Effects of compound fermented milk on improving constipation in mice and underlying mechanism / 中华微生物学和免疫学杂志

ABSTRACT

Objective:To investigate the effects of compound fermented milk on intestinal microbiota, short chain fatty acid (SCFA), intestinal motility and mucosal barrier in mice with constipation.Methods:Twenty-seven C57BL/6JNifdc mice were randomly divided into three groups control group, model group and intervention group. The model group and the intervention group were given loperamide intragastrically for two weeks. Starting from the second week, the intervention group was treated with compound fermented milk for 7 d. The control group was given normal saline. Food intake, water intake, weight change, fecal moisture content, time of first-time black stool and small intestine propulsion rate were detected. Expression of serotonin C receptor (5-HTR2C), zona occludins-1 (ZO-1) and mucin-2 (MUC-2) at mRNA level in colon was analyzed. Western blot was used to measure the expression of Raf/ERK/MAPK-related proteins. SCFA level in intestinal tract was detected by gas chromatography. Intestinal microbiota diversity was analyzed by high-throughput sequencing.Results:Compared with the control group, the first black stool excretion time was significantly prolonged in the model group ( P<0.01). Moreover, fecal moisture content, small intestine propulsion rate and the expression of 5-HTR2C and ZO-1 at mRNA level in colon were significantly decreased ( P<0.01). Compared with the model group, the first black stool excretion time was significantly shortened ( P<0.05); fecal moisture content, small intestine propelling rate ( P<0.05), the expression of colon 5-HTR2C and ZO-1 at mRNA level ( P<0.05), phosphorylation of Raf/ERK/MAPK pathway in the colon, intestinal SCFA-producing bacteria and intestinal SCFA content were increased in the intervention group. Conclusions:Compound fermented milk had a therapeutic effect on constipation in a mouse model by increasing the abundance of SCFA-producing bacteria and SCFA content, enhancing the phosphorylation of the Raf/ERK/MAPK pathway to up-regulate the expression of 5-HTR2C at mRNA level in the colon, and increasing the expression of ZO-1 at mRNA level in the colon. Intestinal peristalsis and intestinal mucosal barrier function were enhanced, thus improving the symptom of constipation.