Figure 4. SERPINA3K blocks intracellular calcium overload induced by H₂O₂.

(A) Elevated intracellular [Ca²⁺] in cells exposed to H₂O₂. The Müller-derived rMC-1 cells were treated with 400 µM H₂O₂ for various durations as indicated. TBHP (20 µM) was used as control. Intracellular [Ca²⁺] was measured by the fluorescence of the probe Fluo-4/AM (mean±SEM, n = 8). (B–E) The cells were pre-treated with 1 µM SERPINA3K or BSA for 1 h followed by the H₂O₂ exposure. BSA was added to bring the total protein concentration to the same in each well. Representative fluorescence images were captured under a fluorescent microscope from untreated cells (B), cells pre-treated with 1 µM BSA (C) and with 1 µM SERPINA3K (D) followed by a 3-h exposure to H₂O₂. (E) [Ca²⁺] in cells pre-treated with various concentrations of SERPINA3K prior to the exposure to H₂O₂ (mean±SEM, n = 6). (F) The protective effects of 1 µM SERPINA3K and 10 µM BAPTA/AM (a calcium chelator) were quantified using the MTT assay (mean±SEM, n = 3). * P<0.05, ** P<0.01, *** P<0.001, the cells treated by H₂O₂ versus the control cells. # P<0.01, the SERPINA3K or BAPTA-treated cells versus the BSA-treated cells. Scale bar, 100 µm.