Aim: Tocotrienol (T3) is known to have potent antioxidant properties. Since
oxidative stress plays a major role in the cataract formation, we hypothesized that
T3 delays cataract development. We aimed to investigate effect of T3 eyedrop in
delaying onset and progression of galactose-induced cataract. Methods: 3 weeksold
Sprague-Dawley rats were divided into 8 groups. Group 1 received normal diet
while rest of the groups received 25% galactose diet. Groups 3-8 received one of 6
different doses of microemulsion of T3 ranges from 0.2-0.01% twice daily. Group
2 was similarly treated with vehicle. Pre-treatment was given for 3 weeks and was
continued for 4 weeks after starting the galactose diet. Slit lamp examination was
done biweekly to assess cataract progression. Cataractous changes were graded
from 0-4 according to progression of cortical vacuole formation to nuclear opacity.
Results: At week 1 of galactose diet, groups 3 and 4 had higher percentage of lenses
that progressed to stage 1B compared to group 2 in which progression was less
severe, whereas in groups 6 and 7, 10% and 25% lenses respectively remained in
stage 0. Groups 3 and 4 continued to show more advanced cataract progression
compared to group 2 in the following weeks until end of experimental period.
However, cataract progression was delayed in groups 6-8 during these subsequent
weeks. Conclusion: T3 delayed cataract progression at low doses but enhanced
cataract progression at higher doses.
