Is blue light exposure a cause of precocious puberty in male rats?

Abstract

PurposeOur study aimed to examine the effects of blue light exposure on prepubertal male rats’ puberty and testis tissue.MethodsEighteen 21-day-old male Sprague Dawley rats were divided into three groups consisting of six rats in each group: Control Group (CG), Blue Light-6 hours (BL-6), and Blue Light-12 hours (BL-12). CG rats were maintained with 12/12-hour light-dark cycles. The rats of BL-6 and BL-12 were exposed to blue light (450-470nm/irradiance level 0.03uW/cm2) for 6 hours and 12 hours, respectively. Rats were exposed to blue light until the first signs of puberty. The ELISA method was used to analyze the serum levels of FSH, LH, testosterone, DHEA-S, leptin, ghrelin, melatonin, glutathione, glutathione peroxidase, and malondialdehyde. Testes were dissected for histomorphological examination.ResultsThe medians of the pubertal entry days of the CG, BL-6, and BL-12 were 38th, 30th, and 28th days, respectively. (p:0.001) The FSH, LH, and testosterone concentrations of all groups were similar. The FSH concentration increased as the LH concentration increased (r: 0.82 p: 0.001). The serum LH concentration increased as serum testosterone, and DHEAS decreased, respectively (r: -0.561, p: 0.01) (r:-0.55 p:0.01). Testicular lengths and weights of the BL groups were smaller compared to CG (p: 0.03),(p: 0.04). GPx was higher for BL-6 and BL-12 than the CG (p:0.021, p:0.024). Testis tissue was compatible with the pubertal period in all groups. As the blue light exposure time increased, spermatogenesis was suppressed, and capillary dilatation and edema in the testis tissue increased.ConclusionOur study is the first to show the effects of blue light exposure on male rats’ puberty process. And we showed that exposure to blue light and the duration of exposure lead to precocious puberty in male rats. The blue light exposure suppressed spermatogenesis, marked vasodilatation in the interstitial area of the testis, and disrupted the integrity of the basement membrane. These findings intensified with increasing exposure time.

Effects of Pinealectomy and Melatonin Supplementation on Elements Metabolism in Rat Testicular Tissue

“…MEL, which plays a role in the sleep-wake cycle, is also a powerful antioxidant that clears free radicals directly and indirectly [2]. MEL, which also serves as a control mechanism that prevents the early onset of puberty, is closely related to the reproductive system [3]. High concentrations of the MEL lead • Taken together, the results of our study highlight the important relationship between pineal gland and testicular element metabolism.…”

Periadolescent Blue Light Exposure and Brain Development: A CURS Proposal

“…Both BL-6 and BL-12 groups presented with precocious PO. Examination of the male testes and female ovaries post-mortem also showed morphological abnormalities with control counterparts in gonad vascularity as well as decreased sperm production (males) [3,10].…”

“…For blue light emission, a BL LED strip ((FSHI.1048.B020.6012, HI-LED, FLEX honor): 450-470nm/irradiance level 0.03uW/cm2 will be used. This wavelength and power density has been shown to not induce retinal damage [3,10]. The standard assigned housing units (polysulfide 65 X 24 X 15 cm cages) will be placed underneath the strip 20cm above in the center.…”

“…The standard assigned housing units (polysulfide 65 X 24 X 15 cm cages) will be placed underneath the strip 20cm above in the center. Unlike [3,10], no spectroradiometer will be used to measure irradiance due to budget constraints.…”

“…First, prolonged BL exposure elicited early pubertal onset (precocious PO) in both male and female rats. In the protocol by [3,10], both cohorts were exposed to BL LED strips for either 6 (BL-6) or 12 (BL-12) hours. Both BL-6 and BL-12 groups presented with precocious PO.…”