Abstract
Purpose: :
To evaluate the in vitro effect of combined dexamethasone and bevacizumab treatment with photodynamic therapy (PDT) using verteporfin on the cell viability of the retinal pigment epithelial (RPE) cells.
Methods: :
Human retinal pigment epithelial cells (ARPE-19) were treated with two different concentrations of dexamethasone (0.1 and 0.2 mg/ml) and bevacizumab (0.125 and 0.25 mg/ml) in conjunction with or without verteporfin PDT. Cell viability was measured using cell count (%) and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) assay at 2 hours, 24 hours, and 48 hours after combined therapy.
Results: :
The cell viabilities of ARPE-19 cells, treated with dexamethasone or bevacizumab only, were not significantly different (P > 0.05) from those of untreated controls at all time points and concentrations irrespective of PDT. The lack of cytotoxic effect of combined 0.1 mg/ml dexamethasone and 0.125mg/ml bevacizumab treatment with or without PDT on ARPE-19 cells could be observed at all periods. The MTT assay decreased to 91.3 ± 6.0% (p=0.009), 94.7 ± 4.7% (p=0.045), and 92.9 ± 6.2% (p=0.034) respectively, after 2 hours, 24 hours, and 48 hours of direct exposure to both 0.2mg/ml dexamethasone and 0.25 mg/ml bevacizumab with PDT. The number of viable cells also decreased by 93.4 ± 3.0% (p=0.032), 90.7 ± 6.0% (p=0.001), and 93.5 ± 3.9% (p=0.034) respectively, after 2 hours, 24 hours, and 48 hours of direct exposure to both dexamethasone 0.2 mg/ml and 0.25mg/ml bevacizumab with PDT.
Conclusions: :
In vitro, 0.2 mg/ml dexamethasone and 0.25mg/ml bevacizumab combination therapy, usually used for treatment of choroidal neovascularization, is toxic to ARPE-19 cells irrespective of PDT.
Keywords: retinal pigment epithelium • cell survival • drug toxicity/drug effects