Occurrence and fate of fetal lumbar rib induced by Scutellariae radix in rats

Abstract

This study was conducted to evaluate the occurrence and fate of fetal lumbar rib induced by Scutellariae radix (SR) in rats. Water extracts of SR were orally administered to pregnant rats from day 7 to day 17 of gestation at a dose of 186 mg/kg/day, equivalent to 25 g/kg of starting material, representing a 100-fold increase over typical human intake level. The incidence of fetal lumbar rib in the SR-treated group was increased on gestational day 20 and then decreased on postnatal day 50. The weight of fetuses in the SR-treated group tended to be less than that in the control group. Alkaline phosphatase in SR-treated dams was increased on gestational day 20, but was decreased on postnatal day 50. There were no significant differences between the vehicle control and SR-treated groups in maternal body weight, embryological, histopathological, hematological, and serum biochemical changes. The present data suggest that the appearance of lumbar rib induced by SR is a transient fetal variation rather than teratogenicity or maternal toxicity.