SPERMATID MICRONUCLEUS ANALYSIS OF AGING EFFECTS IN HAMSTERS

Spermatid micronuclei (MN) from Armenian hamsters in different age gro ups were compared with regard to frequencies and kinetochore status (p resence or absence) as determined with immunofluorescent staining. Six thousand cells analyzed from each of fifteen young animals (3 months) revealed a group mean frequency of 0.45 MN/1000 spermatids; kinetocho re staining was uniformly negative. Six thousand cells scored from eac h of fifteen older animals (2 years) revealed a group mean frequency o f 1.00 MN/1000 spermatids. Most of the MN in these animals were negati ve for kinetochore staining, although a significant representation of MN with positive kinetochore staining was also observed. The results i ndicate that frequencies of spermatid MN increase with advancing age, and suggest that the increase is due to significant elevations in both chromosome breakage and chromosome loss.