Lowering Intracellular Calcium Concentration May Reduce the Cytotoxicity of Triamcinolone on Human Retinal Pigment Epithelial (ARPE19) Cells

Abstract

1. The present study investigated the use of drugs that affect calcium (Ca^{2 +}) levels and thus reduction of triamcinolone (TA)‐induced cytotoxicity on human retinal epithelial (ARPE19) cells. 2. Four groups were compared: ARPE19 cells alone, cells exposed to TA (0.1 mg/mL), cells that have been pretreated with one of the testing agents for 30 min before the addition of TA, and cells that have only been treated with one of the testing agents. Pinacidil (PIN) and its analogue, P1060, were used to test the effect of potassium (K⁺) channel opening on TA‐induced toxicity. Verapamil (VP) and diltiazem (DZ) were used to test their Ca^{2 +} channel blocking effect. The cell viability under different settings was assessed using 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay. Ca^{2 +}‐imaging was used to determine the changes in intracellular Ca^{2 +} levels [(Ca^{2 +})_i] upon different treatments. 3. Both PIN and P1060 reduced TA‐induced toxicity. Verapamil and DZ increased the viability of cells treated with TA significantly, suggesting that the excessive influx of Ca^{2 +} was one of the main contributory factors to the TA‐induced toxicity. 4. The results suggest that the prevention of Ca^{2 +} entry may be effective in the reduction of cell necrosis in the presence of TA.

Keywords :

• Triamcinolone
• Cytotoxicity
• Ion channel modulators
• Calcium