Histomorphometric alterations in aloe vera gel extract treatment in the diabetic rat’s retina

Abstract

The retina is a part of the central nervous system in terms of histological and embryological aspect. It is a thin layer of neural tissue lining the inner eye. This study assessed the histomorphometric changes in the thicknesses of the retina and its layers using light microscope (LM) and retinal photoreceptor cells using transmission electron microscope (TEM) as a consequence of diabetes and effect of aloe vera gel extract in male rats. Thirty Sprague-Dawley matured male rats (175 ± 25 g) in two age groups (12 and 16 weeks) were divided into three main groups as control, diabetic, and diabetic receiving 400 mg/kg aloe vera extract. There were two subgroups in each group. For inducing diabetes, a single dose of streptozotocin (STZ) (50 mg/kg) was injected through IP route. Their blood sugar was measured by a glucometer before STZ administration and 24 h thereafter. At the end, animals were anesthetized with sodium thiopental (40 mg/kg) via IP injection. The retina was collected for tissue processing following dissection of eyes, fixed in 4 glutaraldehyde, postfixed in osmium tetroxide 1 , dehydrated, and then embedded in TAAB resin. Semithin sections (1 μm) were stained with toluidine blue stain and viewed under light microscope. Ten slides were prepared from each animal. Ultrathin sections were prepared, stained, and viewed under TEM. The blood glucose levels and body weight in treated rats were reduced in comparison to diabetic groups. The neural retina thickness and its layers were also different. In the aloe vera-treated group, the thickness of the retina and its layers retained their normal histological structures. In diabetic groups, the vesicular mitochondria and degenerated cristae and dense nucleus were observed in photoreceptor cells. After treatment with aloe vera extract, cristae gained partially their arrangement and chromatin spread. It is concluded that the degenerated retina and the thickness of different layers of diabetic retina could be affected with long-term treatment of aloe vera gel extract. © 2014, Springer-Verlag London.