AMINOGLYCOSIDE-INDUCED INCREASE OF INTRACELLULAR CALCIUM IN LLC-PK1 CELLS DUE TO AN ARTIFACT CAUSED BY TRYPSIN AND EDTA

Dietary calcium supplements attenuate experimental aminoglycoside neph rotoxicity. In cultured renal tubular cells, intracellular calcium lev els have been reported to rise with aminoglycoside addition to the cul ture medium. In experiments designed to verify the in vitro influence of calcium on cultured kidney cells, we detected an unexpected artifac t. When we resuspended cultured LLC-PK1 cells with trypsin and EDTA to measure intracellular calcium levels, our results correlated well wit h previously reported values. However, we saw no increase in intracell ular calcium levels when we measured them by digital imaging video mic roscopy unless trypsin-EDTA exposure preceded aminoglycoside exposure. This apparent artifact should be considered in any study of the effec ts of various agents on intracellular calcium levels.