Abstract
Abstract: :
Purpose:Mouse mast cell proteases (mMCPs), mMCP–1, 2, 4, 5, 6, 7, and carboxypeptidase A (CPA), are most abundantly stored mediators in mast cells and have been implicated as indispensable players to affect late phase reaction and chronic inflammation. Depending on the site harboring mast cells, expression profile of the mMCPs differs. It is also known that mast cell reactivity is tissue dependent. Thus, mMCPs expression profile may also be related with reactivity. In allergic conjunctivitis, repeated exposure to allergen aggravates or induces clinical symptoms as well as tissue remodeling. In this study, we sought to evaluate whether repeated allergen exposure relates with changes in mast cell lineage as well as clinical signs of immediate hyperreactivity. Methods:Twenty eight days after sensitization by short ragweed pollen (day –28), SWR/J mice were induced immediate hypersensitivity by topical short ragweed instillation for 7 consecutive days (day 0–day 6). Early phase clinical symptoms (sum of chemosis/lid edema/conjunctival redness/discharge score 0–16) were evaluated 20 min after every allergen exposure by slit lamp. To examine reactivity of mast cells, the mice ware sacrificed on days 0, 1, 3 and 7, and the expression of mMCPs were analyzed by RT–PCR. The expression of FcεRIß, which is limited to mast cells, was examined to verify the activation of mast cells on IgE. Results:Repeated allergen exposure aggravated clinical score (control–PBS 4.2+/–0.6; 8.9+/–0.2 at day 0, 10.4+/–0.5 at day 2, 11.1+/–0.3 at day 4, P<0.05 ANOVA). Beginning of day 3, mMCP–4, 5, 6, 7 and CPA were enhanced during the course of exposure. Interestingly, mMCP–1 and 2, which are not normally expressed in the ocular surface, was induced on days 3 and 7. FcεRIß was also strongly enhanced on days 3 and 7 and activation status of mast cells was confirmed. Conclusions:These results implicate mast cell profiling dynamically changes in the course of allergic conjunctivitis, and it is related with clinical signs of immediate hyperreactivity.
Keywords: conjunctiva • conjunctivitis