Abstract
Purpose:
Iodate intoxication can lead to a severe damage of the retinal pigment epithelium (RPE). This damage is more pronounced at the posterior pole. This can be seen in animals and in accidental intoxication in humans. It is therefore hypothesized that light amplifies the toxic effect of iodate at the RPE.
Methods:
Adult C57BL/6J wild-type mice were injected with sodium iodate (20 mg/kg body weight) or the equivalent volume of saline solution. The animals were kept either in total darkness or in a 12-h dark/12-h light cycle with exposure to full-spectrum light at illumination levels of 4000-5000 lux. After 20 days the cell count of photoreceptors, morphology and dissemination of damage of RPE were compared between the groups at various areas of the retina (25%, 50% and 75% of the distance between optic disc and ora serrata).
Results:
A significant reduction of photoreceptors was found in both iodate groups compared to the control [25%: 224 ± 1.9 vs. 136 ± 3.2 in darkness (P=0.001) vs. 101 ± 2.3 in light (P<0.001); 50%: 211 ± 0.8 vs. 141 ± 2 in darkness (P<0.001) vs. 106 ± 2.4 in light (P<0.001); 75%: 204 ± 1.6 vs. 128 ± 2.7 in light (P<0.001) vs. 113 ± 1.4 in darkness (P<0.001)]. A difference between both iodate groups was found at the 50% area (P=0.04).
Conclusions:
In our experiments the iodate-induced photoreceptor damage in mice was aggravated by light in certain areas of the retina.
Keywords: 701 retinal pigment epithelium •
670 radiation damage: light/UV •
648 photoreceptors