Abstract
Purpose: :
Cataracts are considered the leading cause of blindness worldwide accounting for approximately 48% of all reported cases. While advances in surgical techniques, intraocular lens (IOL) materials and IOL designs have been made, there is still a significant risk of posterior capsule opacification (PCO) following cataract surgery. Inhibition of matrix metalloproteinases (MMPs) by the antibiotic sulfadiazine has been shown to potentially decrease the incidence of PCO. However, it is desirable to determine the optimal therapeutic concentration of sulfadiazine necessary to minimize the likelihood of PCO.
Methods: :
The in vitro production of epithelial-to-mesenchymal transition (EMT) markers was measured. On Day 1, an infant derived human lens epithelial cell line, HLE-B3, was seeded at a density of 2 000 cells per surface and incubated at 5% CO2 and 37°C in MEM-F15 media. On Day 3, cells were exposed to 10 ng/mL of transforming growth factor beta (TGF-β). On Day 4, varying concentrations (0.0 mM, 0.025 mM, 0.075 mM, 0.125 mM, 0.175 mM and 0.225 mM) of sulfadiazine were added to the cultures. On Day 6, cultures were assayed for the production of fibronectin and laminin using rabbit anti-fibronectin primary antibody (1:300) and rabbit anti-laminin primary antibody (1:300), respectively. Production of the migration marker Rho was also assayed using a rabbit anti-Rho primary antibody (1:300). An anti-rabbit Rhodamine Red-X secondary antibody (1:100) was used following primary antibody incubation in each assay. Alpha smooth muscle actin (α-SMA) production was measured using FITC-labeled anti-α-SMA antibody (1:900). All fluorescence measurements were conducted using a PerkinElmer 1420 multilabel fluorometer. Lastly, collagen production was measured following incubation with a 0.02% Sirius red (Red 80) solution using a Bio-Rad 550 microplate reader. Determination of MMP inhibition is ongoing.
Results: :
Varying the sulfadiazine concentration had a significant effect on the production of EMT markers. In the case of each EMT marker, a decrease in marker production was shown with increasing sulfadiazine concentrations up to 0.125 mM. Increasing the sulfadiazine concentration in the media beyond this value resulted in a negative response and increased marker production in all cases. With a sulfadiazine concentration of 0.125 mM, marker production decrease ranged from 4% for collagen up to 25% for α-SMA.
Conclusions: :
These results show that sulfadiazine may have MMPI activity, therein providing a viable option for the mitigation of PCO following cataract surgery. Moreover, determination of the most effective therapeutic dose is crucial when considering further tests involving in vivo studies and drug delivery devices such as IOLs.
Keywords: posterior capsular opacification (PCO) • cataract • drug toxicity/drug effects