Original scientific paper

Pathological and biochemical studies of experimental hypothyroidism in sheep

Khodadad Mostaghni ; Department of Clinical Sciences, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
Khalil Badiei ; Department of Clinical Sciences, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
Azizollah Khodakaram-Tafti ; Department of Pathobiology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
Ali Bashari Maafi ; Department of Clinical Sciences, School of Veterinary Medicine, Shiraz University, Shiraz, Iran

Abstract

The objective of this experiment was to determine pathological and biochemical changes in hypothyroid sheep. Experiments were carried out using 12 Iranian crossbred sheep aged between 3-3.5 years old and weighing 45-65 kg. The animals were divided into two groups, 4 sheep as control and 8 as the experimental group. Hypothyroidism was induced in experimental animals by giving thiourea 50 mg/kg body mass daily for 4 weeks. Blood samples were taken weekly for T3 and T4 measurements. There was a highly significant decrease (P<0.01) in values of T3 and T4 in experimental animals as compared to the control group. At the end of the experiment all the animals of control and experimental groups were sacrificed and necropsied. Tissue samples
were collected from the thyroid, kidney, liver, skin and spleen and stained by hematoxylin and eosin and sudan 3 and 4. In the experimental group the following changes were observed: the thyroid gland was moderately enlarged and firm in texture and darker in color. Histopathologically, the epithelial lining of the thyroid follicles showed hypertrophy and hyperplasia which projected into the lumen. The lumens of the follicles were empty of
colloid. Kidneys were apparently normal but microscopically showed glomerular lipidosis and tubular changes including mild congestion and lipidosis. The liver was pale, anemic, friable and enlarged. The hepatocytes exhibited fatty change and some inclusion bodies in their nuclei. Moreover, hyperplasia of bile ducts and mononuclear cell infiltration of liver were seen. The skin was mainly normal in the majority of the cases but histologically one case showed hyperkeratosis of the epidermis, associated with excessive keratin formation within the hair follicles. In the spleen, the number and size of macrophages were increased and one case showed some petechial hemorrhages on its surface. The treated ewes showed significant hyperlipidemia (P<0.01) and
hypercholesterolemia (P<0.01). A significant decline (P<0.01) was detected in HDL as well as a significant increase (P<0.01) in LDL serum levels of the treated ewes.

Keywords

sheep; hypothyroidism; thyroid hormones; pathological changes

Hrčak ID:

24193

URI

https://hrcak.srce.hr/24193

Publication date:

9.6.2008.

Article data in other languages: croatian

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