[Morphometric study of the influence of hypo and hyperthyroidism on papillar myocytes at left ventricle of rats]

ABSTRACT

Thyroid gland affects many physiologic and metabolic activities .Thyroxine [T4] and its effective form [T3] regulate metabolism of tissues. These hormones affect the heart work with direct or indirect mechanisms. In the present study we investigated the effect of hypo and hyperthyroidism on rat heart. We used female Wistar rats [250-300 gr] in 3 groups [each consisted of 6] Hyperthyroid rats were treated with thyroxine [1 mg/lit water for 20 days] hypothyroid rats were treated with propylthyoacil [PTU] [0.5 gr/lit water] and Control. Finally, histopathological and stereometric evidences were investigated in heart slides. Results showed that in papillar muscle of hyperthyroid rats, there were clear evidences of hypertrophy and increased capillary density. In hypohtyroid rats, however, changes were in opposite to hyperthyroid rats. Results revealed that during changes of hypo and hyperthyroidism, the metabolic changes are in accordance with cardiac hyperthrophy during hyperthyroidism and in opposite direction in hypothyroid rats