Murine allergic conjunctivitis
Allergic conjunctivitis is one of the most common ocular complaints in humans. Topical instillation of compound 48/80 triggers mast cell degranulation in the conjunctiva of the mouse. This is a reliable and simple model. The conjunctivitis is characterized clinically by irritation, discharge, erythema, and chemosis and histopathologically by infiltrations of neutrophils, macrophages, some T cells and a few eosinophils. Late phase inflammatory reaction peaks 6 to 24 hours after compound 48/80 administration and resolves by 48 to 72 hours. Recently, a second model of murine allergic conjunctivitis is also developed (Magone et al. Clin Immunol Immunopathol 1998;87:75-84). Mice are immunized with short ragweed pollen in aluminum hydroxide. Allergic conjunctivitis is induced by one topical application of ragweed pollen onto the eye. Immediate response includes conjuctival chemosis and redness, lid edema and discharge. Conjuctivum is infiltrated with neutrophils, macrophages, and lymphocytes. Th2-type cytokines and ragweed-specific IgG1 and IgE are detected.
Both models allow us to study the genetic factors for allergy, the mechanism of allergic conjunctivitis, and to evaluate the effects of various topical anti-inflammatory or anti-allergic medications (e.g., corticosteroids, cyclosporine, nedocromil, immunostimulatory DNA sequence oligonucleotide) on allergic conjunctivitis. The second model is especially valuable for understanding the pathophysiology of ocular allergy and assessing the efficacy of the drugs on inhibiting leukocyte and monocyte infiltration associated with an IgE reaction.
|Left: normal conjunctiva externally (top) and microscopically (bottom)
Right: allergic conjunctivitis with swelling watery closed eyelids (top) and allergic conjunctivitis with subacute inflammation and edema (bottom).