Abstract
Abstract: :
Purpose: To study the toxicity of the various components of triamcinolone acetonide on retinal pigment epithelial (ARPE–19) and retinal neurosensory (R28) cells. Methods: Human retinal pigment epithelial cells (ARPE–19, ATCC, Manassas, VA) and rat retinal cells (R28) were grown in tissue culture in Dulbecco's modified Eagle's medium (DMEM, GibgoTM, Calsbad, CA) containing 10% fetal bovine serum. Cells were treated with 50, 100, and 200 µg/mL concentration of triamcinolone acetonide (Kenalog®, Bristol Meyers Squibb, Princeton, NJ) for 2,6, and 24 hours. Samples of the undiluted Kenalog® suspension were centrifuged so that the vehicle (supernatant) and drug pellet could be separately studied for toxicity. Toxicity was measured by the trypan blue dye exclusion (Beckman Coulter Inc., Fullerton, CA) and WST–1 mitochondrial dehydrogenase (Roche Diagnostics, Indianapolis, IN) assays. Results: Vehicle alone did not reduce viability or mitochondrial dehydrogenase activity of ARPE–19 or R28 cells. The mean cell viability of ARPE–19 and R29 cells after exposure to triamcinolone 200 µg/mL for 24 hours were 70.7 ± 10.61% and 75.35 ± 12.42% respectively compared to the untreated ARPE–19 (92.7 ± 6.24 %, p<0.01) and R29 cells (90.63 ± 5.62 %, p<0.001). The mean cell viability of ARPE–19 cells after exposure to triamcinolone pellet (200 µg/mL) was 84.96 ± 0.32 %, 85.2 ± 3.26 %, and 84.73 ± 2.71 % at 2, 6, and 24 hours respectively compared to the untreated ARPE–19 cells (p<0.001). The R28 cells exposed to triamcinolone pellet (200 µg/mL) also had a significant reduction in the mean cell viability at 24 hours (86.42 ± 3.87 %, p<0.001) and 6 hours (89.03 ± 1.01 %, p<0.01). There was a significant reduction in the mitochondrial dehydrogenase activity in the ARPE–19 cells when treated with kenalog or the kenalog pellet at a concentration of 200 µg/mL at all time points (p<0.01). R28 cells did not have any significant reduction in mitochondrial dehydrogenase activity when treated with triamcinolone pellet, but there was a significant reduction when the R28 cells were treated with triamcinolone (200 µg/mL) for 24 hours (p<0.05%). Conclusions: Undiluted triamcinolone and the triamcinolone pellet are toxic to retinal cells in vitro at doses lower than normally used in clinical practice. The vehicle appears to be non–toxic to the cells. The exact mechanism of the toxicity needs to be further evaluated.
Keywords: retina • drug toxicity/drug effects • retina: neurochemistry