ω-3 Polyunsaturated Fatty Acids Protect Against NAFLD Progression Modificating Gut Microbiota

Non-alcoholic fatty liver disease(NAFLD),the hepatic feature of the metabolic syndrome,is the most prevalent chronic liver diseases in developed countries and urban population of China.Epidemiological studies have demonstrated consumption of ω-3 polyunsaturated fatty acids(PUFAs)enriched fish oil or perilla oil protected against NAFLD progression and ameliorated hepatic damage and inflmmation,but the mechanisms remained unclear.Recent studies indicated the modification of gut microbiota plays an important role in the progression from simple steatosis to steatohepatitis.Objective:High fat and cholesterol diet feed Sprague Dawley(SD)male rats,to establish the animal model of NAFLD,observe fish oil and perilla oil rich in ω-3 PUFAs attenuated NAFLD in rats and investigate the impacts of ω-3 PUFAs on gut microbiomes in high fat diet(HFD)induced rat NAFLD model.Methods : In the present study,male Sprague-Dawley(S-D)rats were(8-9 weeks old weighing 180～200 g)randomly allocated to four groups(10 animals per group),and each group was fed one of the following four diets for 16 weeks: normal chow die(NOR group)and three western style high fat diet: lard-rich diet(HFD group),fih-oil-rich diet(FOH group),or perilla-oil-rich diet(POH group).At the end of 16 th weeks feeding,we sampled their feces and plasma was collected.Liver was quickly removed and weighed.Serum TCH,TG,LDL-C,ALT and AST were determined using respective diagnostic kits.The fixed liver tissues were embedded in paraffin and sectioned at 5 μm thickness,stained with hematoxylin and eosin.Then,we qualifed hepatic proinflammatory cytokine.We adopted 16 S rRNA amplicon sequencing technique to investigate the impacts of fish oil and perilla oil on gut microbiomes in high fat diet(HFD)induced rat NAFLD model.To verify the relative abundance of Akkermansia and Escherichia between groups,we performed 16 S rDNA gene-targeted q PCR.Results: Both fish oil and perilla oil can relieve High-fat-induced hepatic steatosis and inflammation.In comparison with the low-fat control diet(NOR),HFD feeding significantly increased the relative abundance of Gram-negative bacteria in the gut,which was slightly trifling by either perilla oil or fish oil.Because TLR4 is the key pattern-recognition receptor of LPS,the hepatic expression of TLR4 in POH group and FOH group was both signifiantly lower than HFD group indicates n-3 PUFAs consumption reduced hepatic LPS level,which is coincident with the microbiome data.Additionally,fish oil and perilla oil consumption abrogated the elevated abundance of Prevotella and Escherichia in the gut from HFD fed animals.Moreover,fish oil and perilla oil consumption has similar composition of gut microbiomes.Interestingly,the relative abundance of anti-obese Akkermansia was remarkably increased only in animals fed fish oil compared with HFD group.Conclusions: Through the researches above,in this study we compared the different effects of ALA enriched perilla oil and DHA/EPA enriched fish oil on HFD-induced metabolic disorder and gut dysbiosis,and we found ω-3 PUFA may ameliorate HFD-induced hepatic inflammation via both reducing the abundance of Gram-negative germs in intestinal and suppressing Gram-negative germs induced inflmmation in liver.And our findings will help to understand the nutritional benefits of ω-3 PUFA on health.