Assays for in vitro monitoring of proliferation of human airway smooth muscle (ASM) and human pulmonary arterial vascular smooth muscle (VSM) cells

Vascular and airway remodeling, which are characterized by airway smooth muscle (ASM) and pulmonary arterial vascular smooth muscle (VSM) proliferation, contribute to the pathology of asthma, pulmonary hypertension, restenosis and atherosclerosis. To evaluate the proliferation of VSM and ASM cells in response to mitogens, we perform a [³H]thymidine incorporation assay. The proliferation protocol takes approximately 48 h and includes stimulating cells synchronized in G₀/G₁ phase of the cell cycle with agonists, labeling cells with [³H]thymidine and examining levels of [³H]thymidine incorporation by scintillation counting. Although using radiolabeled [³H]thymidine incorporation is a limitation, the greatest benefit of the assay is providing reliable and statistically significant data.