Repeated exposures to the environmental allergen methylisothiazolinone reduce viability of fibroblasts derived from allergic sites in response to allergen challenge in vitro

Abstract

Chronic, unexplained vulvar pain or vulvodynia affects 8% of women of reproductive age, and is more common with histories of yeast infections and allergies. We have established mouse models of localized, provoked genital pain driven by repeated labiar and vaginal exposures to allergens such as oxazolone, dinitrofluorobenzene and the common chemical preservative methylisothiazolinone (MI). Pain sensitivity is concomitant with tissue mast cell increases and reduced when mast cells are reduced by chemical degranulation or topical phytocannabinoid treatment. Vulvar fibroblasts from patients show altered inflammatory responses in vitro.to repeated topical application of the allergenic cosmetic preservative methylisothiazolinone (MI) to the murine vaginal canal produces long-lasting contact hypersensitivity. Here, we have optimized methods to grow skin and vaginal canal fibroblasts from outbred Swiss mice that are responsive to lipopolysaccharide and zymosan treatment in vitro. We also show that in vitro MI treatment reduces the viability of derived fibroblasts in a dose-dependent manner, with a more robust effect on cell lines derived from MI-treated skin, indicating that previous exposure to MI in the skin primes fibroblasts to undergo cell death upon future exposures. Our data suggest that fibroblasts may become more sensitive to allergens as a result of previous exposures, which could contribute to the development of chronic allergic and pain sensitivity after repeated low dose chemical exposures.