Increase ofIntracellular Calcium in LLC-PK1Cells DuetoanArtifact Caused by Trypsin andEDTA

Dietary calcium supplements attenuate experimental aminoglycoside nephrotoxicity. Incultured renal tubular cells, intracellular calcium levels havebeenreported torise withaminoglycoside addition totheculture medium.Inexperiments designed toverify theinvitro influence ofcalcium oncultured kidney cells, we detected anunexpected artifact. Whenweresuspended cultured LLC-PK1cells withtrypsin andEDTAto measure intracellular calcium levels, ourresults correlated well withpreviously reported values. However, we sawnoincrease inintracellular calcium levels whenwemeasured thembydigital imaging video microscopy unless trypsin-EDTA exposure preceded aminoglycoside exposure. Thisapparent artifact should beconsidered inanystudy oftheeffects ofvarious agents onintracellular calcium levels.

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