Figure 6).

Doxorubicin (DOXO) treatment alters the mitochondrial oxygen consumption profile of rat heart tissue. A A representative oxygen flux experiment using saponin-permeabilized cardiac tissue from a control animal that was used to generate a normal response curve after administration of the substrates that increase the consumption of oxygen (pyruvate/malate/glutamate [PMG], ADP and succinate [Succ] and the uncoupling agent FCCP) followed by inhibitors that reduce oxygen consumption (rotenone [rot] and azide [NaN₃]). B The bars represent the mean oxygen consumption that was measured in the control, low- and high-dose groups after each intervention. Data presented as mean ± SEM of three animals. Compared with controls, the low- and high-dose groups displayed a statistically insignificant reduction in the absolute values of oxygen consumption. C The graph depicts the change (Δ) in oxygen consumption at the rate of maximal respiration when using FCCP followed by rotenone inhibition of complex I. Both treatments induce a decrease in complex I activity in the DOXO groups compared with the control group. Fibres were used at 1 mg/mL to 5 mg/mL in the chamber. **P<0.01; ***P<0.005