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R.K. Zoltoski, L.A. Novak, D. Garland, J.R. Kuszak; Correlative Structure/Function Analysis of Sutures in Insulin-Treated Diabetic Rat Lenses . Invest. Ophthalmol. Vis. Sci. 2003;44(13):3478.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: We have previously shown that induction of diabetes compromises lens sutural anatomy with a concomitant degradation in optical quality. The purpose of this study was to determine if insulin treatment would restore and maintain lens sutural integrity and optics. Methods: Diabetes was induced in rats (n = 40) by a single tail vein injection of streptozotocin. Age-matched rats (n=20) were used as controls. Diabetic rats (blood glucose>250 mg/dL) were assigned to one of four groups:4 weeks untreated diabetics, 2 weeks untreated diabetics /2 weeks insulin treated (15units/kg), 6 week untreated diabetics, and 2 weeks untreated diabetics/4 weeks insulin treated. Lens optical quality (avg, back vertex distance [BVD] and BVD variability [BVDV, spherical aberration or sharpness of focus]) was quantified by low power helium neon laser scan analysis. Lens structure was assessed by light and scanning electron microscopy. Results: At both 4 and 6 weeks, diabetic rats had lenses with significantly different avg. BVD (2.463±0.285) and BVDV (0.467±0.072) than lenses from age-matched controls (3.146±0.234 and 0.226±0.011). Untreated diabetic rats had cloudy lenses with markedly irregular Y sutures (anterior sutures had enlarged and upturned fiber ends forming an opaque plaque while posterior sutures had multiple major sub-branches). Diabetic rats insulin treated for 2 weeks had no appreciable change in avg. BVD (2.695±0.156), but BVDV was comparable to age-matched controls (0.265±0.020). After 4 weeks of insulin treatment, both avg. BVD (2.947±0.125) and BVDV (0.298±0.014) were significantly different than diabetics and comparable to age-matched controls. Lenses from 2 week insulin treated diabetics were clear though the anterior suture still had enlarged and upturned fiber ends; however, the posterior sutures of these lenses had only minor sub-branches. After 4 weeks of insulin treatment, all lenses from diabetic rats were clear. The majority of these lenses had typical, posterior (inverted Y; 90%) and anterior (upright Y; 70%) sutures. Careful dissection confirmed that the Y sutures of 4 week insulin treated lenses extended beneath the level of new fiber growth. Conclusions: Diabetes induces a rearrangement of both anterior and posterior lens sutures. This structural alteration degrades optical quality. However, treatment with insulin restores lens sutural anatomy and optical integrity. This finding shows that lens sutures have plasticity, the capability of being molded, in response to localized changes.
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