Regular articles
GROWTH AND DIFFERENTIATION OF THE FETAL MOUSE PALATE CULTURED IN VITRO : COMPARISON OF IN VITRO DEVELOPMENT OF DAY-12.5 AND DAY 13.5 FETAL PALATES
TSUNEO KOSAZUMA
Institute of Applied Medicine, Hokkaido Radio-isotope Center, Ltd., Ishikari, Hokkaido 061-32, and Department of Hygienic Chemistry, Hoshi University, Ebara, Shinagawa, Tokyo 142, Japan
Regular article :AATEX 3(2):41-45
Abstract
The palatal regions of days-12.5 and -13.5 mouse fetuses were cultivated in a chemically-defined medium, and their in vitro development was compared at intervals during incubation.
After a 24-hr culture of day-12.5 palates, palatal shelves became elevated and grew towards the midline, which was faster than in vivo palatogenesis between day 12.5 and day 13.5 of gestation. After a 48-hour culture of day-12.5 palates, the opposing shelves came into contact and/or fused with each other in 19% of the cases and partially fused in 6% after a 24-hour culture of day-13.5 palates, contact and/or fusion of the shelves occurred in 88% and partial fusion in 6%. After a 72-hour culture of day-12.5 palates, palatal shelves completely fused in 89%; after a 48-hour culture of day-13.5 palates, shelves completely fused in 31%. After a 96-hour culture of day-12.5 palates, the fusion rate was similar to that of the 72-hour culture, suggesting that the rate reached the maximum after 72 hour. By a 72-hour culture of day-13.5 palates, all the shelves completely fused. Although the in vitro development of day-12.5 fetal mouse palates was somewhat slower than in vivo palatal development, the process of palate fusion in vitro simulated the in vivo palatogenetic process. In conclusion, the 72-hour culture of day-12.5 fetal mouse palates may be most suitable for studying normal and abnormal palatogenesis in vitro and for in vitro teratogen screening.
Key words: palatogenesis, mouse fetus, secondary palate, organ culture, in vitro.