White LED Light Exposure Inhibits the Development and Xanthophore Pigmentation of Zebrafish Embryo

Abstract

Circadian rhythm in all living organisms is disturbed continuously by artificial light sources and artificial lighting has become a hazard for public health. Circadian rhythm of melatonin maintains high levels of melatonin during the night and low levels during the day. N-acetyltransferase (arylalkylamine N-acetyltransferase, AANAT) is one of the four enzymes required for melatonin synthesis and mtnr1ba is a melatonin receptor-encoding mRNA that is expressed widely in the embryonic brain. Pax7 has important roles during neural crest development and especially xanthophore pigmentation. Due to its diurnal nature, zebrafish provide a special opportunity for research on circadian rhythms that are regulated by melatonin. Here in this study, we showed that when compared with the white light control group, white LED light exposure resulted in loss of yellow pigmentation, decreased body length and locomotor activity, oxidant-antioxidant imbalance and decreased expressions of aanat2 , mtnr1ba , and pax7 in zebrafish embryos. Histological analysis of this group revealed disorganization of the spaces among photoreceptor cells, decreased total retinal thickness and photoreceptor cell layer thickness compared with the control group. Artificial lighting pollution has the potential to become an important risk factor for different diseases including cancer especially for industrialized countries, therefore, more studies should be performed and necessary regulations should be made regarding this risk factor.

Effects of different wavelength from Light Emitting Diodes (LEDs) on growth and development in zebrafish (Danio rerio) embryos and larvae

“…Photoperiod (light-dark) is an external environmental factor that induces photoreceptive tools to adapt to photoreceptor sensitivity [49]. Aanat2 and mtnr1ba expression support melatonin production and photoperiod marker in vertebrates [13,44]. In our study, mtnr1ba and aanat2 were expressed in all wavelength treatments in response to the 14:10 LD time treatment given to all wavelength treatments.…”

“…Light might play a significant role in embryogenesis; blue light wavelengths ranging from 400 to 500 nm (near-ultraviolet) are suspected to be potentially harmful to cells (gametes and embryos). Some previous studies have concluded that blue light is most damaging, with damage causing as much as 100 % mortality in 72 hpf zebrafish embryos [44].…”

“…Melatonin-treated zebrafish embryos grow faster, and the melatonin receptor gene mtnr1ba plays a part in this. Melatonin promotes zebrafish growth by increasing cell proliferation in the embryo [44]. The arylalkylamine N-acetyltransferase (aanat) enzyme is a melatonin contributor and a rate-limiting enzyme in melatonin production.…”

Centella asiatica extract ameliorates deoxygenation-induced neurological dysfunction in zebrafish larvae

“…Zebrafish have become a crucial model organism for studying hypoxic conditions due to their external fertilization, small size, rapid development, high reproductive output, and transparent larval bodies, facilitating easy observation ( Üstündağ et al ., 2019 ). Under OD conditions, oxygen diffusion from the gills to the blood is impaired, affecting respiratory efficiency ( Pelster, 2021 ).…”

“…Larvae at the age of 3 dpf were followed until they reached 9 dpf for subsequent measurements, in line with the methodologies of larvae aged 3 dpf and were monitored until they reached 9 dpf for measurement ( Avdesh et al ., 2012 ). Larvae aged 3 dpf were observed until they reached 9 dpf for measurement ( Üstündağ et al ., 2019 ). All protocols for handling and care of these laboratory animals were in strict compliance with the established ethical guidelines for laboratory animal welfare.…”