ABSTRACT
ObjectiveTo investigate the effect of Loulianwan on the gut microbiota of db/db mice with type 2 diabetes mellitus （T2DM）. MethodMale db/m+ mice aged 4-5 weeks were assigned to the normal group， and male db/db model mice of the same age were randomly divided into model group， metformin group （0.25 g·kg-1·d-1）， and Loulianwan group （13 g·kg-1·d-1）， with six mice in each group. Drug intervention lasted five weeks. The body weight， water intake， and fasting blood glucose （FBG） of the mice were recorded every week. After five weeks， the FBG， liver triglyceride （TG）， liver total cholesterol （TC）， glycated serum protein （GSP）， and fasting serum insulin （FINS） were detected， and the insulin resistance index （HOMA-IR） was calculated. The feces in the mouse intestines were collected， and the 16S rRNA sequencing technology was used to detect the structural changes in the fecal gut microbiota of mice in each group. ResultCompared with the normal group， the model group showed increased body weight， water intake， FBG， liver TG， liver TC， GSP， FINS， and HOMA-IR （P<0.01）. Compared with the model group， the Loulianwan group showed reduced water intake， FBG， liver TG， liver TC， GSP， FINS， and HOMA-IR （P<0.01）. The gut microbiota in the Loulian Lills group changed from phylum to genus level. The relative abundance of beneficial bacteria increased and the relative abundance of harmful bacteria decreased. Among them， the abundance of Akkermansia muciniphila， Blautia， Ruminococcus， and Parabacteroides increased （P<0.01）. ConclusionLoulianwan can significantly improve glucose and lipid metabolism in db/db mice with T2DM， and its mechanism may be related to the increase in the abundance of Akkermansia muciniphila， Blautia， Ruminococcus， and Parabacteroides in the intestine.
ABSTRACT
OBJECTIVE@#To explore the effects of oral exposure to titanium dioxide nanoparticles (TiO2 NPs) on the composition and structure of human gut microbiota.@*METHODS@#The particle size, shape, crystal shape and degree of agglomeration in ultrapure water of TiO2 NPs were characterized. The in vitro human digestive tract microecological simulation system was established by simulating the fluid environment and physical conditions of stomach, small intestine and colon, and the stability of the simulation system was evaluated. The bacterial communities were extracted from human feces and cultured stably in the simulated system. They were exposed to 0, 20, 100 and 500 mg/L TiO2 NPs, respectively, and the bacterial fluids were collected after 24 h of exposure. The effect of TiO2 NPs on the composition and structure of human gut microbiota was analyzed by 16S rRNA sequencing technology. Linear discriminant analysis effect size (LEfSe) was used to screen differential bacteria, and the Kyoto encyclopedia of genes and genomes (KEGG) database for functional prediction.@*RESULTS@#The spherical and anatase TiO2 NPs were (25.12±5.64) nm in particle size, while in ultra-pure water hydrated particle size was (609.43±60.35) nm and Zeta potential was (-8.33±0.22) mV. The in vitro digestive tract microecology simulation system reached a relatively stable state after 24 hours, and the counts of Enterococci, Enterobacte-rium, and Lactobacillus reached (1.6±0.85)×107, (5.6±0.82)×107 and (2.7±1.32)×107, respectively. 16S rRNA sequencing results showed that compared with the control group, the number and evenness of gut microbiota were not significantly affected at phylum, class, order, family and genus levels in TiO2 NPs groups (20, 100 and 500 mg/L). The relative abundance of some species was significantly changed, and a total of 42 different bacteria were screened between the TiO2 NPs groups (20, 100 and 500 mg/L) and the control group [linear discriminant analysis(LDA) score>3], represented by Enterobacter, Bacteroidaceae, Lactobacillaceae, Bifidobacteriaceae and Clostridium. Further predictive analysis of gut microbiota function showed that TiO2 NPs might affect oxidative phosphorylation, energy meta-bolism, phosphonate and phosphonate metabolism, and methane metabolism (P < 0.05).@*CONCLUSION@#In human digestive tract microecological simulation system, TiO2 NPs could significantly change the composition and structure of human gut microbiota, represented by Enterobacter and probiotics, and may further affect a variety of metabolism and function of the body.