Assessment of ciliary phenotype in primary ciliary dyskinesia by micro-optical coherence tomography

Ciliary motion defects cause defective mucociliary transport (MCT) in primary ciliary dyskinesia (PCD). Current diagnostic tests do not assess how MCT is affected by perturbation of ciliary motion. In this study, we sought to use micro-optical coherence tomography (μOCT) to delineate the mechanistic basis of cilia motion defects of PCD genes by functional categorization of cilia motion. Tracheae from three PCD mouse models were analyzed using μOCT to characterize ciliary motion and measure MCT. We developed multiple measures of ciliary activity, integrated these measures, and quantified dyskinesia by the angular range of the cilia effective stroke (ARC). Ccdc39 mice, with a known severe PCD mutation of ciliary axonemal organization, had absent motile ciliary regions, resulting in abrogated MCT. In contrast, Dnah5 mice, with a missense mutation of the outer dynein arms, had reduced ciliary beat frequency (CBF) but preserved motile area and ciliary stroke, maintaining some MCT. Wdr69 PCD mice exhibited normal motile area and CBF and partially delayed MCT due to abnormalities of ciliary ARC. Visualization of ciliary motion using μOCT provides quantitative assessment of ciliary motion and MCT. Comprehensive ciliary motion investigation in situ classifies ciliary motion defects and quantifies their contribution to delayed mucociliary clearance.