Mechanism Of Maternal High Salt Diet On Non-alcoholic Fatty Liver Disease In Mice Offspring

Epidemiological studies have revealed a link between a high salt intake and nonalcoholic fatty liver disease(NAFLD)in adults.However,whether a maternal high-salt diet can induce NAFLD in offspring remains unknown.In this study,we investigated the effect and mechanism of maternal high-salt diet on NAFLD in offspring,and explored the role of gut microbiota and deoxycholic acid(DCA).Part Ⅰ: Maternal High Salt Diet Caused NAFLD in OffspringObjectives: We respectively investigated the effect of high-salt diet on NAFLD in different periods(pregnancy,lactation and perinatal period).Methods: In the present study,mice were divided into four groups: control group and maternal high-salt diet during the pregnancy,lactation and perinatal period.Body weights of the offspring were measured,and the blood and liver tissues of the offspring were collected at the age of 3 and 12 weeks.Liver pathology and molecular changes were evaluated.Results: Compared with the control group,maternal high-salt diet during the perinatal period caused the pathological features of NAFLD in the liver of the offspring at 3 weeks,and increased the contents of TC and TG in liver and serum(1.22～2.32 fold increase,p <0.05),the expressions of hepatic lipid synthesis genes(Srebp1c,Fas and Acc)and proinflammatory cytokine(Tnfα and Il6)(1.63～3.15 fold increase,p < 0.05)in offspring at the age of 3 weeks.The NAFLD phenotype was more significant at 12 weeks.Maternal highsalt diet during the lactation increased the contents of TG in liver and serum,the expressions of hepatic Il6 and Tnfα(1.77～2.14 fold increase,P < 0.05)at the age of 3 weeks.At the age of 12 weeks,maternal high-salt diet during the lactation induced NAFLD lesions.However,maternal high-salt diet during the pregnancy only induced NAFLD lesions in the offspring at 12 weeks.Conclusion: Maternal high-salt diet during the perinatal period caused the unique characteristics of NAFLD at the age of 3 weeks,which was more severe than maternal highsalt diet during pregnancy and lactation caused adult offspring to develop NAFLD phenotype.Part Ⅱ: Mechanism of Gut Microbiota and Deoxycholic Acid on NAFLD in Offspring Induced by Maternal Perinatal High Salt DietObjectives: High-salt diet can lead to intestinal microbiota disorder involved in DCA transformation,and DCA plays an important role in NAFLD by inhibiting hepatic FXR and upregulating its downstream gene pathway.Therefore,this part elucidates the role of gut microbiota and DCA on NAFLD in offspring induced by maternal perinatal high salt diet.Methods: In view of the role of probiotics(VSL#3,including lactobacillus,bifidobacterium and streptococcus)in restoring microbial homeostasis and reducing the pathological model of NAFLD,VSL#3,DCA and FXR activator(OCA)were used to intervene the offspring,and elucidate the mechanism of gut microbiota and DCA in maternal high-salt diet during the perinatal induced NAFLD in the offspring.The intestinal microbiota,blood and liver fat,liver pathology and gene expression of the offspring at 3weeks were analyzed.Results:(1)Compared with the control group,maternal high-salt diet during the perinatal resulted in NAFLD in the offspring,increased the abundance of Bacteroides(p <0.05),the levels of fecal DCA(1.8～3.96 fold increase,p < 0.05).In addition,maternal highsalt diet during the perinatal decreased the hepatic FXR signaling(Cyp7a1,Fxr and Shp)(0.44～0.74 fold increase,p < 0.05)in offspring compared with the control group.(2)Compared with maternal high-salt diet group,maternal HSD+offspring VSL#3 intervention alleviated the progress of NAFLD in offspring.In addition,maternal HSD+offspring VSL#3 intervention decreased the expression of downstream genes(Srebp1c,Acc and Tnfα)of liver FXR signaling pathway(0.25～0.61 fold increase,P < 0.05).On the basis of maternal high-salt diet+offspring VSL#3,DCA intervention in offspring increased the expression of downstream genes(Srebp1c,Fas,Acc,Tnfα and Il6)of hepatic FXR signaling pathway(1.62～2.81 fold increase,P < 0.05).Administration of OCA,an FXR activator,decreased the expression of downstream genes of hepatic FXR signaling pathway(P < 0.05).Conclusion: Maternal high-salt diet during the period increased the Bacteroides and DCA levels,which were related to changes the FXR signaling pathway in offspring.Part Ⅲ: Probiotics Intervention in Reducing NAFLD in Offspring Induced by Maternal Perinatal High Salt DietObjectives: We investigated the intervention experiment of maternal probiotics was conducted to improve NAFLD in offspring caused by maternal perinatal high salt diet.Methods: Mice were divided into three groups: control group,maternal high-salt diet during perinatal period group and maternal high-salt diet+maternal VSL#3 group.At the age of 3 weeks,the biological samples of offspring were collected to study the mechanism of maternal VSL#3 improving NAFLD in offspring.Results: Maternal HSD+VSL#3 intervention during the perinatal period alleviated the progress of NAFLD in offspring,and decreased the contents of TC and TG in liver and serum(0.45～1.44 fold decrease,p < 0.05),the expressions of hepatic Srebp1 c,Fas,Acc,Tnfα and Il6(0.47～0.76 fold decrease,p < 0.05),the abundance of Bacteroides and levels of DCA in offspring(0.41～0.72 fold decrease,P < 0.05).Conclusion: Maternal probiotics VSL#3 intervention alleviated the progress of NAFLD induced by maternal high-salt diet during the perinatal.