Ciliary Beat Frequency in Cultured Human Nasal Epithelial Cells

Abstract

This study aimed to determine the characteristics of ciliogenesis and the ciliary beat frequency (CBF) of cultured human nasal epithelial cells by means of an in vitro air-liquid interface (ALI) culture system. On the 14th, 21st, and 27th days of ALI culture, CBFs of cultured cells were measured with a video computerized analysis system, and the epithelial cell-collagen matrix complex was examined by scanning and transmission electron microscopy. Using a CBF distribution map, we calculated the proportion of ciliary beating area (CBA) on the cultured cells. On the 14th day, ciliated cells could be easily distinguished from other cells on scanning electron microscopy by their elongated cilia. Between the 14th and 27th days, the number of mature cilia increased, and after 27 days of air exposure, the cilia of each cell pointed to one direction. From the beginning of air-exposure culture until the 7th day, the number of secretory cells increased; however, from the 7th day to the 27th day, it decreased, and the number of ciliated cells increased. Total CBAs increased from the 7th day to the 21st day. The proportions of actively beating cells and the mean CBFs of beating cells among cultured epithelial cells increased with culture time. On the 21st day, the mean CBF of the cultured cells was similar to that of nasal ciliated cells in biopsy specimens (10.9 ± 0.5 Hz versus 11.4 ± 1.3 Hz), but until the 27th day, the CBF of cultured cells increased significantly (13.9 ± 0.8 Hz). It is suggested that there may be some difference in CBF between nasal epithelial cells submitted to biopsy and nasal epithelial cells cultured by the ALI culture system.