Fig. 2. Electron microscopic views of isolated mitochondria (sham 1 group). (A ) Electron microscopy of heart mitochondria processed after preincubation in buffer C for 90 s, which showed the integrity and purify of mitochondrial fraction before Ca²⁺-induced mitochondrial permeability transition pore opening. (B ) After Ca²⁺-induced mitochondrial permeability transition pore opening, almost the whole population of the heart mitochondria show massive swelling, with disrupted cristae and damaged matrix.