p53, Bax and Bcl-2 in vivo expression in the murine thymus after apoptogenic treatments.

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.