THERMOTAXIS OF HUMAN TROPHOBLASTIC CELLS

The objective of this study was to determine whether cultured human tr ophoblasts migrate in response to changes in oxygen tension or tempera ture. Human trophoblastic cells distributed homogenously within indivi dual wells of standard culture plates were subjected to oxygen and the rmal gradients. The redistribution of cells was determined 90 min to 1 8 h after these gradients had been established. Trophoblastic cells di d not migrate in response to gradients of oxygen or carbon dioxide app lied in this manner. In contrast, the cells migrated in response to th ermal gradients of less than 1 degrees C in the direction of the warme r temperature. The response began within minutes, was reversed by a ch ange in the direction of the thermal gradient, and was inhibited at hi gh cell concentrations. Migration was independent of proliferation or protein synthesis, but required microfilament assembly. The capacity o f trophoblasts to migrate in response to small difference of temperatu re within the physiologic range may contribute to the initiation of pl acental development before contact with the maternal circulation has b een established. (C) 1996 W. B. Saunders Company Ltd