Expression and distribution of topoisomeraseII in apoptotic cells

Objectives:To study the expression of bcl-2, topoisomeraseⅡ( TopoⅡ) and Ki-67 in lymph follicles of tonsil, and to explore their roles in the regulation of apoptosis. Methods:TUNEL method and immunohistochemistry(s-p method) were used to observe the expression of bcl-2, Ki-67 and TopooⅡin lymph follicles in 23 cases of excised tissues(also including chronic tonsillitis). Results:TUNEL revealed that apoptotic cells were mostly concentrated in the germinal center. Immunohistochemistry found that in all 23 cases bcl-2 positive expressed in cells located in the mantle zone lymphocytes which surround germinal centers but not in the germinal centers, and the TopooⅡwas expressed concentrically in the dark zones and the basal light zones but infrequently in the mantle zones and its distribution was similar to Ki-67 and apoptosis with TUNEL. Conclusions: bcl-2 showed expression and TopooⅡexhibits active immunoactivity in lymph follicles in which apoptosis is active. bcl-2 inhibits apoptosis and TopooⅡhas germane relationship to apoptosis.