Losartan delays the progression of streptozotocin‐induced diabetic cataracts in albino rats

Abstract

The ocular renin‐angiotensin system has become an interesting target for ocular diseases because it has been implicated in various ocular diseases such as diabetic retinopathy, glaucoma, age‐related macular degeneration, uveitis, and hypertensive cataracts. In the present study, we explored the effect of topically and orally administered losartan (an angiotensin receptor blocker) on streptozotocin‐induced diabetic cataract in albino rats. Topical treatment with losartan modulated neither the blood glucose level nor the polyol content but oral treatment with losartan decreased both. Topical and oral treatment with losartan significantly increased the antioxidants (glutathione, glutathione peroxidase, superoxide dismutase, and catalase), decreased the lipid peroxidant malondialdehyde, and restored soluble protein, and insoluble protein and various ions (Na+, K+, and Ca2+) in the lens; however, topical treatment had a better effect than oral treatment. These findings demonstrate that topical administration of losartan significantly reduces the risk of cataract formation without affecting either the blood glucose level or polyol contents.

Therapeutic effects of various renin angiotensin modulators on hyperglycemia-induced cataract formation in Sprague Dawley rats

“…The doses of RAS modulators were established based upon one patent study and our previous study. 4,34 We carried out pilot study on RAS modulators at four different concentration 0.1% w/v, 0.2% w/v, 0.5% w/v, and 1% w/v for each drugs. Results of pilot studies indicated 0.1% w/v and 0.2% w/v to be the least effective.…”

“…We recently established that topically administered angiotensin receptor blocker (ARB) prevented the progression of streptozotocin (STZ)-induced formation of cataracts. 4 On the basis of our recent study, one may postulate that the local RAS in the eyes may intensify formation of cataracts in hyperglycemic conditions. In addition, the ocular RAS has become a unique pathway for the treatment and the prevention of various eyes related disorders.…”

“…Previously, we established that ARB delayed the cataract formation. 4 Hence, we thought that exploring the comparative effects of renin angiotensin modulators on cataract formation would be worthwhile.…”

Role of the renin–angiotensin system in the development of cataract formation in angiotensin‐II‐induced experimental rats

“…Secondary complications with the eyes may elicit pathophysiological events in eyes' lenses and cause cataract formation, which corroborated the result of our previous studies. [8,15,17] Oxidative stress is a key factor in the generation of cataracts. [35] In this study, the Ang-II control group showed a significant elevation in lenticular oxidative stress as compared with the normal group.…”

“…[ 12,14 ] In addition, various studies have revealed a possible link between the RAS and cataract formation; that is, RAS modulators, angiotensin receptor blockers (ARBs) and angiotensin‐converting enzyme inhibitors have been found to delay cataract formation in different cataract models. [ 7,15–17 ]…”