To assist in confirming that mitochondria were a major site of ROS production in hyperthermia-treated platelets, we used MitoSOXTM Red fluorescence, which detects superoxide synthesis, to quantify mitochondrial ROS (Figure 2A and 2B). We found that mitochondrial superoxide production was increased with increasing temperature and in a time-dependent manner. In addition, Mito-TEMPO significantly inhibited hyperthermia-induced mitochondrial ROS generation as compared with the solvent control (Figure 2C). By contrast, inhibitors of NADPH oxidase, NOS, COX and LOX did not (Figure 2C). Together, these observations further confirm that hyperthermia might increase mitochondrial ROS production in platelets. As a positive control, washed platelets were incubated with antimycin A, which is known to increase mitochondrial ROS production [35]. We found that antimycin A markedly induced mitochondrial ROS production in platelets (Figure 2B).