Age-related difference in the persistency of allergic airway inflammation and bronchial hyperresponsiveness in a murine model of asthma.
OBJECTIVE
Asthmatic children are more likely to outgrow their symptoms than adult patients. Thus, we wanted to know whether there were any age-related differences in the time course of the allergic airway inflammation.


METHODS
BALB/C mice at different ages (young: 3 days after birth, and mature: 8 weeks of age) were sensitized with ovalbumin (OVA). Subsequently, animals were challenged with aerosolized OVA during 1, 2, 4 or 8 consecutive weeks. Bronchial hyperresponsiveness (BHR), serum IgE levels, the degrees of inflammatory cell infiltration (ICI) and goblet cell metaplasia (GCM) in the airways, and the number of eosinophils and cytokine levels in bronchoalveolar lavage fluid (BALF) were examined.


RESULTS
At 1 week, airway inflammation and BHR occurred similarly between young and mature mice. However, BHR disappeared at 4 weeks in young, whereas it persisted even at 8 weeks in mature mice. GCM, ICI and eosinophilia in BALF attenuated with time, with more remarkable reduction in young mice. The BALF IL-4 level was high during the first 2 weeks in both groups, while the IL-2 level was significantly increased at 2 weeks solely in young mice.


CONCLUSIONS
Different time courses in airway inflammation and in BHR may relate to the different prognoses between childhood and adult asthma. The understanding of the mechanisms underlying this age-related differences may be helpful to induce remission in asthmatic patients.
Mayuzumi
Hiroo
H
Department of Pediatrics and Developmental Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan.
Ohki
Yasushi
Y
Tokuyama
Kenichi
K
Sato
Akira
A
Mizuno
Takahisa
T
Arakawa
Hirokazu
H
Mochizuki
Hiroyuki
H
Morikawa
Akihiro
A
D000367:Age Factors; D000375:Aging / Q000276:immunology*; D000818:Animals; D000831:Animals, Newborn; D001249:Asthma / Q000276:immunology / Q000473:pathology; D016535:Bronchial Hyperreactivity / Q000276:immunology* / Q000473:pathology*; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry / Q000276:immunology; D016207:Cytokines / Q000096:biosynthesis; D004195:Disease Models, Animal; D051379:Mice; D008807:Mice, Inbred BALB C; D012130:Respiratory Hypersensitivity / Q000276:immunology* / Q000473:pathology*
D016207:Cytokines