Abstract
Purpose :
It has been shown that light exposure during the night time is associated with body weight gain in both rodent and human. However, it is unclear which photoreceptor is providing the light information for modulating the body metabolism. In addition, gut microbiota shows daily oscillation in mice. Whether light dark cycle could influence the daily rhythm of gut microbes is also unclear.
Methods :
To compare gut microbiota composition between normal light dark cycle and light exposure at night, we measured the body weight gain and collected fecal samples from mice housed under both conditions for two weeks. The 16SrRNA metagenomic sequencing and analysis were performed to compare the gut microbiota between wild type animal housed under normal light dark cycle and light exposure at night. The determine whether ipRGCs are involved in this light dependent modulation, melanopsin knockout and ipRGC elimination mice were used with the same procedure.
Results :
We found that light exposure at night influenced the gut microbiota composition and enhanced body weight gain. However, the light-induced body weight gain was completely blocked in melanopsin knockout or ipRGC-elimination mice. In addition, light exposure at night can not modulate some features of gut microbiota such as composition in melanopsin knockout mice.
Conclusions :
Light dark cycle information transmitted by ipRGC can influence the body metabolism and gut microbiota. Therefore, in addition to food and the circadian clock system, the external light signal is involved in shaping the gut microbiota.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.