RESUMO
Objective To study the effect of estrogen on myocardial injury in hypothyroidism rats and to reveal the pathology of occurrence and development of the myocardial injury in hypothyroidism rats.Methods The model of hypothyroidism rats was established by feeding propylthiouracil.The pathology of the female group ( n =40 ) and male group ( n =40 ) was observed dynamicly.The presence of myocardial apoptosis cell was demonstrated by the method of terminal deoxynucleotidyl transferase mediated dTUP nick end labeling (TUNEL).And the immunohistochemistry was used to determine the expression of Caspase-3 and Bcl-2 in the myocardial cells.Results The myocardial cell apoptosis appeared in hypothyroidism rats.With the development of the disease,the apoptosis myocardial cell was increased progressively (Female rats group:the numbers of myocardial cell apoptosis at 3,6,8,10,and 12 weeks were 16.40 ± 2.62,29.50 ± 2.67,34.50 ± 3.34,42.70 ±3.24,and 56.00 ± 2.90 respectively,P ＜ 0.05 ; Male rats group:the numbers of myocardial cell apoptosis at 3,6,8,10,and 12 week were 21.60 ± 2.67,35.50 ± 2.94,41.70 ± 2.96,46.70 ± 3.11,and 60.70 ± 3.31respectively,P ＜ 0.05 ),which indicated that estrogen may be related to myocardial cell apoptosis.Conclusion The myocardial cell apoptosis is related with the myocardial injury in hypothyroidism rats.Myocardial cell apoptosis may result in the myocardial injury.The estrogen participates in regulating apoptosis,but its function gradually weakens with the development of the hypothyroidism.