[Effects of high-fat diet on gut microbiota in rats transplanted with gut microbiota from normal/high triglyceridemic individuals].

OBJECTIVE

Using sterile SD rats as a model, the fat accumulation and changes in the intestinal flora of rats transplanted with normal/high triglyceride(TG) population under high-fat diet were studied.

METHODS

10-week-old male sterile rats were randomly divided into 3 groups according to body weight, with 6 rats in each group. The non-colonizing group was gavaged with normal saline, the normal lipid group was gavaged with normal TG(<1.7 mmol/L) human intestinal flora, and the high TG group was gavaged with high TG(≥1.7 mmol/L) human intestinal flora. Rats were given fecal bacterial solution by gavage at a dose of 1 mL per 100 g of body weight, every other day, for a total of 3 times, followed by 2 weeks of adaptive growth of the microbiota. After the transplanting was completed, a 9-week feeding experiment with high-fat diet(fat energy supply ratio 40.5%) was conducted. The body weight of the rats was measured weekly, and feces were collected every three weeks. After the experiment, liver, perirenal, subcutaneous and brown fat were weighed. The fat weight was used to represent the fat accumulation of the rats, and lipid indicators were determined. Liver HE staining was used to observe steatosis, and high-throughput sequencing was used to analyze the intestinal flora of the rats.

RESULTS

After the experiment, compared with the colonized normal TG population microbiota group, there were no significant differences in body weight, perirenal, subcutaneous and brown fat mass, and blood lipid levels in the colonized high TG microbiota group. Liver HE staining sections showed that both the colonized high TG and non-colonized dyslipidemia microbiota groups could observe more severe steatosis and obvious fat vacuums. The intestinal microbiota profiles of the two groups of rats colonized with different population microbiota showed different variation patterns at the phylum and genus levels. At 0 weeks of high-fat diet, the F/B ratios of the microbiota phylum in rats colonized with the feces of the high-TG population and those colonized with the feces of the normal TG population were 1.24 and 0.48, respectively. After 9 weeks of high-fat diet, The F/B ratios of the Firmicutes and Bacteroidetes phyla of the bacteria phyla in rats colonized with the feces of the high TG population and those colonized with the feces of the normal TG population were 3.37 and 0.81, respectively. In the fecal colonization group of rats in the high TG population under a high-fat diet, more obvious intestinal flora disorders occurred, the relative abundance of beneficial bacteria was inhibited, and the relative abundance of pathogenic bacteria increased.

CONCLUSION

Under high-fat diet, the colonization of intestinal flora in volunteers with different blood lipid levels has a certain relationship with the weight changes and fat accumulation of rats. The species composition and abundance of flora in different populations have undergone significant changes.