<b>Histological and immunohistochemical study of the thyroid gland of the broad-snouted caiman (<i>Caiman latirostris</i>)</b> - doi: 10.4025/actascibiolsci.v35i4.18444

Abstract

The broad-snouted caiman, Caiman latirostris, is widely distributed in countries of South America. In Brazil it is considered an endangered species because of natural habitat destruction and illegal hunting. In reptiles, the thyroid gland plays an integral part in ecdysis, reproduction, tail regeneration, growth, endocrine function and metabolism rate. The aim of the present study was to characterize the thyroid gland morphology of C. latirostris, based on histochemical and immunohistochemical techniques. The thyroid glands were fixed in Bouin's fluid and serial cross sections were stained with hematoxylin-eosin, Mallory's trichrome, periodic acid-Schiff (PAS) and Alcian blue (AB pH 1.5 and 2.5). The immunohistochemical technique for 5-HT-IR cells was used. The thyroid gland has a dense irregular connective tissue forms a capsule enveloping the gland. There are several follicular acini of varying size lined by simple cuboidal or columnar epithelium in the thyroid gland. The follicles are connected by interfollicular connective tissue which contains blood vessels. We observed the presence of lymph nodes around the entire gland. There was a positive PAS reaction and negative AB reaction in the colloid. 5-HT-IR cells were detected around the follicle cells. No striking morphological differences were observed between C. latirostris and other domesticated mammals.

The Effect of the Seasons and Sex on the Structure and Activity of the Thyroid Gland of Dromedary Camels

“…In the thyroid of European bison (Bison bonasus), the follicular epithelium is higher in the warm months than in cold months (Sawicki et al, 1992). In general, not only the height of the follicular epithelium or the size of the follicles are affected by the activity of the gland, but the number and texture of colloid material, the presence of blood and desquamated epithelial cell, as well as the staining affinity of the colloid, all are affected thyroid activity (Machado-Santos et al, 2013). In a species known for being poor thermoregulators, like the Iraqi buffalo (Bubalus bubalis), no significant variations were detected in the thyroid gland's histological features between summer and winter (Hussain and Al-Taay, 2009).…”

Microscopic anatomy of the oesophagus in the southern white‐breasted hedgehog (Erinaceus concolor) a histochemical, stereological, and scanning electron microscope study

“…The epithelium of the oesophagus is a stratified squamous type in all mammalian species. But it is reported to be pseudostratified columnar in reptiles (Ahmed et al, 2009;Machado-Santos et al, 2011) and stratified cuboidal in some fishes (Abd El Hafez et al, 2013). The stratified squamous epithelium can be categorized into keratinized or non-keratinized epithelium depending on species-specific feeding habits (Banks, 1993).…”