Culture of isolated renal tubules: A method of assessing viability of normal and damaged cells

Recovery from acute tubular necrosis (ATN) depends in part upon the survival and proliferation of epithelial cells in the proximal tubule. After i.v. injection of mercuric chloride in rats or rabbits, less than one-seventh of the proximal tubule cells remain viable. However, these cells proliferate and reline the basement membrane to restore the normal cell population in five days. Cell cycle time is only 14hr [1]. Why some cells are able to survive and proliferate in an environment which kills most tubule cells is not clear. It would seem that a change or adaptation has occurred in the proliferating cells, but this change has not been demonstrated or proven experimentally. One hypothesis is that the proliferating cells have reverted to an “embryonic state”. This has also not been documented, though the regenerating kidney has been shown to have increased anaerobic glycolysis and HMP-shunt activity similar to some embryos [2]. To demonstrate differences in growth requirements or viability of normal and regenerating tubule cells, it was decided to remove normal and regenerating tubules from kidney slices with as little damage as possible and place them in controlled tissue culture conditions. Fetal proximal tubules were to be cultured and compared to regenerating tubules. The conditions were chosen to give maximal cell visualization and to be most conducive to culture of epithelial cells [3]. Time lapse photography was chosen as a criterion for viability of cells. This method is more sensitive than all others for in vitro viability [4].