Abstract of research

CLINICO-BIOCHEMICAL, ULTRASONOGRAPHIC AND HISTOPATHOLOGICAL CHANGES IN EXPERIMENTALLY-INDUCED HYPOTHYROIDISM IN DOGS.

Yousif, H.M.a, Ghanem, M.M.b, Abd El-Raof, Y.M.b, El-Attar, H.M.b

Abstract

Hypothyroidism was induced in dogs by three methods. The first method was drug-induced hypothyroidism by Sulphamethoxazole-Trimethoprime combination. The second method was thyroidectomy-induced hypothyroidism (surgical removal of thyroid gland), and the third method was ligation-induced hypothyroisim (surgical ligation of thyroid arterial blood supply). The most common clinical signs appeared in three groups after induction were lethargy, weight gain, alopecia, and other dermatological changes. The biochemical changes included hypercholesterolemia, hypertriglyceridemia, elevated liver enzymes (AST, ALT), hypocalcaemia, hypophosphatemia, hypernatremia. Ultrasonographic changes of thyroid gland in drug-induced hypothyroidism showed increase in both total and relative thyroid volume with decreased relative echogenicity. In ligationinduced hypothyroidism the total and relative thyroid volume and also the relative echogenicity were decreased. Histo-pathological changes of thyroid gland revealed hyperplasia of glandular epithelium with papillary projection into the lumen and lymphocytic cellular infiltration, and desquamation of lining epithelium in drug-induced hypothyroidism. In ligation-induced hypothyroidism, thyroid follicles were atrophied with hypertrophy of lining epithelium.