Nerve growth factor induces airway hyperresponsiveness in mice

Background: Previous studies indicated an upregulation of nerve growth factor (NGF) production during allergic inflammation. However, the function of NGF in the lungs is currently poorly understood. It was suggested that NGF could play an important role in the pathophysiology of airway hyperresponsiveness. The regulatory network between immunological events and altered neuronal control of airway smooth muscle contractility remains to be defined.

Methods: NGF was delivered into the airways of mice either by nasal instillation or by genetic engineering. Airway reactivity was then measured by electrical field stimulation.

Results: Treatment of mice with NGF induced airway hyperresponsiveness to a similar extent as demonstrated in allergen-sensitized mice. NGF-transgenic mice, overexpressing NGF in Clara cells, were hyperreactive in comparison to wild-type mice.

Conclusion: These data suggest that NGF by itself determines the induction of airway hyperresponsiveness in the absence of airway inflammation in mice.