CONFOCAL AND CONVENTIONAL IMMUNOFLUORESCENCE AND ULTRASTRUCTURAL-LOCALIZATION OF INTRACELLULAR STRENGTH-GIVING COMPONENTS OF HUMAN AMNIOCHORION

Key cytoskeletal polypeptides of human fetal membranes have been local ised at subcellular level using confocal and conventional indirect imm unofluorescence microscopy. Correlation with electron microscope data has allowed us to examine how cellular compartments of this multilamin ar tissue maintain their mechanical integrity until the time of membra ne rupture at parturition. Evidence is presented for myofibroblastic c haracteristics of cells in both the fibroblast and reticular layers wh ich may therefore have tension-generating, position-adjustment and wou nd-healing roles in the amniochorion. Desmin and vimentin are coexpres sed in these cells, but a small localised population of cells in the f ibroblast layer contains vimentin alone. An interaction of cytokeratin filaments with nuclei and desmosomes of amniotic epithelium in vivo i s demonstrated, indicating that nuclei of cells of ectodermal origin a re integrated into a mechanical structure extending throughout the tis sue as a whole. Cells of the basal 1 or 2 layers of trophoblast have b een shown to have a more extensive and better integrated cytoskeletal organisation than those overlying and forming the boundary with decidu a. Structures within the trophoblast, identified previously as degener ate villi, contain cells with intermediate filaments with similar immu nofluorescence properties to those of the neighbouring reticular layer and thus may represent papillae that prevent shearing at this interfa ce.