Mitochondrial Permeability Transition Pore Assay Kit

The mitochondrial permeability transition pore (MPTP) is a non-specific channel composed of the inner and outer mitochondrial membranes, involved in the release of substances within the mitochondria during cell death. The kit uses the fluorescent probe Calcein AM to stain cells. Calcein AM is a non-polar dye that can stain live cells with fluorescence, entering cells through passive transport and accumulating in cytoplasmic components such as mitochondria. Once inside live cells, Calcein AM is catalyzed by esterase to produce Calcein, causing the entire cell to exhibit strong green fluorescence. After treatment with cobalt ions (provided in the kit), Calcein will bind to cobalt ions, leading to fluorescence quenching. However, under normal circumstances the MPTP is not open, so cobalt ions cannot enter the mitochondria, resulting in only the mitochondria displaying green fluorescence. Further treatment with Ionomycin allows calcium ions to enter the cells, causing the MPTP to open, and cobalt ions to enter the mitochondria, leading to the quenching of the green fluorescence of Calcein inside the mitochondria. If there is a sample that can induce partial or complete opening of the MPTP, it will result in a weakening or even disappearance of the green fluorescence in the mitochondria.

Figure 1: The efficiency of this kit for detecting the openness of mitochondrial MPTP