Abstract
Purpose: :
To determine the protective effect (PF) of oral supplementation with vitamin-E on UVR-induced cataract.
Methods: :
Altogether, 40 albino Sprague Dawley rats were randomly divided into one group of 20 animals that was orally supplemented with vitamin-E, daily for 4 weeks prior to exposure to UVR while the other twenty rats were breaded without supplementation on the same diet and drinking water. After 4 weeks of feeding, each group was subdivided into 5 subgroups of 4 rats. Each rat received a unilateral exposure to UVR, the dose depending on the subgroup belonging. The sub-group doses of UVR were; 0.0, 2.6, 3.7, 4.5 or 5.2 kJ/m2, respectively, (exposure time 15 min). At 1 week after exposure to UVR, the rat was sacrificed and the lenses were extracted, The intensity of forward light scattering was measured and the macroscopic structure was digitally imaged under dark field illumination, and incident illumination against a grid. The threshold dose for UVR-induced cataract was estimated as MTD2.3:16 for each of the groups. The protection factor (PF) was estimated as the ratio of threshold dose between the group that was supplemented and the group without supplementation.
Results: :
The UVR-exposed lenses in the vitamin-E fed groups developed superficial and slight equatorial cataract, whereas lenses in the control group developed cortical and dense equatorial opacities. Forward light scattering in lenses from the vitamin-E supplemented rats was overall lower than in lenses from the control group. The threshold dose for UVR-300 nm induced cataract was 3.02 and 2.66 kJ/m2 for vitamin-E supplemented and not supplemented rats, respectively, resulting in a protection factor of 1.14.
Conclusions: :
Oral Supplementation with vitamin E makes the albino Sprague Dawley rat 14 % less sensitive to early onset UVR-300 nm induced cataract, indicating that vitamin E is effective for prevention of in vivo oxidative stress induced cataract.
Keywords: cataract • radiation damage: light/UV • antioxidants