الملخص

This experiment was designed to identify indicators of oxidative stress and histological changes in the aortic wall of male albino rats with hyperthyroidism. The increasing prevalence of hyperthyroidism worldwide, and its direct association with higher morbidity and mortality rates when left untreated, has made it a highly important focus of histological and pathological studies. twelve adult male white rats, were used and divided into a control group, which had free access to food and water, and an experimental group, which was given 1.5 mg/kg of body weight levothyroxine (L-T4) orally. The experiment lasted 30 days, after which the animals were sacrificed, blood was drawn to examine indicators of oxidative stress, the aortas was also excised and prepared for examination There is a decrease in the concentration of antioxidants (SOD, GSH,CAT) and an increase in the level of (MDA), as well as an increase in thyroid hormones (T3,T4) and a decrease in (TSH) hormone. There are clear histological changes in the layers of the aortic wall in the groups affected by hyperthyroidism, The most important changes are an increase in the thickness of the arterial wall, degeneration of smooth muscle cells, and enlargement of the nuclei in the case of routine staining. However, the characteristic changes in the case of Masson's trichrome staining are an increase in the deposition of collagen fibers in the middle and outer tunica.