Various LED Wavelengths Affected Myofiber Development and Satellite Cell Proliferation of Chick Embryos via the IGF-1 Signaling Pathway.

An effect of monochromatic light illumination on muscle mass has been discovered in chickens; however, its effect on the development of embryonic muscle remains unclear. Our previous studies demonstrated that monochromatic green light promoted satellite cell proliferation and muscle growth in posthatching broilers. In this study, we investigated the effects and mechanisms of monochromatic light exposure on muscle development in late embryogenesis. Seven hundred and fifty fertile broiler eggs were randomly assigned to blue (B-group), green (G-group), red (R-group), white (W-group) lights or darkness (D-group) throughout the incubation period. The muscle weight and fiber size were highest in the G-group compared to the other groups during embryonic days (E) 17 to E20. The proliferation of satellite cells isolated from the G-group was highest, and in vivo green light remarkably increased the number of proliferating cell nuclear antigen (PCNA)-positive cells in skeletal muscle. Meanwhile, plasma IGF-1 was higher (15.5-16.2%) in the G-group than that in D- and R-groups, and the satellite cells isolated from the G-group had a more sensitive response to IGF-1. These findings demonstrate green monochromatic photobiomodulation promoted the muscle growth and satellite cell proliferation was related to the IGF-1 signaling pathway in late embryogenesis.