The effect of tanshinone IIA on the cardiovascular system in ovine fetus in utero.

This was the first study to determine the effect of tanshinone IIA (an active ingredient in herb Danshen) on fetuses in utero under unstressed condition. Tanshinone IIA or 0.9% NaCl as control was intravenously (i.v.) administrated into pregnant ewes. Both maternal and fetal blood were analyzed for PO(2), PCO(2), SO(2)%, hemoglobin, hemotecrit, glucose, lactic acid, Na(+), K(+), and Cl(-) concentrations. Maternal and fetal heart functions were assessed by examining cardiac enzymes and cardiovascular responses. The results showed that tanshinone IIA did not alter the blood values in ewes and fetuses. Cardiac enzyme activities related to the heart remained unchanged. In cardiovascular experiments, no alternation in maternal blood pressure by tanshinone IIA was observed. However, fetal systolic pressure was slightly and significantly increased following i.v. tanshinone IIA into the mothers, while fetal diastolic pressure, mean arterial pressure, and heart rate were not changed. The results demonstrated that tanshinone IIA used during the last third of gestation did not cause the biochemical changes related to cardiac functions in both maternal and fetal sheep. Fetal oxygen metabolism remained stable in utero, providing new information for clinical use of the herb in pregnancy. That tanshinone IIA increased fetal systolic pressure may open new opportunities to study the herb in fetal medicine.