Sn-protoporphyrin plus photoirradiation induces lipid peroxidation in vivo and in vitro in nonjaundiced Gunn rats.

Lipid peroxidation induced by Sn-protoporphyrin (SnPP) plus photoirradiation was investigated in vivo and in vitro using nonjaundiced Gunn rats. Membrane lipids from young adult rat brain were peroxidized by SnPP plus photoirradiation depending on the SnPP concentration and photoirradiance. Similarly, coadministration of SnPP and photoirradiation to suckling rats increased lipid peroxides in the whole blood and was found lethal. The influence of the wavelength distribution of light sources was also examined by using blue-white and green fluorescent lights. The photodynamic effect by green light irradiation whose energy distribution had no overlap with the Soret band of SnPP was about half of that produced by blue-white light with regard to the membrane peroxidation and the lethal effect on neonatal rats. We therefore conclude that the combination of SnPP and photoirradiation is a potentially hazardous treatment of neonatal jaundice.