The purpose of this study was to establish a developmental toxicity test using common marmoset (Callithrix jacchus) and collect background data.
Twenty pairs of common marmosets born in our institute were used. Pergnant animals were obtained by short-term mating (between 7 and 14 days after delivery). The gestation rate was 43% and the abortion rate was 8%. Pregnancy was diagnosed by palpation of the uterus from the abdominal wall and pregnancy could be diagnosed from the 45th day. Caesarian section was performed on the 110th day of gestation (109-111th day of gestation) and the 100th or 120th day of gestation.
The mean body weight of the fetuses on the 110th day of gestation was 10.2g, the body length 60 mm and the tail length 58 mm. The mean weights of the main organs were 84 mg for the heart, 249 mg for the lungs, and 343 mg for the liver. Growth of the main bones in fetuses on the 100th day of gestation was still comparatively immature. Dead fetuses were observed on the 120th day of gestation, but all of the other fetuses survived and no deformations were found.
The effects of retinoic acid (All-trans retinoic acid, Sigma Chemical Co.) on the fetuses of common marmosets were studied. Retinoic acid was administered at doses of 30 mg and 300 mg/kg/day (N = 2) on days 50 - 52 of gestation, and 50 mg (N = 2) or 100 mg and 300 mg/kg/day (N = 3) on days 50 - 56 of gestation.
Abortions occurred in all marmosets in the 30 mg^- 3 day group, one animal- (50%) in the 50 mg^- 7 day group and two cases (66%) in the 300 mg^- 7 day group, Fetal death was observed in one animal (10%) in the 100 mg^- 7 day group. Skeletal anomalies including temporal anomalies (56%), hypoplastic mandibles (44%), tail bone defects (11%) and limb bone anomalies (11%) were also observed.
It was found that common marmosets showed the same malformations as other primates when administered retinoic acid.