Melatonin in the colon modulates intestinal microbiota in response to stress and sleep deprivation

Abstract

Background/aims: Stress is closely related to the deterioration of digestive disease. Melatonin has potent anti-inflammatory properties. The objective of this study was to determine the effect of water stress (WS) and sleep deprivation (SD) on intestinal microbiota and roles of melatonin in stressful condition.

Methods: We used C57BL/6 mice and specially designed water bath for stress and SD for 10 days. We measured melatonin concentrations in serum, feces, and colon tissues by high-performance liquid chromatography. Genomic DNA was extracted from feces and amplified using primers targeting V3 to V4 regions of bacterial 16S ribosomal RNA genes.

Results: Compared to the control, melatonin concentration was lower in the WS and SD. Fecal concentration was 0.132 pg/mL in control, 0.062 pg/mL in WS, and 0.068 pg/mL in SD. In colon tissue, it was 0.45 pg/mL in control, 0.007 pg/mL in WS, and 0.03 pg/mL in SD. After melatonin treatment, melatonin concentrations in feces and colon tissue were recovered to the level of control. Metagenomic analysis of microbiota showed abundance in colitogenic microbiota in WS and SD. Melatonin injection attenuated this harmful effect. WS and SD showed decreased Lactobacillales and increased Erysipelotrichales and Enterobacteriales. Melatonin treatment increased Akkermansia muciniphila and Lactobacillus and decreased Bacteroides massiliensis and Erysipelotrichaceae.

Conclusions: This study showed that stress and SD could affect intestinal dysbiosis and increase colitogenic microbiota, which could contribute to the aggravating digestive disease. Melatonin concentrations in feces and colon tissue decreased under WS and SD. Melatonin treatment brought recovery of melatonin concentration in colon tissue and modulating dysbiosis of intestinal microbiota.

Keywords: Gastrointestinal microbiome; Melatonin; Psychological stress; Sleep deprivation.

Fig. 1.

Schematic diagram of the experiment design. Group I (n=6): control. Group II (n=6): water stress: these mice were housed in a specially designed water bath for stress for 10 days. Group III (n=6): water stress+melatonin, melatonin at a dose of 10 mg/kg was administered to these mice intraperitoneally for 10 days. Group IV (n=6): water stress+sleep deprivation. The experiment was divided into normal sleep group and sleep deprivation group by differentiating the radius of the plat form in which the mouse was sitting in the water bath. Group V (n=6): water stress+sleep deprivation+melatonin.

Fig. 2.

Animal experimental results. (A) Changes in body weight in each group. Stress induced significant weight loss without intestinal histologic change. No significant reduction in weight loss during water stress was observed even though melatonin administration. (B) Colon length in each group. (C) Histological analyses of colon (H&E, ×100). There were no significant changes in colon length or microscopic inflammatory change. WS, water stress; SD, sleep deprivation; M, melatonin.

Fig. 3.

Measurement of melatonin concentration in each group. (A) Serum, (B) feces, and (C) colon tissues. ^aCompare with control, WS, WS+SD; ^bCompare with control, WS+M, WS+SD+M. WS, water stress; SD, sleep deprivation; M, melatonin.

Fig. 4.

Analysis of intestinal microbiota in each group. (A) In water stress and/or sleep deprivation, there were significantly increased abundance in order of colitogenic microbiota such as Enterobacteriales and Erysipelotrichales. (B) No significant change in the Richness, Shannon index, Simpson index, or the number of operational taxonomic units (OTUs) among groups. (C) Increased abundance of Proteobacteria and Bacteroidetes at phylum level in water stress and/or sleep deprivation group (inner circle: phylum; outer circle: species). WS, weight loss; SD, sleep deprivation; M, melatonin.

Fig. 5.

Compared relative abundant species in intestinal microbiota among each group. LDA, linear discriminant analysis; WS, water stress; SD, sleep deprivation.

Fig. 6.

(A-D) At species level, water stress (WS) with sleep deprivation (SD) group showed significant change such as decreased abundance of Lactobacillus murinus and increased abundance of Bacteroides massiliensis. Clostridium cocleatum group, Enterobacter asburiae group (P<0.05 by Kruskal-Wallis H test). ^aP<0.05.

Fig. 7.

Changes in intestinal microbiota after melatonin treatment. (A, B) Administration of melatonin resulted in changes such as increased abundance of Akkermansia muciniphila and Lactobacillus but decreased abundance of Bacteroides massiliensis, and Erysipelotrichaceae (P<0.05 by Kruskal-Wallis H test). ^aP<0.05. WS, water stress; M, melatonin; SD, sleep deprivation.