Figure 1.

MitoTEMPO suppressed IR-induced increases in ROS_mt, [Ca²⁺]_mt, and [Ca²⁺]_i in submandibular acinar cells. (a) ROS_mt was measured by monitoring the fluorescence of ROS_mt indicator dye MitoSOX. Cells were first maintained in Ca²⁺-free medium to measure basal levels of ROS_mt (basal fluorescence). Ca²⁺ was then added to the external medium and Ca²⁺-dependent increase in fluorescence was measured. Traces in the left panel shows representative MitoSOX fluorescence changes in the three groups of cells, middle panel shows quantitation of data for basal ROS_mt and right panel shows Ca²⁺-dependent increase in ROS_mt. Data were obtained from 132 to 152 cells from at least 3 different experiments. Values marked as *p < 0.05 and **p < 0.01 indicate significant difference as compared with CTL and IR + MitoTEMPO values (using unpaired t test). Unmarked values are not different from each other. (b) [Ca²⁺]_mt was monitored by measuring the Rhod-2 fluorescence in cells under Ca²⁺-free conditions and after Ca²⁺ was added to the external medium. Similar sets of cells were used as in (a). Traces are shown in left panel, and quantitation of the data are shown in the middle and right panels; basal [Ca²⁺]_mt and Ca²⁺-dependent increase in [Ca²⁺]_mt, respectively. Data were obtained from 124–144 cells from at least 3 different experiments. Values marked as **p < 0.01 and *p < 0.05 indicate significant difference as compared to the CTL and IR + MitoTEMPO values. Unmarked values are not different from each other. Statistical comparisons were done using unpaired t test. (c) [Ca²⁺]_i was monitored by measuring the fura-2 fluorescence in cells maintained in Ca²⁺-free conditions and after Ca²⁺ was added to the external medium. Traces are shown in the in left panel, quantitation of data in middle and right panels are shown as basal changes of [Ca²⁺]_i and Ca²⁺-dependent increase in [Ca²⁺]_i after re-addition of external Ca²⁺. Data were obtained from 120–128 cells from at least 3 different experiments. Values marked as **p < 0.01 and *p < 0.05 are significantly different as compared with CTL and IR + MitoTEMPO. Unmarked values are not different from each other. Unpaired t test was used to determine statistical significance of data. Values shown are mean ± SEM in each case.