Long-term follow-up of tracheal cartilage growth promotion by intratracheal injection of basic fibroblast growth factor.

BACKGROUND: Intratracheal injection of basic fibroblast growth factor (b-FGF) has been shown to enlarge the tracheal lumen 4 weeks after treatment. The objective of this study was to investigate the long-term effect of tracheal cartilage growth promotion by intratracheal injection of b-FGF. MATERIALS AND METHODS: New Zealand white rabbits were classified into four groups to receive either distilled water alone (Group 1; n = 16; control), 40 µg (Group 2; n = 10), 100 µg (Group 3; n = 13), or 200 µg (Group 4; n = 16) of b-FGF dissolved in water. The treatment was injected into the posterior wall of the cervical trachea using a tracheoscope. The animals were sacrificed 4 or 12 weeks later. RESULTS: Four weeks after treatment, the mean luminal areas of tracheas for Groups 1, 2, 3, and 4 were 27.2, 25.6, 32.2, and 36.2 mm2, respectively. At 12 weeks, these were 29.3, 37.9, 42.5, and 56.0 mm2, respectively. The levels of glycosaminoglycan at 12 weeks were 93.9, 152.5, 123.2, and 210.6 µg/mg, respectively. At 12 weeks, the levels of type II collagen were 77.2, 133.1, 99.2, and 148.9 µg/mg, respectively. CONCLUSION: Twelve weeks after a single injection of b-FGF, the mean luminal area of the trachea continued to increase.