Involvement of IL-31 on scratching behavior in NC/Nga mice with atopic-like dermatitis.
Pruritus is an important symptom in atopic dermatitis (AD), but the major pruritogen has not been identified. NC/Nga mice, spontaneously develop an eczematous AD-like skin lesion when kept under conventional conditions, but not under specific pathogen-free (SPF) conditions, have been thought to be an animal model for AD. In this study, to determine whether newly identified cytokine, IL-31, may be involved in pruritus of AD, we examined the IL-31 expression in spontaneous dermatitis model which showed itch-associated long-lasting (over 1.5 s duration) scratching behavior and compared with that of hapten-induced contact dermatitis model without itch-associated long-lasting scratching behavior, using NC/Nga mice. In NC/Nga mice cohabited with NC/Nga mice which developed severe dermatitis for 2 weeks (conventional NC/Nga mice), the numbers of long-lasting scratching counts were significantly increased. Yet in 2,4,6-trinitrochlorobenzene (TNCB)-sensitized and challenged mice (TNCB-applied NC/Nga mice), no significant increase in long-lasting scratching counts was observed. In conventional NC/Nga mice with long-lasting scratching behavior, expression of IL-31 mRNA was increased, while in TNCB-applied NC/Nga mice without long-lasting scratching behavior, the expression of IL-31 mRNA were unchanged. There was a good correlation between the scratching counts and expression of IL-31 mRNA in conventional NC/Nga mice, but not so in TNCB-applied NC/Nga mice. These results suggest that IL-31 causes the itch-associated scratching behavior in conventional NC/Nga mice, an experimental animal model for AD.
Takaoka
A
A
Medicinal Pharmacology Laboratory, Taisho Pharmaceutical Co. Ltd, 1-403 Yoshino-cho, Kita-ku, Saitama 331-9530, Japan. a.takaoka@po.rd.taisho.co.jp
Arai
I
I
Sugimoto
M
M
Honma
Y
Y
Futaki
N
N
Nakamura
A
A
Nakaike
S
S
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D016207:Cytokines / Q000378:metabolism; D003876:Dermatitis, Atopic / Q000503:physiopathology*; D004817:Epidermis / Q000503:physiopathology; D015870:Gene Expression; D007249:Inflammation / Q000503:physiopathology; D007378:Interleukins / Q000502:physiology*; D008297:Male; D051379:Mice; D011537:Pruritus / Q000503:physiopathology*; D012333:RNA, Messenger / Q000378:metabolism; D014870:Water Loss, Insensible / Q000502:physiology
D016207:Cytokines; D007378:Interleukins; D012333:RNA, Messenger