Biochemical and morphological changes in isolated rat liver mitochondria exposed to ultraviolet light.

Abstract

The correlation between the ultrastructural change of mitochondria following ultraviolet exposure and the functional disorder of respiratory chain was discussed on the isolated mitochondria prepared from rat liver. The considerable swelling of mitochondria after exposure was recognized under an electron transmission microscope and a scanning electron microscope. The addition of ATP to the exposed mitochondria showed the reversion of ultrastructural changes caused by ultraviolet exposure. The exposed mitochondria showed the loss of ability to couple the phosphorylation with the respiration, the decrease of both RCR and ADP/O ratio, the stimulation of state 4 oxygen consumption, the increase of ATPase activity and no effect of ADP to oxygen consumption. In the exposed mitochondria, there was a marked decrease in the component of cytochrome b, c+c1 and falvoprotein on the respiratory chain. Our results suggested that the effects of ultraviolet light on mitochondria may be mediated in part by the oxidation products of lipid constituents.