Characterization of Eye and Adnexal Tissues in Dogs and Wolves: A Histological and Lectin-Histochemical Approach

This study explores the ocular anatomy and glandular components of domestic dogs compared to their ancestor, the wolf, with the aim of identifying evolutionary changes due to domestication and their implications for ocular pathologies. Utilizing histological and histochemical techniques, including hematoxylin-eosin, PAS, Alcian Blue, and lectins, this research conducts a detailed analysis of the canine and wolf ocular systems, particularly focusing on the eyelids, tarsal glands, and conjunctival tissues. Results indicate significant histological differences between the two species, particularly in the thickness and secretion levels of the conjunctival epithelia and the structure of the tarsal glands. Dogs exhibit a thicker epithelium with greater PAS and Alcian Blue positive secretion, suggesting enhanced ocular protection and lubrication adapted to domestic environments. Conversely, wolves display more concentrated glandular secretions and a predominance of acidic mucopolysaccharides, aligning with their adaptation to natural habitats. This study also highlights the translational value of dogs as models for human ocular diseases, given their anatomical and physiological similarities with humans. Such comparisons are essential as they provide insights that can lead to advancements in medical research and clinical applications, especially in the development of treatments for ocular surface disorders.