A Contraction Assay System Using Established Human Bronchial Smooth Muscle Cells

<i>Background:</i> To further understand the mechanisms of airway obstruction in asthma, it is crucial to investigate contractile responses of human airway smooth muscle. An in vitro assay system employing collagen gels embedded with well-established bronchial smooth muscle cells of human origin was explored in the present study. <i>Methods:</i> Commercially available cultured human bronchial smooth muscle cells were embedded into a collagen gel. Well-known constrictors, histamine and methacholine, were added to the gel. The gel images were captured by an image analyzer, and contractile responses were evaluated. <i>Results:</i> Histamine and methacholine induced contraction of the gels in a dose-dependent manner. Pyrilamine, an H₁ receptor antagonist, inhibited gel contraction in an agonist-specific manner. <i>Conclusion:</i> Our contraction assay system, employing widely distributed cultured cells, was highly reproducible and precise. It may go a long way toward understanding mechanisms of asthmatic responses and evaluation of antiasthma drugs.