Using FluoZin-3 and fura-2 to monitor acute accumulation of free intracellular Cd2+ in a pancreatic beta cell line

Abstract

AbstractThe understanding of cellular Cd2+accumulation and toxicity is hampered by a lack of fluorescent indicators selective for intracellular free Cd2+([Cd2+]i). In this study, we used depolarized MIN6 mouse pancreatic beta cells as a model for evaluating [Cd2+]idetection with commercially available fluorescent probes, most of which have been traditionally used to visualize [Ca2+]iand [Zn2+]i. We trialed a panel of 12 probes including fura-2, FluoZin-3, Leadmium Green, Rhod-5N, indo-1, Fluo-5N, and others. We found that the [Zn2+]iprobe FluoZin-3 and the traditional [Ca2+]iprobe fura-2 responded most consistently and robustly to [Cd2+]iaccumulation mediated by voltage-gated calcium channels. While selective detection of [Cd2+]iby fura-2 required the omission of Ca2+from extracellular buffers, FluoZin-3 responded to [Cd2+]isimilarly in the presence or absence of extracellular Ca2+. Furthermore, we showed that FluoZin-3 and fura-2 can be used together for simultaneous monitoring of [Ca2+]iand [Cd2+]iin the same cells. None of the other fluorophores tested were effective [Cd2+]idetectors in this model.