Abstract
DNA degradation induced in the pancreatic tissues of rats by an administration of a diabetogenic dose of alloxan was studied with TUNEL assay. TUNEL−positive nuclei first appeared in pancreatic islet cells. Up to 3hr after an alloxan injection, the reaction products of TUNEL assay were found only in the nucleus of islet cells. However, 7hr after alloxan administration, some nuclei of cells in the exocrine portion, such as acinar cells, ductal epithelial cells, and some other cells were also labeled by TUNEL reaction in addition to the islet cells. Moreover, 7hr after alloxan administration, the TUNEL reaction products were found not only in the nucleus but also in the cytoplasm of insulin−producing cells injured by alloxan, as well as in the area containing amorphous substances that seemed to be the cell debris derived from destructed insulin−producing cells. The TUNEL−positive amorphous substances seemed to be finally absorbed by macrophages. These phenomena, the diffusion and mixing of the cytoplasmic and nuclear components of insulin−producing cells, are considered characteristics of islet cell necrosis induced by alloxan.
