THE EFFECTS OF ENDOTOXIN ON OXYGEN-CONSUMPTION OF VARIOUS CELL-TYPES IN-VITRO - AN EPR OXIMETRY STUDY

We have studied the effects of bacterial endotoxin on the oxygen consu mption of a variety of target cells, and found that the rate of utiliz ation of oxygen by treated cells was decreased in a time- and dose-dep endent manner. Precise EPR measurement of oxygen concentrations enable d us to demonstrate that this effect was linked to mitochondrial dysfu nction and was particular to each cell type. Such detailed knowledge o n oxygen utilization by viable whole cells and the varied effects of e ndotoxin are as yet undocumented. Oxygen consumption was shown to decr ease quite markedly in CHO cells and kidney cells from the cortex regi on. Cells from the kidney medulla region had lower baseline consumptio n and were stimulated to increased levers of oxygen consumption on add ition of similar doses of endotoxin. Macrophages exhibited a dual resp onse in that in addition to inhibiting mitochondrial oxygen consumptio n, endotoxin pretreatment primed these cells to exhibit an enhanced ox idative burst on stimulation with Zymosan. These results show that end otoxin has a direct effect on normal cellular oxygen consumption and i s an important parameter that must be considered when following the ea rly effects on cells and tissues during the septic syndrome.