ULTRASTRUCTURE OF APOPTOTIC CELLS IN CHICKEN BURSA OF FABRICIUS AFTERGAMMA-IRRADIATION

Ultrastructure of irradiated lymphocytes in bursa of Fabricius was stu died. Twenty four chickens were irradiated by gamma rays al a total do se of irradiation 4,5 Gy and exposure time 12 min 24 s. Histological e xamination showed occurrence of pyknotic cells in bursa in experimenta l groups. Electron microscopy of the irradiated bursa revealed typical apoptotic morphology such as chromatin condensation, nuclear fragment ation formation of apoptotic bodies and phagocytosis of apoptotic cell s 6 hour after irradiation. The mitochondria appeared to be morphologi cally intact in the early stages of cell death. Phagocytosis is suppos ed to be done by resident macrophages which are mainly located in the medulla of the bursa Fabricii. Although bursa Fabricii like other lymp hoid organs has been known to be highly sensitive to irradiation, this work shows high scavenger capability of the mononuclear - phagocyte s ystem in bursa of Fabricii.