Thermal Injury Induces Thymocyte Apoptosis in the Rat

Abstract

BACKGROUND: The thymus plays important roles in host defense, which may be impaired after burn injury. The effects of thermal injury on thymocytes were investigated in male Wistar rats. METHODS: Changes in thymus weight and content of glutathione and corticosterone were determined after burn injury. Apoptosis of thymocytes was detected by electrophoresis of DNA, and lymphocyte subsets were characterized by flow cytometry. The effects of adrenalectomy and the glucocorticoid receptor antagonist RU486 in burned animals were also studied. RESULTS: The weight of the thymus decreased progressively after burn injury, and this effect was accompanied by increases in the corticosterone concentration in plasma and the thymus and apoptosis of CD4+CD8+ thymocytes. Administration of RU486 or adrenalectomy inhibited burn-induced thymocyte apoptosis. CONCLUSION: Thermal injury increases the corticosterone concentration in plasma and the thymus and triggers thymocyte apoptosis.