Aspirin pretreatment potentiates hyperthermia-induced teratogenesis in the mouse

OBJECTIVE: Our purpose was to investigate the effect of aspirin pretreatment on hyperthermia-induced teratogenesis. The rationale for the study was based on the growing evidence that prostaglandin pathway may be involved in the cellular response to the thermic injury. STUDY DESIGN: On gestation day 8.5 Swiss mice were treated with 0 or 200 mg/kg of aspirin and 1 hour later exposed to a single 10-minute thermostatic bath treatment at 38 degrees C, 41 degrees C, 42 degrees C, or 43 degrees C. On gestation day 18 uterine contents were evaluated for developmental disorders, including prenatal mortality, intrauterine growth restriction, and external, visceral, and skeletal abnormalities. RESULTS: Consistent with expectations, hyperthermia impaired morphogenesis in a dose-related manner. Although aspirin alone did not reveal embryotoxicity, its administration potentiated hyperthermia-induced teratogenesis. A statistically significant interaction (p < 0.05) was observed at 42 degrees C, where the incidence of fetuses per litter with axial skeletal malformations increased from 20.3% to 55.7%. CONCLUSION: A nonteratogenic dose of aspirin enhanced the teratogenic response to hyperthermia. This result fits the hypothesis that prostaglandins may play a protective role in hyperthermia-induced teratogenesis.