Morphological criteria for diagnosis of hypothyroid cardiomyopathy
The work was carried out on experimental material. Thyroidectomy was performed on 73 white male rats sexually mature, weighing 250-300 grams. Operation thyroidectomy was performed under general anesthesia. The duration of the experiment is 60 days. The rats were removed from the experiment on the 7th, 14th, 21st, 28th, 35th and 60th days. As a control, 23 rats were used, which did not undergo thyroidectomy. For histological examination, pieces of the myocardium of the left and right ventricles of the heart were taken. The pieces were fixed in 10 % buffered formalin, then conducted through an alcohol battery, poured into paraffin, and 5 microns thick sections were prepared. Sections were stained with hematoxylin and eosin, picrofuxin according to Van Gison, toluidine blue. The immunohistochemical study was performed by peraksidase- antiperoxidase method using standard diagnostic protocols of the manufacturer. Biomarkersdesmine and muscular-specific actin (SA) were used. In histological study of myocardium in rats, vascular disorders and interstitial edema were revealed. Hydrophobic dystrophy is observed in the cytoplasm of cardiomyocytes, erosion of the pattern, uneven staining is noted. In the stroma of the myocardium, multiple focal lymphocytic infiltrates were found. At the end of the experiment, severe dystrophic and destructive changes develop in the myocardium, multiple foci of plasmolysis, fragmentation of fibers, thinning and atrophy of them, the formation of cavities filled with edematous fluid. In immunohistochemical studies, desminus expression is positive cytoplasmic. By the end of the experiment, desmine expression becomes uneven. Cardiomyocytes react differently. Expression is weakly positive. Expression of SA at the beginning of the experiment is positive uniform. There is a bright diffuse staining. At the end of the experiment, there is a weakly positive expression.