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.