Inhibitory Effect of Lactococcus lactis subsp. lactis HFY14 on Diphenoxylate-Induced Constipation in Mice by Regulating the VIP-cAMP-PKA-AQP3 Signaling Pathway.

AIM: The naturally fermented yak yogurt of pastoralists in the Tibetan Plateau, China, because of its unique geographical environment and the unique lifestyle of Tibetan pastoralists, is very different from other kinds of sour milk, and the microorganisms it contains are special. Lactococcus lactis subsp. lactis HFY14 (LLSL-HFY14) is a new lactic acid bacterium isolated from naturally fermented yak yogurt. The purpose of this study was to study the inhibitory effect of the bacterium on constipation. METHODS: Constipation was induced in ICR mice with diphenoxylate, and the constipated mice were treated with LLSL-HFY14. The weight and feces of the mice were visually detected. Colonic tissues were observed on hematoxylin and eosin-stained sections. Serum indices were detected with kits. mRNA expression in the colon was determined by quantitative polymerase chain reaction assay. RESULTS: Constipation caused weight loss, the number of defecation granules, defecation weight, fecal water content decreased, and the first black stool excretion time increased. LLSL-HFY14 alleviated these symptoms, and the effects were similar to those of lactulose (drug). The pathological examination revealed that constipation caused pathological changes in the colon, and LLSL-HFY14 effectively alleviated the disease. LLSL-HFY14 increased serum levels of motilin, gastrin, endothelin, substance P, acetylcholinesterase, and vasoactive intestinal peptide (VIP) and decreased serum levels of somatostatin in constipated mice. In addition, LLSL-HFY14 upregulated VIP, cAMP, protein kinase A, and aquaporin 3 expression in colonic tissues of constipated mice in a dose-dependent manner. CONCLUSION: LLSL-HFY14 inhibited constipation, similar to lactulose, and has the potential to become a biological agent.

Protective effect of mulberry (Morus atropurpurea) fruit against diphenoxylate-induced constipation in mice through the modulation of gut microbiota.

Mulberry (Morus atropurpurea) has long been used to treat gastro-intestinal ailments; however, the functional basis of its therapeutic effects remains unclear. The aim of this study was to measure the effects of mulberry (administered by gavage) on diphenoxylate-induced constipation in mice and elucidate the mechanisms underlying these effects using constipation and physicochemical indexes, histological morphology and 16S rDNA amplicon analysis of fecal microbiota. Sixty Kunming mice were randomly divided into the following six groups (n = 10 per group): normal control, constipation model, positive control, and low-, mid- and high-dose mulberry groups. After 14 days of treatment, constipation was induced over 5 days and measurements were conducted. The results show that mulberry treatment prevented constipation by increasing the fecal water content, shortening the first red fecal defecation time, promoting gastric evacuation, and increasing the gastric-intestinal transit rate (P < 0.05). Compared with the constipation model group, the mulberry-treated groups showed decreased aquaporin gene expression (Aqp3, Aqp4, Aqp8 and Aqp9), decreased serum levels of inhibitory neurotransmitters (nitric oxide and vasoactive intestinal peptide) (P < 0.05), and increased serum levels of excitability neurotransmitters (acetyl choline, substance P, and motilin). The histological morphology of the colon showed that mulberry treatment increased the number of mucus cells (P < 0.05). Mulberry treatment also increased the concentrations of acetic, propionic, butyric, valeric and isovaleric acids (P < 0.05), increased the abundance of Lactobacillus and Bifidobacterium in feces, and decreased the abundance of Helicobacter and Prevotellaceae in feces. Our findings indicate that mulberry consumption effectively prevents constipation in mice and is a promising therapeutic candidate for constipation.