Effects of streptozotocin-induced type 1 diabetes mellitus on protein and ion concentrations in ocular tissues of the rat

• Published in: Dubai diabetes and endocrinology journal Vol. 13; no. 3; pp. 154 - 158
• Main Authors: Roy, Koushik, Harris, Frederick, Dennison, Sarah Rachel, Phoenix, David Andrew, Singh, Jaipaul
• Format: Journal Article
• Language: English
• Published: Basel, Switzerland 01.03.2019
• Subjects: Further Section; cations; rat; ocular tissues; retinopathy; protein; diabetes; Type 1
• ISSN: 2673-1797; 1606-7754; 2673-1738; 2073-5944
• DOI: 10.1159/000497584

This study investigated the effects of streptozotocin (STZ)-induced diabetes mellitus (DM) on protein and cation levels in ocular tissues (lenses, cornea, lacrimal glands and retina with sclera) of rats. Diabetic rats and their lacrimal glands weighed significantly less (p < 0.05) than age-matched controls. Diabetic animals also had significantly (p < 0.05) elevated blood glucose and significantly reduced (p < 0.05) plasma insulin compared to controls. Total protein concentrations in the cornea, lens, lacrimal gland and retina with sclera were markedly reduced compared to controls (circa 50%-90%). Diabetic cornea, lenses, lacrimal glands, and retina with sclera contained more Ca2+ (p < 0.05) than age-matched controls (2-3 fold). Levels of Zn2+ were also elevated (p < 0.05) in the cornea and retina with sclera of diabetic rats, as compared to control rats (2-3 fold), but were unaffected in lenses and lacrimal glands. In contrast, levels of Cu2+, Mg2+, Na+ and K+ were significantly reduced (p < 0.05) in all ocular tissues of diabetic rats when compared to control animals (circa 30%-70%). These results show that STZ-induced DM is generally associated with significant physiochemical changes in ocular tissues of rats with changes observed in body weight, blood glucose, and insulin levels and protein and cation concentrations compared to healthy agematched controls. Based on these data, it has been speculated that diabetes may induce changes in ocular tissues that include: higher protein turnover through increased protease activity and changes in Na+ / K+ channel function. It is suggested that these changes may be associated with diabetic retinopathy, diabetic cornea and sight impairment. (Int J Diabetes Metab 13:154-158, 2005)