KURDISTAN UNIVERSITY OF MEDICAL SCIENCES, PASDARAN STREET, NO:160, RESEARCH AND EDUCATION CHANCELLORSHIP, SANANDAJ, IRAN
Objective: Glucocorticoid treatment in babies to prevent chronic long disease causes myocardial hypertrophy and increased myocardial protein content. Although these changes are thought to be transient, there is evidence that dexamethasone (DEX) induces permanent myocardial abnormalities as well. In this study, we investigated the ultrastructural changes of cardiomyocytes during the early period of DEX treatment.
Methods: Pup rats (age: 5 days, number: 24) were treated with intraperitoneal injection of DEX at doses of 0.5, 0.3 and 0.1mg/kg). Control pups were treated with saline. At 1, 3 and 7 days after injection, the rats were killed. The anatomical parameters were body weight (BW) and heart weight (HW).
Results: Our data showed a significant decrease of body weight and heart weight in the 3 and 7-day experimental groups after the last injection. Histological study showed the presence of condensed cardiocytes. Ultrastructural studies showed evidence of degenerative changes in mitochondria and myofibrils and chromatin clumping after the 1st day of DEX injection. In the 3 and 7-day experimental groups, these changes were more serious, and chromatin condensation of cardiomyocytes occurred.
Conclusion: Our study showed that neonatal DEX treatment in rat pups causes a decrease in body weight and heart weight during the early period of injection. Histological studies revealed degenerative changes of cardiomyocytes in the experimental pup rats. Ultrastructural studies showed that the type of cell death may be apoptosis.