Objective To investigate the effects of
mifepristone for labor induction of full-term pregnancy on the rat myocardial tissue.
Methods 10 pregnant rats were randomly divided into two groups, control group (n=5) gavaged with 1 ml sesame oil and
experimental group (n=5) with 1 ml sesame oil +mifepristone (11.5±1)mg on the 20th day of pregnancy. 24 h after delivery, myocardial tissues of the mature rats were obtained and prepared for transmission electron microscopic examination. The
mitochondria parameters were analyzed by stereology. Results In comparison with the control group, the myocardial tissue of the experimental group displayed the following morphological changes: Some muscle cells were edematous, mitochondria were markedly swollen with decrease of cristae. In the interstitium, the capillary endothelial cells' cytoplasm were also swollen. In the experimental group, the mean volume and volume density of mitochondria increased obviously, but no significant change in the numerical density. Conclusion Using mifepristone for labor induction of full-term pregnancy can cause hypoxic damage in rat myocardial tissue.