Histopathological Analysis of The Eye And Optic Nerve Structure In The Blind Mole Rat

Abstract

Objective: Blind mole rats (Nannospalax xanthodon Nehring, 1898) are subterranean mammals that are well-known for their high tolerance to hypoxia and resistance to cancer. Due to their unusual habitat, these animals have developed several adaptations during their evolution. Therefore, this study aimed to identify possible structural differences in Nannospalax visual system in comparison to other mammals that might have arisen as a result of adaptation to underground life. Method: Six blind mole rats were used in the study. No procedure was performed on the rats. After the animals were anesthetized with ether, their eyes and optic nerves were removed. For this purpose, pseudo-eyes and optic nerves were harvested and fixed in 10% formaldehyde for a week. Tissues were embedded into paraffin and blocked via routine histological procedures. Five micrometer sections in thickness were taken and stained with Hematoxylin & Eosin (H&E) and Cresyl Violet. Results: Histopathological analysis of the eye revealed the presence of cornea, retina, sclera, iris, zonula adherens, lacrimal gland and ducts, fatty tissue, muscle layer and the vascular structures. No pathology was observed of optic nerve. Conclusions: We found that the visual system of N. xanthodon share some similarities with other blind mole rat species from Israel, while some histological properties were defined by our study for the first time in the literature.