Effects of environmental stress on tissue survival and neutrophil recruitment in surgical skin flaps in relation to plasma corticosterone levels in the rat

Abstract

Objective: Because glucocorticoid treatment can improve the survival of surgical skin flaps, we examined the influence of environmental stress on skin flap survival in the rat.¶Material: Female Sprague-Dawley rats.¶Treatment: Dexamethasone (1 mg/kg i.p.).¶Methods: A standardized dorsal skin flap was raised and sutured back into position, and six days later the percentage of flap survival was assessed. Corticosterone in rat plasma was measured using radioimmuno assay, and skin flap myeloperoxidase accumulation (reflecting neutrophil recruitment) was determined spectrophotometrically.¶Results: Skin flap survival decreased gradually during a 10 day acclimatization period after transportation of the animals from the supplier, and plasma corticosterone levels were increased during the first 5 days of acclimatization compared to day 7 and 10. Dexamethasone treatment of rats accustomed to their new environment for 10 days increased flap survival to a level close to that observed in animals operated at day 1 after arrival. Flap surgery induced pronounced neutrophil recruitment into flap tissue, and this cell accumulation was greatly reduced in both the dexamethasone treated rats and in rats with elevated corticosterone levels.¶Conclusions: Skin flap survival in rats exposed to environmental stress may be significantly increased as compared to animals accustomed to their new environment for one week, possibly as a consequence of anti-inflammatory actions exerted by stress-induced elevations in plasma corticosterone. These findings emphasize the importance of strictly controlling environmental stress factors in studies of inflammation and tissue damage after surgical skin trauma.