PROLIFERATIVE ACTIVITY IN THE KIDNEYS OF AGING MICE EVALUATED BY PCNACYCLIN IMMUNOHISTOCHEMISTRY/

The change of proliferative activity in mouse kidney cortex cells due to aging was studied by PCNA/cyclin immunostaining. Mouse kidney tissu es of various ages: late fetal, newborn, suckling, weaning, adult and senescent were used for this experiment. Small pieces of kidney tissue s were fixed in methacarn solution and embedded in paraffin. Sections were stained with PCNA/cyclin monoclonal antibody. The reaction produc t for PCNA/cyclin was observed mainly on nuclei. The ratio of the PCNA /cyclin positive nuclei to the total number of nuclei were calculated. PCNA/cyclin positive ratios in glomeruli and uriniferous tubules in t he superficial layer were higher than those in the deep layer from lat e fetal period to suckling period. They decreased due to aging after b irth and became to nearly zero after weaning period.