Investigating the Effect of Light on Circadian Rhythms and their Association with PCOS Using Animal Model

Abstract

Polycystic ovarian syndrome (PCOS) is the most prevalent metabolic and endocrine disorder in reproductive women. Under environmental conditions of constant light and light pollution, individual’s circadian rhythms are disturbed, which represents an emerging risk factor for PCOS, as it causes reproductive and metabolic changes in a body. In this study, a correlation between altered circadian rhythms and PCOS has been studied. In vivo analysis of PCOS was performed by exposing Wistar Rats to constant light for twenty- four hours. The two L/L groups of rats were exposed to different light intensities i.e., 240W for 16 weeks and 600W for 8 weeks. In comparison, L/D animal models were kept under twelve-hour light and twelve-hour dark cycle. Following observations have been made when animal models were tested for behavioral analysis. Rats under constant light showed symptoms of anxiety and loss of memory when tested by Elevated Maze Test and Morris Water Maze Test with P values of <0.0001. It is followed by high concentrations of androgens with P value of ˂0.0006, gonadotropin hormones with P value of <0.0001, anti mullerian with P value of ˂0.01, insulin with P value of ˂0.0002, and stress hormones cortisol with P value of ˂0.04 observed in the continuous light- induced animal models, as animal model showed evidence of disrupted circadian rhythms and PCOS. The histopathological analysis of ovaries, liver, and kidney showed that organs appeared damaged by the effect of environmental stress of constant light and PCOS. The current findings suggest that besides genetic and metabolic factors, PCOS can be caused by certain environmental factors which are prevalent in common population.