Modulating the Development of Renal Tubules Growing in Serum-Free Culture Medium at an Artificial Interstitium

Little information on the structural growth of renal tubules is available. A major problem is the technical limitation of culturing intact differentiated tubules over prolonged periods of time. Consequently, we developed an advanced culture method to follow tubule development. Isolated tissue containing renal progenitor cells was placed in a perfusion culture container at the interphase of an artificial polyester interstitium. Iscove’s modified Dulbecco’s mediumwithout serum or protein supplementation was used for culture, and the culture period was 13 days. Tissue growth was not supported by addition of extracellular matrix proteins. The development of tubules was registered on cryosections labeled with soybean agglu-tinin (SBA) and tissue-specific antibodies. Multiple SBA-labeled tubules were found when aldosterone was added to the culture medium. In contrast, culture without aldosterone supplementation displayed com-pletely disintegrated tissue. The development of tubules depended on the applied aldosterone concentra-tion. The use of 1106 M and 1107 M aldosterone produced numerous tubules, while application of 1108 M to 11010 M led to a continuous decrease and finally a loss of tubule formation. The devel-opment of labeled tubules in aldosterone-treated specimens took an unexpectedly long period of at least 8 days. The morphogenic effect of aldosterone appeared to be mineralocorticoid hormone–specific since spironolactone and canrenoate abolished the development. Finally, dexamethasone induced widely dis-tributed cell clusters instead of tubules