The effects of granulocyte colony-stimulating factor on the healing of tracheal anastomosis following radiation therapy in rats.

OBJECTIVE This study evaluates the effects of granulocyte colony-stimulating factor on the healing of tracheal anastomosis following radiation therapy in rats. METHODS Fifty-six male Wistar rats were divided into four groups. Group 1 underwent tracheal anastomosis. Group 2 underwent radiation therapy followed by tracheal anastomosis. Group 3 underwent radiation therapy followed by tracheal anastomosis and received granulocyte colony-stimulating factor. Group 4 underwent sham radiation therapy followed by sham tracheal anastomosis. At 10 days following radiation therapy, the trachea was dissected for histopathological, mechanical and biochemical evaluation. RESULTS Median scores for inflammation were three points for Group 1, two points for Group 2, two points for Group 3 and one point for Group 4. Median scores for angiogenesis were four points for Group 1, two points for Group 2, three points for Group 3 and one point for Group 4. Median scores for connective tissue regeneration were four points for Group 1, two points for Group 2, three points for Group 3 and one point for Group 4. Median scores for epithelial regeneration were two points for Group 1, one point for Group 2, one point for Group 3 and one point for Group 4. Mean anastomotic bursting pressures were 853 mmHg for Group 1, 293 mmHg for Group 2, 417 mmHg for Group 3 and 966 mmHg for Group 4. Mean hydroxyproline concentrations were 159 microg/mg for Group 1, 177 microg/mg for Group 2, 120 microg/mg for Group 3 and 117 microg/mg for Group 4. CONCLUSIONS This study suggests that granulocyte colony-stimulating factor contributes to the healing of tracheal anastomosis following radiation therapy through improved connective tissue regeneration.