The effects of corticosteroids on the healing of tracheal anastomoses in a rat model

The deleterious effects of corticosteroids on anastomotic healing have been widely demonstrated in various tissues. This study is designed to investigate the effects of corticosteroids on the healing of tracheal anastomoses. Forty-two adult female Wistar rats, randomly divided into five groups, underwent tracheal transection and primary anastomoses. The groups were assigned as follows: Group I, sham, ( N= 6); Group II, control, ( N= 6); Group III, dexamethasone, 0.1 mg kg (-1) per day, intramuscularly for a week ( N= 10); Group IV, dexamethasone, 1 mg kg (-1) per day, intramuscularly for a week (N= 10); Group V, dexamethasone, 6 mg kg (-1) intramuscularly as a single dose ( N= 10). After 7 days, anastomotic healing was assessed by measurement of bursting pressure and hydroxyproline content. Histological examination was performed according to the modified Ehrlich/Hunt scale. The bursting pressure was significantly decreased in Group III and Group IV when compared to the control group (P0.0001 for both groups). There was also significance between the bursting pressures of Group III and Group IV (P0.01). However, the difference failed to reach significance between Group V and the control group. The reduction of bursting pressure was not reflected in diminished hydroxyproline content. The hydroxyproline content of the study groups (GIII, GIV and GV) were not statistically different compared with the control group. Except for inflammatory cell infiltration, histological parameters including epithelial regeneration, fibroblast proliferation, collagen content, and angiogenesis also demonstrated significant differences among the groups (P0.05). The present study demonstrates that daily administration of dexamethasone for a week significantly impairs the healing of tracheal anastomoses in a dose-dependent manner while a single-dose postoperatively does not affect the healing process.