Abstract
Purpose: :
To evaluate the effects of commercially available preservative free triamcinolone acetonide (Triesence®) on retinal cells in culture.
Methods: :
Human RPE (ARPE-19) and rat retinal neurosensory (R28) cell cultures were treated with 100, 200, 500 or 1000 µg/ml of crystalline (c) or solubilized (s) TRI for 24 hours. Triesence was solubilized by first centrifuging the drug and then discarding the supernatant containing the vehicle and preservative. The drug pellet was resuspended in an equivalent amount of Dimethyl sulfoxide (DMSO) to achieve the same concentration as the commercial preparation. Cell Toxicity was evaluated by trypan blue dye-exclusion assay (cTRI and sTRI), JC1 assay to measure mitochondrial damage (sTRI only), and caspase-3/7 activity to measure apoptosis (sTRI).
Results: :
Compared to untreated controls, cTRI caused a decrease in cell viability in all concentrations and cell lines tested (13.03±6.51, 28.87±9.3, 54.93±5.61 and 82.53±0.65 for ARPE 1000, 500, 200 and 100 µg/ml vs. 96.98±0.16 for untreated controls, p<0.001, except for 100 µg/ml vs. untreated, p<0.05; 22.73±2.44, 34.63±1.91, 58.70±1.39 and 75.33±2.47 for R28 1000, 500, 200 and 100 vs. 86.08±3.54 for untreated controls, p<0.001). sTRI did not reduce viability or JC1 mitochondrial membrane potential of either cell line at any concentration tested. However, caspase 3/7 upregulation was detected in both cell lines. For the ARPE-19 it was observed when sTRI 200, 500 and1000 µg/ml was compared to untreated cells or DMSO controls (p<0.01). For R28 cells, caspase 3/7 upregulation was observed when compared sTRi 200, 500 and 1000 µg/ml to DMSO controls (P<0.05 for 200 µg/ml, p<0.01 for 500 and 1000 µg/ml) but only 1000 µg/ml was statistically significant when compared to untreated cells (P<0.01).
Conclusions: :
Crystalline Triesence® causes significant decrease in cell viability in retinal cells in culture. Cell death was not observed after the drug was solubilized, though caspase 3/7 upregulation was noted. This suggests that Triesence® can damage retinal cells in vitro via caspase-dependent apoptosis, similar to Kenalog® and compounding pharmacy produced preservative-free triamcinolone.
Keywords: retinal culture • retinal pigment epithelium • ocular irritancy/toxicity testing