< Back to Article

Mitochondrial Structure and Function Are Disrupted by Standard Isolation Methods

Figure 3

Quantitative and qualitative alterations of mitochondrial respiration in isolated mitochondria.

(A) Schematic diagram of the relevant mitochondrial components involved in mitochondrial respiration and antioxidant defenses. represent the sequence and site of action of each substrate added to the respirometry assay. Bold italicized items are matrix components which may be partially lost during mitochondrial isolation. (B) Mitochondrial oxygen consumption with sequential substrate addition protocol in both preparations, expressed relative to permeabilized myofibers. Baseline – permeabilized myofibers or isolated mitochondria without substrate; GM – Glutamate-Malate; State 3 GM – GM + ADP; State 3 GMS – State 3 GM + Succinate; TMPD – State 3 GMS + Antimycin A (AA) + TMPD + Ascorbate. (C) Respiratory control ratio (RCR) for both preparations. (D) Mitochondrial respiration ratios calculated for both preparations, representing the relative activity of complexes I, II and IV. Abbreviations: I, II, III, IV, IV – electron transport chain complexes I to IV, and ATP synthase (V); NAD⁺ – nicotinamide adenine nucleotide; NADH – reduced NAD⁺; TCA – tricarboxilic acid cycle; MnSOD – manganese superoxide dismutase; GPx – glutathione peroxidase; TPx – thioredoxin peroxidase. N = 8 animals per group, values are means ± s.e.m. * = p<0.05 ** = p<0.01.

doi: https://doi.org/10.1371/journal.pone.0018317.g003