1. Time course changes of scratching counts, dermatitis symptoms, and levels of cutaneous prostaglandins in NC/Nga mice.
- Author
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Sugimoto, Masanori, Arai, Iwao, Futaki, Nobuko, Hashimoto, Yuki, Sakurai, Takanobu, Honma, Yusuke, and Nakaike, Shiro
- Subjects
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SKIN inflammation , *PROSTAGLANDINS , *MICE , *PATHOGENIC microorganisms , *HEMATOPOIESIS , *ARACHIDONIC acid - Abstract
NC/Nga (NC) mice are known to develop dermatitis resembling atopic dermatitis (AD) in conventional (Conv) conditions, but not in specific pathogen-free (SPF) conditions. We reported that the ability of skin prostaglandin D2 (PGD2) production, which might be the endogenous inhibitor of itching, was attenuated in skin-lesioned Conv-NC mice. We examined the age-related change in scratching, dermatitis symptoms, and skin PGs of SPF- and Conv-NC mice. In Conv-NC, PGD2 increased at 7 weeks, at which scratching counts increased, but dermatitis did not develop. PGE2, PGI2 and PGF2 α increased at 10 and 13 weeks, at which dermatitis developed. The ability to produce skin PGs was examined by measuring PGs after application of arachidonic acid or after mechanical scratching using a wire brush. In Conv-NC, PGD2 production at 13 weeks was lower than at 7 weeks. In Conv-NC, hematopoietic PGD synthase (hPGDS) expression in the skin at 13 weeks was lower than at 7 weeks by Western blotting and immunohistochemical analysis. The increase of skin PGD2 level in the early phase of the development of dermatitis is due to the stress of extensive scratching, but did not increase in spite of the stress of extensive scratching in the late phase, due to decreasing capacity of PGD2 production attributable to decreasing hPGDS expression in Conv-NC mice. These results suggest that a decreased ability to produce skin PGD2 production could enhance scratching and aggravate dermatitis in Conv-NC mice. [ABSTRACT FROM AUTHOR]
- Published
- 2006
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