Background: Neoplasia can results from a lack of cell elimination by apoptosis. In order to determine if mechanisms controlling apoptosis are disturbed during neoplastic transformation in a model of murine radio-induced thymic lymphomas, we have assessed the kinetics of p53, Bax and Bcl-2 in situ expression after induction of thymic apoptosis by irradiation or glucocorticoids at first in normal mice.
Materials and methods: TUNEL method was used for in situ detection of apoptosis and protein expression was determined by indirect immunohistochemistry.
Results: After hydrocortisone injection, levels of p53 and Bax, but not Bcl-2, expression were raised. A whole body sublethal irradiation led to an increase of p53 and Bcl-2, but not Bax, expression.
Conclusions: This is the first in vivo report of in situ protein expression in the thymus after apoptogenic treatments of mice. The results suggest that Bax could be involved in glucocorticoid-mediated apoptosis. The increased levels of Bcl-2 expression are discussed.