Banca de QUALIFICAÇÃO: TACIANA PONTES SPINELLI

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : TACIANA PONTES SPINELLI
DATE: 14/02/2022
TIME: 16:00
LOCAL: Videoconferência
TITLE:

HISTOLOGICAL AND HISTOCHEMICAL STUDY OF THE OCULAR SURFACE OF THE SLOTH ( Bradypus variegatus Schinz, 1825

KEY WORDS:

Sloth, Ocular surface, cornea, conjunctiva, lacrimal gland, hardenian.

PAGES: 42
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUBÁREA: Clínica e Cirurgia Animal
SUMMARY:

ABSTRACT

Introduction: Sloths (Bradypus Variegatus) are commonly found in Brazil and although this species is not endangered, it is directly or indirectly affected by human action, for example: car accidents with collisions, deforestation, hunting for consumption of exotic meat and pesticide poisoning occur frequently. The species is more vulnerable due to its behavior and physiological characteristics, such as slow movement. They use camouflage as their main defense mechanism. Several studies on ecology, reproduction and nutritional aspects of wild animals have already been published, however, most anatomical characteristics are described in a generalist way or remain unknown. Veterinary ophthalmology is an expanding field and research in comparative ophthalmology produces a range area of knowledge that allows the understanding of different evolutionary processes among species. The ocular surface is of vital importance for vision, being in direct contact with the environment, it is vulnerable to dryness, injuries and pathogens and therefore has a complex mechanism for maintaining its homeostasis. It is composed of the conjunctiva and cornea, which, together with elements such as the lacrimal gland, lacrimal drainage apparatus and eyelids, maintain a healthy ocular surface. Sloths (Bradypus variegatus) may be affected by several ocular diseases, such as occurs with humans, due to different etiologies, thus the importance of characterizing the normal tissues of the ocular surface in these animals since studies on the sloth ocular anatomy and physiology are still scarce. Material and methods: For the development of the histomorphometric study of the ocular surface, eyes were collected from animals sent to the CETAS that died for reasons unrelated to this research. The eyes were fixed in Davidson's medium and sent to the Experimental Ophthalmology Laboratory of the Universidade Federal Rural de Pernambuco and processed for inclusion in paraplast blocks, cut to a thickness of 5μm with the aid of a rotary microtome (Leica, 181 RM2125RT, Germany), placed on glass slides and identified according to the standardized technique of the Experimental Ophthalmology Laboratory of UFRPE (LOE-UFRPE) and stained by the Hematoxylin-Eosin (HE) technique, and Schiff's Periodic Acid (PAS), tricomic masson, and then submitted to evaluation by light microscopy. For histometry, they were photographed and processed with the aid of the WCIF ImageJ® computer program.  The present study aimed to characterize the normal anatomy and physiology of the ocular surface of this species. Results: Anatomical, histological, and histochemical characteristicas of the lacrimal gland, the superficial and profound glands of the third eyelid, palpebral glands, cornea and limbus of the Bradypus variegatus were described. Structural differences were not observed between males and females.  Histologic examination revealed tarsus, tarsal glands and cilia were not present.  Instead, well-developed sebaceous glands associated with accessory hairs along the palpebrae were present. The inner face of the eyelids is lined with the palpebral conjunctiva, which consists of a thin layer of loose connective tissue with a stratified epithelium. Mixed-secreting accessory lacrimal glands were noted in the deep stroma of both palpebrae. The lacrimal gland was situated in the dorsolateral angle of the orbit between the dorsal rectus and the lateral rectus muscles. Histologically, the gland is a tubuloalveolar type. The third eyelid protrudes from the medial canthus over the anterior surface of the globe, its cartilage resembles an anchor in shape. The stroma of the nictitans consists of loose to dense connective tissue that supports glandular and lymphoid tissue. Histological and histochemical examination revealed a superficial and a deep (hardenian) glandular tissue. The deep gland is large and situated in the anteroventral region of the orbit. It is a compound branched, tubulo-alveolar, with a single layer or columnar cells. The cornea is elliptical in shape, with a horizontal diameter greater than the vertical. The anterior epithelium consists of a single cell layer of basal cells, which are columnar in shape and lie on a thin basement membrane; two three layers of polyhedral cells; and three layers of nonkeratinized squamous cells. Basmet membrane is absent. Conclusion: The sloth´s (Bradypus variegatus) do not have tarsus, meibonian glands and cilia. Its lacrimal glandular system is formed by the main lacrimal gland, superficial and deep gland (hardenian gland) of the third eyelid. The eyelids has accessory lacrimal glands. The cornea bowman's membrane is not present and vessels were observed in corneal superficial stroma.

BANKING MEMBERS:
Presidente - 383965 - JOAQUIM EVENCIO NETO
Interno - 385059 - FABRICIO BEZERRA DE SA
Interno - 1929164 - FRANCISCO DE ASSIS LEITE SOUZA