raised with their mothers,and then separated after 3-weeks of lactation.Record the weight of offspring.Feces of 3-week-old mice were collected and some of the mice were sacrificed.Remaining mice were raised until 8 weeks old,and then 2% dextran sodium sulfate(DSS)was used to colitis modeling for 5 days.Methods for sacrificed mice are as follows:(1)Gut development,barrier,inflammation and microbiota were evaluated in 3-week-old offspring: mucosal morphology and villus length/crypts depth were observed by HE staining,intestinal cell proliferation was evaluated by Ki-67 immunohistochemical staining,goblet cell differentiation was evaluated by periodate Schiff(PAS)staining and mucin-2(MUC2)immunohistochemical staining,and gut permeability was detected by FITC-D method.Immunofluorescence staining was used to observe the expression of ZO-1 and Ig A,PCR to detect the expression of tight junction proteins,PCR to detect the expression of inflammatory factors,and 16 S r DNA sequencing to analyze fecal flora.(2)The severity of colonic inflammation in 8-week-old offspring: disease activity index(DAI)scores,lengths of colon,FITC-D method and histopathological injury scores were recorded;and expressions of inflammatory factor m RNA were assayed by PCR.Results:(1)No statistically significant difference in postnatal weight between the two groups Compared with Control group,the villi length/crypt depth of the 3-week-old offspring mice in PNMS group were significantly decreased.Ki-67 positive cells of villi,MUC2 positive cells and PAS positive cells of colon were decreased.(2)FITC-D concentration of 3-week-old PNMS mice was higher than that in Control mice,indicating increased intestinal permeability.The ZO-1 membrane localization expression and s Ig A positive cells was decreased in PNMS mice.The expression of ZO-1,Occludin,and Claudin3 in PNMS mice was lower than that of Control mice.(3)HE staining of 3-week-old offspring showed no significant intestinal inflammatory changes,while the colonic IL-1β,IFN-γ and TNF-α in PNMS mice increased.(4)Bifidobacterium,Blautia,and Robinsoniella were reduced in the 3-week-old PNMS offspring,while Desulfovibrio,Streptococcus and Enterococcus were increased.(5)After 5 days of DSS treatment at the age of 8 weeks,all adult mice showed signs of weight loss and hematochezia.DAI scores of PNMS group were significantly higher than those of Control group on the last 3 days.Compared with Control group,colitis mice with PNMS had higher FITC-D concentration,shorter colon length,higher histopathological injury scores and inflammatory factors levels.However,there was no significant difference in FITC-D concentration between two groups without DSS.Conclusion: PNMS could inhibit gut development,damage the gut barrier function,cause dysbiosis,induce low-grade gut inflammation,and exacerbate experimental colitis in offspring in adulthood.This study provides an experimental basis for adverse events in early life to increase the risk of IBD in adulthood,and is of great significance for exploring the pathogenesis of IBD and setting future prevention goals.