Augmentation of Gut Microbiome improves Melatonin concentration, Sperm Parameters and Testicular Steroidogenesis in Light-polluted Rat

Abstract

Altering the natural circadian rhythm by prolonged exposure to light is known to alter reproductive functions in many species 
including humans. However, it is not clear if augmentation of the gut microbiome can protect male reproductive function when 
exposed to light pollution. The current study was designed to investigate if the administration of probiotics (pro) will mitigate 
the disruptive effect of light pollution on melatonin concentration, semen parameters and testicular steroidogenesis in the rat.
Thirty male Sprague-Dawley rats were randomized into six groups (n=5) consisting of the no-Pro/12hrs group that had 12:12 hrs 
light:dark cycle only; the Pro/12hrs group that had 12:12 hrs light:dark cycle plus probiotic supplementation; the no-Pro/16hrs 
that had 16:8 hrs light:dark cycle; the Pro/16hrs that had 12:12 hr light:dark cycle in addition to probiotic supplementation; the 
no-Pro/24hrs that had 24:0 hrs light:dark cycle; and the Pro/24hrs that had 24:0 hrs light:dark cycle plus probiotic 
supplementation. Each animal in the probiotic groups was fed a 10×106 colony-forming unit of lactobacillus acidophilus and 
Bifidobacterium bifidum every other day. Experiment lasted for 21 consecutive days. Probiotic administration significantly 
(p<0.05) increased circulating levels of melatonin, testosterone, and estradiol compared with control and no-pro 16hrs and 24hrs 
light-polluted groups. Malondialdehyde (MDA) and corticosterone levels were significantly (p<0.05) reduced while antioxidants 
activities significantly (p<0.05) increased in the testis and epididymis. Sperm motility and concentration significantly (p<0.05) 
increased in the pro groups compared with control and no-pro groups. Augmentation of the gut microbiome might play a 
significant role in improving male reproductive function during light pollution.