Abstract
Purpose: :
To study the in vitro toxicity of methylprednisolone on ARPE–19 and R28 cell lines.
Methods: :
ARPE–19 and R28 cells were grown to 100% confluency in serum free DMEM media. Methyl prednisolone acetate suspension (MPA) (Pharmacia & Upjohn Company, Kalamazoo, MI ) was centrifuged to obtain drug (pellet) and supernatant fluid (vehicle).The cells were treated with four different concentrations of drug: 25,50,100 and 500 µg/ml and corresponding four concentrations of vehicle: 18.75, 37.5, 75 and 375 µg/ml. Cell viability was measured at 2, 6 and 24 hours using the trypan blue dye exclusion assay.
Results: :
The mean cell viabilities of ARPE–19 cells after 24 hours exposure to 25,50,100 and 500 µg/ml of pellet were 93.7 ± 1.9% (p>0.05), 84.1±1.2%(p<0.001), 59.4 ±2.6%(p<0.001) and 5.6± 2.0% (p<0.001) respectively, compared to untreated cells that had a viability of 94.7±1.3 % . Cells treated with corresponding concentrations of preservative alone (18.75, 37.5, 75 and 375 µg/ml) had viabilities of 94.2±2.3%, 95.3±2.0%, 94.5±2.1% and 94.6 ±1.6% respectively, which were not significantly different from the viability of untreated ARPE–19 cells. Similarly, the mean cell viabilities of R28 cells after exposure to MPA pellet (25,50,100 and 500 µg/ml) were 90.4± 0.5%(p>0.05),85.7±1.8%(p<0.01), 55.3± 4.2%(p<0.001) and 9.3±1.0% (p<0.001) respectively, compared to untreated R28 cells that had a mean viability of 91.0± 1.0% while the highest corresponding concentration of preservative of 375 µg/ml was not toxic with cell viability of 89.5 ±0.75%.
Conclusions: :
MPA is toxic to ARPE–19 and R28 cells in vitro at the clinical intravitreal dose of 100µg/ml while the preservative is not toxic. This toxicity profile of MPA is similar to that of triamcinolone acetonide in vitro, making it a less valuable alternative for intravitreal injections or implants
Keywords: retinal culture • corticosteroids • injection