Fig. 2. Effect of Ang II on apoptosis with CaMKII oxidation. Cells were isolated from right atria and incubated with FBS for 1 day or 3 days. (A) Following the indicated days, protein was extracted to determine TBX3 (sinus node marker) and MLCA2 (cardiomyocyte marker) using Western blotting. Cells with dominant TBX3 expression were isolated and maintained using 20% FBS-DMEM. Subsequently, Ang II (20 µM) was added to the culture medium for 5 days. (B) Apoptotic cells were counted using TUNEL assay. Protein was extracted to measure caspase-3 activity (C) and determined ox-CaMKII and T-CaMKII using Western blotting (D). Ang II, angiotensin II; CaMKII, calmodulin kinase II; DMEM, Dulbecco's modified Eagle's medium; FBS, fetal bovine serum; ox-CaMKII, oxidized-CaMKII; PBS, phosphate buffered saline; T-CaMKII, total CaMKII; TUNEL, terminal deoxynucleotidyl transferase dUTP nick end labeling. Data are shown as the means±SEM of 3-6 mice per group. ^a)Significantly different (P<0.05) from PBS treated control. ^b)Significantly different (P<0.05) from right atrial cells at 1st day. Scale bar=50 µm.