The morphology of mesangial cells cultured at high density and in collagengels

Primary mesangial cells (rat) from monolayer cultures of the 6th to 12th pa ssage and permanent SV40 Mes13 cells were grown at high density in organoid culture at the medium/air interphase. After adaptation to the in vitro con ditions, both mesangial cell types developed after 7 days a synthesis appar atus (endoplasmic reticulum, Golgi apparatus) and produced matrix which con sisted of Lamina densa-like material, collagenous fibrils and filaments. Un specific contacts, gap junctions and adhesion belts could be demonstrated i n the contact areas. Additionally, some cells exhibited thick bundles of ac tin filaments. A close resemblance of the mesangial cells in high density c ulture to those in vivo can, therefore, be stated. Hence, they differentiat ed with regard to their matrix formation, contraction and contact behaviour and can therefore be used for experimental studies within a short culture period of 7 days. Cell aggregates in monolayer culture and in cultures in c ollagen gels had not differentiated at this stage.