关键词: 产肠毒素大肠杆菌K88, 嗜黏蛋白阿克曼菌, 回肠, 凋亡, 自噬

Abstract: To investigate the effect of Akkermansia muciniphila (AKK) on the expression of genes related to apoptosis and autophagy signaling pathways in the ileum after toxinogenic Escherichia coli (ETEC) K88 stimulation induces intestinal injury, 18 female BALB/c mice (5~6 weeks old, weighing 18±1 g) were randomly divided into 3 treatment groups, each treatment with 6 replicates. After 1 week of normal feeding, the mice were orally gavaged with PBS, live AKK bacteria, or heat-inactivated AKK bacteria. The gavage was performed once every 2 d, and after 2 weeks of continuous gavage, ETEC K88 bacterial solution was intraperitoneally injected for infection, and after 36 h, the mice were anesthetized and sacrificed, and intestinal samples were retrieved to detect the expression of genes related to apoptosis and autophagy signaling pathway. The results showed as follows: (1) AKK bacteria and inactivated AKK bacteria had alleviating effects on the damage of ileal morphology and structure caused by ETEC K88 infection. (2) Both gavage and inactivated AKK significantly down-regulated the mRNA expression of interleukin IL-1β, IL-6 and tumor necrosis factor-α (TNF-α) in the ileum of mice (P<0.05). (3) AKK significantly reduced the mRNA expression levels of Fasl, Caspase 3, Caspase 9 and Bcl-2-related X protein (Bax), which are related to the apoptosis signaling pathway in mice, (P<0.05). (4) AKK bacteria or inactivated AKK bacteria significantly reduced the mRNA expression levels of mammalian lepatoxin target protein (mTOR), and autophagy-related gene 12 (Atg12) in the ileum of mice (P<0.05). AKK bacteria has a certain alleviating effect on ileal injury in mice caused by ETEC K88 infection.

Key words: toxinogenic, Escherichia coli K88, Akkermansia muciniphila, ileum, apoptosis, autophagy