Sulfur mustard (SM) is a cytotoxic, vesicating, chemical warfare agent, first used in 1917; corneas are particularly vulnerable to SM exposure. They may develop inflammation, ulceration, neovascularization (NV), impaired vision, and partial/complete blindness depending upon the concentration of SM, exposure duration, and bio-physiological conditions of the eyes. Comprehensive in vivo studies have established ocular structural alterations, opacity, NV, and inflammation upon short durations (<4 min) of SM exposure. In this study, detailed analyses of histopathological alterations in corneal structure, keratocytes, inflammatory cells, blood vessels, and expressions of cyclooxygenase (COX)-2, matrix metalloproteinase (MMP)-9, vascular endothelial growth factor (VEGF), and cytokines were performed in New Zealand white rabbits, in a time-dependent manner till 28 days, post longer durations (5 and 7 min) of ocular SM exposure to establish quantifiable endpoints of injury and healing. Results indicated that SM exposure led to duration-dependent increases in corneal thickness, opacity, ulceration, epithelial-stromal separation, and epithelial degradation. Significant increases in NV, keratocyte death, blood vessels, and inflammatory markers (COX-2, MMP-9, VEGF, and interleukin-8) were also observed for both exposure durations compared to the controls. Collectively, these findings would benefit in temporal delineation of mechanisms underlying SM-induced corneal toxicity and provide models for testing therapeutic interventions.
Predicting the hydrolytic breakdown rates of organophosphorus chemical warfare agent simulants using association constants derived from hydrogen bonded complex formation events
