Metabolic alterations in tissues perfused with decalcifying agents

Abstract

Isolated parenchymal-cell suspensions, prepared from livers and kidneys of adult rats and rabbits after the perfusion of these organs with citrate or EDTA, were compared with tissue slices from un-perfused organs. The isolated cells in each case showed a much lower rate of endogenous respiration in vitro than the corresponding slices, a lower rate of anaerobic glycolysis and a greater increase in respiration on the addition of succinate. They showed no increase in oxygen uptake on the addition of pyruvate or a-oxoglutarate unless incubated in a high-K medium with added ADP. Mitochondria obtained from isolated rat-liver cells and incubated in the presence of a-oxoglutarate respired at the same rate as mitochondria freshly prepared from untreated normal liver. Liver- cell suspensions incubated under the same conditions showed the same initial rate of O2 uptake as equivalent amounts of mitochondrial preparations, but the rate decreased rapidly during continued incubation of the cells. The cells showed a sharp rise in rate of O2 uptake when 2,4-dinitrophenol was added early in the incubation, but not when it was added after 40 min. Tissue slices cut from unperfused rat livers and from livers perfused with Krebs-Ringer phosphate solution showed identical rates of endogenous respiration, identical increases in O2 uptake on the addition of succinate, and identical losses of protein into the incubation medium. Slices from livers perfused with the same solution containing citrate or EDTA showed the same rate of endogenous respiration as the controls, but a greater increase in O2 uptake on addition of succinate, and a greater leakage of protein into the medium. The addition of polyvinylpyrrolidone to the perfusing fluid appeared to diminish these effects. Kidney-cortex slices cut from rat and rabbit kidneys after perfusion with solutions containing EDTA or citrate showed essentially the same rates of endogenous respiration, and the same stimulation of respiration by the addition of succinate, as corresponding controls. The results are interpreted as evidence for a marked alteration of permeability of the cell membrane after treatment with citrate or EDTA, independently of any mechanical damage to the cell. The absence of such changes in slices from perfused kidneys is attributed to the histological organization of the kidney, which may prevent free access of the chelating agent to the renal epithelium.