Abstract
Purpose. To perform morphometric analysis of retinal structural components in rabbits in experimental diabetes mellitus (DM) in an attempt to digitize possible retinal neurodegenerative changes foe comparison with other species with induced DM.
Material and Methods: Stained hematoxylin and eosin histological sections from 19 eyes of 19 Chinchilla rabbits were retrospectively reviewed. Of the 19 eyes, 11 were from 11 rabbits at 16–17-week diabetes duration, and 4 were from 4 healthy rabbits. Total retinal thickness was measured in micrometers, and thicknesses of the following layers were measured in the neurosensory retina: the photoreceptor layer (PRL), outer nuclear layer (ONL), outer plexiform layer (OPL), inner nuclear layer (INL), inner plexiform layer (IPL), and ganglion cell layer (GCL)/ nerve fiber layer (NFL). The numbers of nuclear rows in both nuclear layers were calculated visually. An eyepiece micrometer was used to perform retinal layer thickness measurements.
Results. Total retinal thickness (mean ± standard error of mean) was 110.6 ± 3.77 µm for healthy animals versus 111.0 ± 2.33 µm for diabetic animals; PRL thickness, 27.8 ± 2.11 µm versus 21.9 ± 1.30 µm; ONL thickness, 28.4 ± 0.97 µm versus 11.0 ±0.60 µm; OPL thickness, 8.1 ± 1.37 µm versus 27.8 ± 0.85 µm; INL thickness, 13.8 ± 0.99 µm versus 6.1 ± 0.61 µm; OPL thickness, 16.0 ± 1.05 µm versus 18.3 ± 0.65 µm; and GCL/NFL thickness, 16.5 ± 1.04 µm versus 25.8 ± 0.64 µm, respectively. The number of nuclear rows in the ONL was 6.94 ± 0.17 for healthy animals versus 1.96 ± 0.10 for diabetic animals. The number of nuclear rows in the INL was 3.03 ± 0.09 for healthy animals versus 1.57 ± 0.05 for diabetic animals. Obviously, the retina of diabetic rabbits showed pronounced signs of neurodegeneration.
Conclusion. Microscopic pictures of retinal sections of and the estimated thicknesses of individual retinal layers and numbers of nuclear rows in the ONL and INL from, diabetic rabbits at 16–17-week diabetes duration indicate that the dithizone-induced diabetes rabbit model used may be considered suitable for histological (hematoxylin and eosin) evaluation of retinal degenerative changes.