Acute urticaria[corrected]-like lesions in allergen-unexposed cutaneous tissues in a mouse model of late allergic rhinitis

Circadian Pharmacological Effects of Paeoniflorin on Mice With Urticaria-like Lesions

Paeoniflorin (PF) is a monoterpene glucoside with various biological properties, and it suppresses allergic and inflammatory responses in a rat model of urticaria-like lesions (UL). In the present study, we treated OVA-induced mice presenting UL with PF at four circadian time points (ZT22, ZT04, ZT10, and ZT16) to determine the optimal administration time of PF. The pharmacological effects of PF were assessed by analyzing the scratching behavior; histopathological features; allergic responses such as immunoglobulin E (IgE), leukotriene B4 (LTB4), and histamine (HIS) release; inflammatory cell infiltration [mast cell tryptase (MCT) and eosinophil protein X (EPX)]; and mRNA levels of inflammatory cytokines such as interleukin (IL)-12, IL-6, interferon-γ (IFN-γ), and IL-4. It was demonstrated that PF significantly alleviated scratching behavior and histopathological features, and ZT10 dosing was the most effective time point in remission of the condition among the four circadian time points. Moreover, PF decreased the serum levels of IgE, LTB4, and HIS, and PF administration at ZT10 produced relatively superior effectiveness. PF treatment, especially dosing at ZT10, significantly reduced the number of mast cells and granules and diminished the infiltration of MCT and EPX in the skin tissues of mice with UL. Furthermore, the oral administration of PF effectively decreased the inflammatory cytokine levels of IL-12 mRNA. In conclusion, different administration times of PF affected its efficacy in mice with UL. ZT10 administration demonstrated relatively superior effectiveness, and it might be the optimal administration time for the treatment of urticaria.

Regulation of the development of asthmatic inflammation by in situ CD4(+)Foxp3 (+) T cells in a mouse model of late allergic asthma

CD4(+)Foxp3(+)T cells (Tregs) mediate homeostatic peripheral tolerance by suppressing helper T2 cells in allergy. However, the regulation of asthmatic inflammation by local (in situ) Tregs in asthma remains unclear. BALB/c mice sensitized and challenged with ovalbumin (OVA) (asthma group) developed asthmatic inflammation with eosinophils and lymphocytes, but not mast cells. The number of Tregs in the circulation, pulmonary lymph nodes (pLNs), and thymi significantly decreased in the asthma group compared to the control group without OVA sensitization and challenge in the effector phase. The development of asthmatic inflammation is inversely related to decreased Tregs with reduced mRNA expression such as interleukin (IL)-4, transforming growth factor-β1, and IL-10, but not interferon-γ, in pLNs. Moreover, M2 macrophages increased in the local site. The present study suggests that Tregs, at least in part, may regulate the development of asthmatic inflammation by cell-cell contact and regional cytokine productions.

Reovirus type-2 infection in newborn DBA/1J mice reduces the development of late allergic asthma

The aim of the present study was to determine whether or not the development of a helper T (Th) 1 response induced by Reovirus type-2 (Reo-2) infection would protect against the development of Th2-mediated late allergic asthma. This hypothesis was examined by infecting one day old neonatal DB A/1J mice with Reo-2 in an ovalbumin (OVA)-induced late asthma model. Compared with the controls (either infected or uninfected mice with or without OVA sensitization and/or OVA challenge), Reo-2 infection lessened the magnitude of the subsequent allergic Th2-mediated late asthma. In infected mice with allergic late asthma, there was decreased infiltration of interleukin (IL)-4(+), IL-5(+), IL-13(+) and very late antigen (VLA)-4(+) lymphocytes, and eotaxin-2(+) and VLA-4(+) eosinophils, in both bronchial and bronchiolar lesions. Also the expression of vascular cell adhesion molecule (VCAM)-1 and eotaxin-2 on vascular endothelial cells was reduced. Moreover, the systemic production of IL-4, IL-5, tumour necrosis factor-α and OVA-specific IgE was reduced, whereas systemic IFN-γ production was increased. In addition, there was no increase in IFN-α production. Thus the present study suggests that systemic Reo-2 infection at birth may reduce the development of subsequent late allergic asthma by the induction of a Th1 response. Therefore the potential suppressive mechanism(s) that might be induced by Reo-2 infection in newborn mice and their effects on the development of late allergic asthma are discussed.

Eosinophilic venulitis in the small intestines in a mouse model of late asthma

The allergen-unchallenged enteric lesions in late allergic asthma are largely unknown. To clarify this point, BALB/c mice were sensitized by ovalbumin (OVA)/aluminum adjuvant intraperitoneally two times (on days 0 and 10) and then challenged with OVA intranasally on day 14 (asthma group). Four days after the challenge, small intestinal lesions were examined. By this treatment, diarrhea was not observed in the asthma group. Compared to the controls with or without OVA sensitization and/or OVA challenge, the asthma group developed eosinophilic venulitis without an increase in mucosal mast cells in small intestines, whereas intestinal epithelial cells were relatively intact. A few numbers of interleukin (IL)-4(+) and IL-5(+) lymphoid cells were recognized in intestines in the asthma group, but not in the controls. Expression of vascular cell adhesion molecule-1 on venular endothelium and eotaxin-2(+) eosinophils, but not epithelial cells, in intestines were detected in the asthma group, but not in the controls. Total IgE, OVA-specific IgE and eotaxin, and IL-5, but not interferon-γ, were produced systemically in the asthma group compared to the controls. The present study suggests that eosinophilic venulitis without mast cells in the intestine may be induced by the systemic, but not by local, helper T 2-type responses. In addition, eosinophilic venulitis in small intestines may be subclinical enteric lesions.