Tehran University Medical Journal

Background: Aspirin is the drug of the century, and is a multifunctional drug and one of the most prescribed drugs in the world. Aspirin is a safe drug at low doses but also it has life-threatening side effects when administered at high doses. This study investi-gates the effects of aspirin on renal cortical and medullary tissue in rat embryos.
Methods: In this study, 30 pregnant female rats were randomly divided into 6 groups. Control group with no intervention, sham group received 2 ml distilled water (as a sol-vent of aspirin) received from days 8 to 20 of pregnancy, and four experimental groups received different doses of 75, 100, 200 and 300 mg/kg of aspirin by gavage. Pregnant rats were sacrificed on the twenty days of pregnancy and the fetuses were removed. Weight of the fetuses and placenta and Crown-Rump length were measured. Fetal kid-neys were fixed in formalin processed, sectioned and stained with Hematoxylin- Eosin. Thickness of renal cortical and medullary tissue by using a Motic hardware and soft-ware system were measured and recorded. A significance level of 0.05 was predeter-mined for all statistical analyses.
Results: No apparent fetal anomalies were observed in experimental groups. In addi-tion, no significant differences were shown in the mean of fetal weight, placental weight, mean of Crown-Rump length in experimental groups 75, 200 and 300 mg/kg compared to control and sham groups. Mean fetal and placental weight in experimental group 100 significantly increased compared to control and sham groups. Mean ratio of renal cortex to renal medulla in experimental group 75, 100 and 300 were significantly decreased compared to control and sham groups (respectively P= 0.03, P= 0.013, P= 0.03).
Conclusion: It seems that maternal use of aspirin during pregnancy can not cause fetal abnormalities. However, it can cause some changes in renal cortical and medullary tis-sue of rat embryos.