Effects of L-Carnitine and Cinnamon Extract Treatment on Lens Crystallins of Rats Fed High Fructose Diet

Problem statement: Rats fed high dietary fructose are documented to f orm an acquired model of insulin resistance; the present study aims to investigate possible changes in lens crystallin s of rats fed high fructose diet and the effects of admi nistration of each exogenous L-Carnitine (CA) and Cinnamon Extract (CE) on protein glycation, oxidati ve stress and redox homeostasis in this rat model. Approach: A total number of 60 male Wister rats of body weig ht 120-160 g were divided into 4 groups of 15 rats each. Group 1 received control di et, while groups 2, 3 and 4: rats received high fructose diet (60g/100 g diet). After 2 weeks from fructose feeding, animals of group 3 were treated with L-carnitine (300 mg g -1 body weight/day i.p.), while animals of group 4 we re treated with cinnamon extract (0.5 mL/rat/day orally). At the en d of experimental period (30 days), serum levels of glucose and insulin were determined. Lenses of each animal were dissected; molecular weights of crystalline, oxidative stress markers, early glycat ion of lens proteins and carbonyl group were assaye d. Results: A significant decline in antioxidants and increase in lipid peroxidation products, protein oxidation and protein glycation were observed in lens samples obtained from fructose-fed rats. Administration of each CA and CE to fructose-fed rats significantly attenu ated oxidative damage and protein glycation and ret urned levels of antioxidants to near those in control gro up. Chromatographic analysis of lens crystalline of rats fed high fructose diet showed diffused peaks, indicatin g crystalline aggregation. Conclusion: The results of the present study indicate that dietary fructose di sturbs lens integrity and administration of L-carni tine or cinnamon extract may safeguard the lens by minimizing the protein aggregation, preventing glycation and oxidative stress in animals fed high fructose diet. L-carnitine has more potent effects than CE in this animal model.