8. 670 NM red light: protection against retinopathy of prematurity and low developmental weight

Abstract

Retinopathy of prematurity (ROP) is a vasoproliferative disorder that can lead to blindness. Red light irradiation at 670 nm wavelength promotes cellular differentiation, proliferation and wound repair. 670 nm light is believed to stimulate mitochondrial function by increasing cytochrome oxidase efficiency and ATP production. In the retina, 670 nm light protects photoreceptors from the effects of a number of noxious stimuli including toxins, light-induced and oxygen-induced degeneration. Aims To determine whether treatment with 670 nm light would promote normal vessel development in a mouse model of ROP (oxygen induced retinopathy – OIR model) and whether it would affect organ development and growth. Method C57/Bl6j mice were treated as controls. The other groups were OIR mice (75% oxygen, p7–12 days; normoxia p12–17 days) and C57/Bl6j and OIR mice that were treated with 9 J/cm2 of 670 nm light daily from p7–17. At p17 animals were sacrificed and the retinal vasculature visualised by labelling with lectin. Analysis for the presence of neovascularisation and vaso-obliteration was performed using established protocols. Weight and length measurements were recorded daily, and at p17 their organs were harvested. All organs were examined macroscopically and microscopically. Results There was a significant reduction (p Conclusions Exposure to 670 nm red light may be a novel strategy to promote normal vessel development and protect against ROP. 670 nm treatment might also prove useful in assisting pre-term infants increase body weight and reduce lung damage.