Fig. 2

ASIC1a upregulated mitochondrial stress by mediating Ca²⁺ influx. A The effect of ASIC1a on Ca²⁺ in chondrocytes at a pH of 6.0, as detected by calcium imaging. The scale bars are 20 μm. B–D Hsp10, Lonp1, and ClpP mRNA levels in acid-mediated chondrocytes after EGTA pretreatment quantified by real-time q-PCR. E–G HSP10, LONP1, and ClpP expression in acid-mediated chondrocytes after EGTA pretreatment quantified immunofluorescence. The scale bars are 20 μm. H Measurements of ROS released by mitochondria in chondrocytes after pre-treatment with EGTA. I Representative confocal microscopy images of chondrocytes stained with JC-1 after pre-treatment with E2 and EGTA. Red fluorescence indicates normal ΔΨm with JC-1 aggregates in the mitochondria, and green fluorescence reflects the JC-1 monomer, indicative of ΔΨm loss. The scale bars are 20 μm. Data are presented as the mean ± SD of three independent experiments. *P < 0.05, **P < 0.01, ***P < 0.001