Promoting successful healing of artificial trachea by intratracheal administration of basic fibroblast growth factor†

This study evaluated the effect of intratracheal administration of basic fibroblast growth factor (bFGF) on tracheal healing following implantation of a novel layered polyglycolic acid (PGA) material to replace a critical-size defect in rat trachea.

A critical-size defect in the rat cervical trachea was covered with PGA. Distilled water (DW) or 3.125, 6.25, 12.5 or 25 µg bFGF was administered into the trachea for 2 weeks (n = 6 for each of 5 groups). Regenerated areas of cilia, ciliary beat frequency and ciliary transport function (CTF) in the centre of the PGA were measured. To examine potential side effects of intratracheal administration of bFGF, the right lower lobe was pathologically evaluated.

All rats survived during the study period. Histological examination showed ciliated epithelization on the PGA material after 2 weeks. Bronchoscopy revealed stenosis due to granulation following administration of high concentrations of bFGF (12.5 and 25 µg). Compared with the DW group, groups administered 3.125, 6.25, 12.5 and 25 µg bFGF had significantly larger areas of regenerated cilia (15.2%, 27.0%, 41.3%, 33.1% and 31.0%, respectively; P = 0.00143), improved ciliary beat frequency (7.10, 8.18, 10.10, 9.50 and 9.50 Hz, respectively), and improved CTS (6.40, 9.54, 16.89, 16.41 and 14.29 µm/sec, respectively). Pathological examination of the right lower lobe revealed pulmonary fibrosis and hyperplasia with high concentrations of bFGF (12.5 and 25 µg).

Intratracheal administration of bFGF effectively promoted tracheal regeneration at an optimal dose of 6.25 µg following implantation of an artificial trachea.