Figure 5.

MESMER assay yields comparable readouts to ICP-MS and is Mn-specific. Murine striatal neuron lineage STHdh Q7 cells were exposed to 50 μm Mn in DMEM for 2 h before being washed in PBS. Samples were subjected to MESMER, ICP-MS, or both (A). For comparison, some cells were not exposed to any extracellular Mn in DMEM, and they received MESM or vehicle prior to sample preparation for ICP-MS (B). Data were normalized to protein via a BCA assay of the samples. A one-way ANOVA with Tukey's multiple comparison tests revealed a significant difference between the samples that were extracted with MESMER prior to ICP-MS compared with those samples that were just extracted with ICP-MS (*, p < 0.05). These samples extracted with MESMER prior to ICP-MS were also significantly different from samples that were just extracted with MESMER alone (**, p < 0.01). Importantly, there was no significant difference between the samples that were measured by MESMER alone or ICP-MS alone (n.s.). For the cells that received no Mn treatment in DMEM (B), there was a significant decrease of extracted Mn in those treated with MESM prior to ICP-MS, compared with those treated with vehicle as measured by a two-tailed t test (*, p < 0.05). ICP-MS for other divalents was analyzed in the samples that had Mn pre-exposed prior to extraction (C) or with Mn pre-exposure (D). There was a significant difference in Ca and Cu in C as measured by Student's two-tailed t test (*, p < 0.05; **, p < 0.01).