Organ growth and lung maturation in rabbit fetuses.

The rabbit fetus is one of the most commonly used animal models in experimental studies investigating fetal organ development. However, there is no detailed information about normal growth of organs of rabbit fetuses in English language literature. Fetal rabbits were studied in the second half of gestation between 18th and 30th days. Amniotic fluid volume, body mass (BM), lung, heart and liver masses (LM, HM, LiM), lung and thorax volumes (LV, TV) were determined and LM/BM, HM/BM, LiM/BM, TV/BM and LV/TV ratios were calculated. Additionally fetal lungs were evaluated histologically, BM, LM, HM, LiM and LV were increased until 27th gestational day and then remained unchanged. TV was always increased between 18th gestational day and term. The lung maturation was almost completed in the 27th-28th gestational days. Therefore, BM, LM, HM, LiM and LV are the parameters that can be used to evaluate normal fetal growth between 18th and 27th gestational days. TV seems to be the predictive parameter for evaluation of normal fetal growth during the second half of gestation in rabbit fetuses; 20th and 27th days of gestation are more appropriate for experiments to evaluate lung maturation.