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Abstract #48763 Published in IGR 14-1

Diabetes mellitus affects biomechanical properties of the optic nerve head in the rat

Terai N; Spoerl E; Haustein M; Hornykewycz K; Haentzschel J; Pillunat LE
Ophthalmic Research 2012; 47: 189-194


BACKGROUND: To investigate the effect of diabetes on the biomechanical behavior of the optic nerve head (ONH) and the peripapillary sclera (ppSc) in streptozocine-induced diabetic rats. METHODS: Diabetes mellitus was induced in 20 Wistar rats using streptozocine. Twenty-five nondiabetic rats served as controls. Eyes were enucleated after 12 weeks and 2 strips of one eye were prepared containing ONH or ppSc. The stress-strain relation was measured in the stress range of 0.05-10 MPa using a biomaterial tester. RESULTS: At 5% strain the stress of the ONH in diabetic rats was 897 ± 295 kPa and in the control group it was 671 ± 246 kPa; there was a significant difference between both groups (p = 0.011). The stress of the diabetic ppSc (574 ± 185 kPa) increased compared to that of the nondiabetic ppSc (477 ± 171 kPa), but this did not reach statistical significance (p = 0.174). The calculated tangent modulus at 5% strain was 11.79 MPa in the diabetic ONH and 8.77 MPa in the nondiabetic ONH; there was a significant difference between both groups (p = 0.006). The calculated tangent modulus at 5% strain was 7.17 MPa in the diabetic ppSc and 6.12 MPa in the nondiabetic ppSc, without a statistically significant difference (p = 0.09). CONCLUSION: In contrast to the ppSc, the ONH of diabetic rats showed a significant increase in stiffness compared to nondiabetic rats, which might be explained by nonenzymatic collagen cross-linking mediated by advanced glycation end products due to high blood glucose levels in diabetes. Further studies are needed to investigate if these biomechanical changes represent a detrimental risk factor for intraocular pressure regulation in diabetic glaucoma patients.

Department of Ophthalmology, Carl Gustav Carus University Hospital, Dresden, Germany.

Full article

Classification:

5.1 Rodent (Part of: 5 Experimental glaucoma; animal models)
2.14 Optic disc (Part of: 2 Anatomical structures in glaucoma)
9.4.15 Glaucoma in relation to systemic disease (Part of: 9 Clinical forms of glaucomas > 9.4 Glaucomas associated with other ocular and systemic disorders)



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