复合益生菌对非酒精性脂肪性肝病的作用及机制研究OA

Objective To evaluate the protective effects of probiotics against high-fat diet(HFD)-induced non-alcoholic fatty liver disease(NAFLD)and to explore potential mechanisms involving the regulation of the gut microbiota.Methods Thirty-six female SD rats were divided into control group,HFD group,DM9054 group,86066 group,N1115 group and a composite probiotic group,with six rats in each group,using a random number table.With the exception of the control group,the other five groups were used to establish a rat NAFLD model using an HFD.The control and HFD groups were administered 0.9％sodium chloride solution,whilst the probiotic groups were administered the corresponding bacterial strain of Lactobacillus rhamnosus DM9054,L.plantarum 86066,L.paracasei N1115 and the probiotic complex at a concentration of 1 × 1010 CFU/mL via oral gavage,once daily for 12 weeks.Body weight,Lee index,hepatic index and blood biochemical parameters were recorded for rats in each group;Liver tissue pathological changes were examined using oil red O and haematoxylin-eosin(HE)staining;the relative mRNA and protein expression levels of Toll-like receptor 4(TLR4),myeloid differentiation factor 88(MyD88)and nuclear factor-kappa B(NF-κB)in liver tissue were detected using qRT-PCR and Western blot;16S rRNA sequencing was employed to analyze changes in the composition and structure of the gut microbiota.Results All parameters in the control group of rats were normal,with no accumulation of lipid droplets or pathological changes observed in the liver tissue.Compared with the control group,the HFD group exhibited significant increases in body weight,Lee index,hepatic index,blood lipid levels,inflammatory factors levels and the relative mRNA and protein expression levels of TLR/NF-κB pathway;Oil Red O staining revealed extensive accumulation of red lipid droplets in the liver tissue,whilst HE staining demonstrated diffuse steatosis,ballooning degeneration and inflammatory infiltration.Compared with the HFD group,all probiotic groups showed varying degrees of improvement in the aforementioned parameters;among them,the composite probiotic group was significantly superior to the individual probiotic groups in reducing final body weight,hepatic index,Lee index,blood lipid levels,inflammatory factor levels and the relative mRNA and protein expression levels of TLR/NF-κB pathway(all P＜0.05).Oil red O staining revealed the most pronounced reduction in lipid droplet accumulation,whilst HE staining showed that the hepatic cell structure was closest to normal,with the mildest steatosis and inflammatory infiltration.Furthermore,the relative abundances of bacteria such as g_Shigella,f_Prevotellaceae,g_Prevotella,f_Verrucomicrobiaceae,o_Verrucomicrobiales,p_Verrucomicrobia,c_Verrucomicrobiae and g_Akkermansia in the gut microbiota of rats in the composite probiotic group were significantly higher than those in the HFD group(P＜0.05).Conclusion Probiotics can reduce inflammation levels in rats with NAFLD and improve the composition of the gut microbiota;the regulatory mechanism may be linked to the TRL4/NF-κB pathway.