Protector mechanisms of the association between gastroesophageal reflux disease and asthma: experimental study in rats.
BACKGROUND
It is well known the association between gastroesophageal reflux disease and asthma. The hyperreactivity of the airways is a characteristic of an asthmatic. Many studies associate the increase of the airways reactivity with gastroesophageal reflux disease.


OBJECTIVE
In this study we have evaluated the effect of the intraluminal exposition to gastric juice of trachea on the reactivity to methacholine from rats submitted to a pulmonary allergic inflammation.


METHODS
Group of rats were sensitized and challenged with ovalbumin. After 24 hours the animals were sacrificed, and their tracheae were removed to be cultured with gastric juice. The gastric juice was obtained from a donor rat. Subsequently the segments were placed into plastic plates with RPMI-1640 for incubation, under suitable atmosphere and time. After the period of incubation the segments were put into chambers for the analysis of the contractile response to methacholine.


RESULTS
We observed reduction in the contractile response of trachea cultured with gastric juice from allergic rats. This result was confirmed by the pharmacological treatments with compound 48/80 and dissodium cromoglicate (mast cells blockade), L-NAME (nitric oxide inhibitor, NO), capsaicin (neuropeptides depletion) and indomethacin (ciclooxigenase inhibitor).


CONCLUSIONS
Our results highlight to the existence of a complex interaction between pulmonary allergy and gastric juice in the airways. The involvement of the non-adrenergic non-cholinergic system, NO, prostanoids and mast cells are directly related to this interaction. We suggest that the reduced contractile response observed in vitro may represent a protector mechanism of the airways. Despite its presence in the human body it can not be observed due to the predominant effects of excitatory the non-adrenergic non-cholinergic system.
Department of Public Health Practice, Faculty of Public Health, University of São Paulo, São Paulo, SP, Brazil.
Paula Yuri Sugishita
PY
Kanikadan
Jayme Antonio Aboin
JA
Sertié
Ricardo Martins
RM
Oliveira-Filho
Wothan Tavares de
WT
Lima
D000818:Animals; D001249:Asthma / Q000139:chemically induced / Q000150:complications* / Q000503:physiopathology; D016535:Bronchial Hyperreactivity / Q000139:chemically induced / Q000503:physiopathology*; D016085:Bronchoconstrictor Agents / Q000494:pharmacology; D005764:Gastroesophageal Reflux / Q000150:complications* / Q000503:physiopathology; D008297:Male; D016210:Methacholine Chloride / Q000494:pharmacology; D010047:Ovalbumin / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar
D016085:Bronchoconstrictor Agents; D016210:Methacholine Chloride; D010047:Ovalbumin