Fig. 2

Sigma1R inhibits tachypacing-induced mitochondrial oxidative stress damage in atrial myocytes. HL-1 cells were transfected with Sigma1R overexpressing lentivirus (OE-Sigma1R) or control lentivirus (OE-NC), followed by electrical stimulation for 24 h. (A) Representative transmission electron microscopy images showing mitochondrial morphology in each group (Bar = 500 nm). (B) Quantification of ATP levels across different groups (n = 6). (C) Representative fluorescence microscopy images depicting mitochondrial superoxide production using MitoSOX Red staining (Bar = 100 μm) and quantification of MitoSOX Red fluorescence intensity (n = 3). (D) Representative Mitochondrial membrane potential assessed using fluorescence microscopy (Bar = 100 μm) and quantification of mitochondrial membrane potential across the groups (n = 3). Data are expressed as the mean ± SD. Statistical analysis was performed using one-way ANOVA followed by Tukey’s multiple comparisons test. P^* < 0.05, P^** < 0.01.