Phototherapy with blue and green mixed-light is as effective against unconjugated jaundice as blue light and reduces oxidative stress in the Gunn rat model

•Young Gunn rat models of unconjugated jaundice underwent blue and/or green light phototherapy.•Blue and green mixed and blue phototherapy are equally effective against unconjugated jaundice.•Blue and green mixed phototherapy attenuates irradiation-induced oxidative stress.

ObjectivePhototherapy using blue light-emitting diodes (LED) is effective against neonatal jaundice. However, green light phototherapy also reduces unconjugated jaundice. We aimed to determine whether mixed blue and green light can relieve jaundice with minimal oxidative stress as effectively as either blue or green light alone in a rat model.MethodsGunn rats were exposed to phototherapy with blue (420-520 nm), filtered blue (FB; 440-520 nm without < 440-nm wavelengths, FB50 (half the irradiance of filtered blue), mixed (filtered 50% blue and 50% green), and green (490-590 nm) LED irradiation for 24 h. The effects of phototherapy are expressed as ratios of serum total (TB) and unbound (UB) bilirubin before and after exposure to each LED. Urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) was measured by HPLC before and after exposure to each LED to determine photo-oxidative stress.ResultsValues < 1.00 indicate effective phototherapy. The ratios of TB and UB were decreased to 0.85, 0.89, 1.07, 0.90, and 1.04, and 0.85, 0.94, 0.93, 0.89, and 1.09 after exposure to blue, filtered blue, FB50, and filtered blue mixed with green LED, respectively. In contrast, urinary 8-OHdG increased to 2.03, 1.25, 0.96, 1.36, 1.31, and 1.23 after exposure to blue, filtered blue, FB50, mixed, green LED, and control, indicating side-effects (> 1.00), respectively.ConclusionsBlue plus green phototherapy is as effective as blue phototherapy and it attenuates irradiation-induced oxidative stress.Practice implicationsCombined blue and green spectra might be effective against neonatal hyperbilirubinemia.