Lipid hydroperoxide formation in the retina: correlation with retinal degeneration and light damage in a rat model of Smith-Lemli-Opitz syndrome

The Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive disease presenting with multiple congenital anomalies, caused by a defect in cholesterol biosynthesis that results in abnormally elevated levels of 7-dehydrocholesterol (7DHC). Progressive retinal degeneration has been demonstrated in a rat model of SLOS, which is markedly exacerbated by intense light, far more so than occurs in normal albino rats under the same conditions. Herein, we demonstrate that, by six postnatal weeks, retinas in the SLOS rat model contain levels of lipid hydroperoxides (LPOs) comparable to those found in light-damaged albino rats (twice the normal steady-state levels), and that intense light exposure results in a three-fold elevation of LPOs with concomitant severe retinal degeneration. These results suggest a correlation between retinal degeneration and LPO levels. We propose that the presence of 7DHC in the SLOS rat retina potentiates LPO formation, and promotes the observed hypersensitivity to light-induced retinal degeneration.