CHANGES OF COLON EPITHELIUM PROLIFERATION DUE TO INDIVIDUAL AGING WITH CYCLIN PROLIFERATING CELL NUCLEAR ANTIGEN (PCNA CYCLIN) IMMUNOSTAINING COMPARED TO [H-3] THYMIDINE AUTORADIOGRAPHY

We report a change in the proliferative activity of mouse colonic epit helium due to development and aging. In order to measure the prolifera tive activity, colonic epithelium was immunostained for cyclin prolife rating cell nuclear antigen (PCNA/cyclin), which appears from the GI t o the S phase of the cell cycle, and compared with labeling obtained b y [H-3]-thymidine radioautography. Litter mice of six age groups from the fetal period (embryonic day 19), newborn period (postnatal day 1), suckling period (postnatal day 5), weaning period (postnatal dy 21), adult period (2 month old) to the senescent period (11 month old) were examined by immunohistochemistry. The descending colons were fixed in methacarn (method-Carnoy) and embedded in paraffin. Sections were sta ined for PCNA/cyclin activity using 19A2 monoclonal antibody and the a vidin-biotin peroxidase complex (ABC) technique. For radioautography, litter mice of nine age groups using in vivo intraperitoneal administr ation of [H-3]-thymidine. The labeling indices of colonic epithelial c ells in the proliferative zone were then analyzed and compared between the two investigative methods. Our results show that the proliferativ e activity of mice colon was high in the fetal and newborn periods and almost constant from the suckling period to senescence, as demonstrat ed by both PCNA/cyclin immunohistochemistry and [H-3]thymidine radioau tography. The labeling index seen by PCNA/cyclin immunohistochemistry was, however, higher than that seen by [H-3]-thymidine radioautography .