Abstract
Purpose: :
Our recent studies suggest that short chain aliphatic β-nitro alcohols can cross-link corneal tissue under physiologic temperature and pH. The present study was conducted in order to determine the cytotoxic threshold for these agents in vitro and to draw comparisons to commonly used topical ophthalmic agents.
Methods: :
Primary cultures of bovine corneal endothelial cells were grown to confluence in 24-well plates using standard protocol. The cells were then exposed to three β-nitro alcohols, 2-nitroethanol, 2-nitro-1-propanol, and 3-nitro-2-pentanol in a range of concentrations from 0.1mM to 10mM. Following a 48 hr exposure, the cells were evaluated for cytotoxic effects using Trypan blue staining. The cytotoxic levels were then compared to reported values of other topical ophthalmic agents based on a review of the literature.
Results: :
An all-or-none response was observed for each compound. 2-nitro-1-propanol was most toxic. The cytotoxic level for 2-nitroethanol, 2-nitro-1-propanol, and 3-nitro-2-pentanol was 0.0273% (3 millimolar), 0.0105% (1 millimolar), and 0.0399% (3 millimolar), respectively. By comparison, the toxicity level reported is ~0.0001% (~3 micromolar) for fluoroquinolone antibiotics (i.e. ciprofloxacin, gatifloxacin, and moxifloxacin), 0.001% for benzalkonium chloride, 0.005% (220 micromolar) for azathioprine, and 0.1% for providone iodine.
Conclusions: :
Short chain aliphatic β-nitro alcohols are less toxic in vitro than many of the compounds currently in use in ophthalmic practice, suggesting a favorable safety profile. Future studies using living eyes will be necessary in order to determine their pharmacologic utility.
Keywords: cornea: endothelium • apoptosis/cell death • sclera