Age dependence of murine spermatogenesis.

The dependence of spermatogenesis function on murine age shall be investigated. Thus, testicular samples of at least 10 NMRI mice per group aged 0 to 26 months are analysed by flow cytometry after staining the DNA with DAPI. The aim of this study is to be able to account for the influence of age on mice. There are no changes in spermatogenesis in mice aged 11 weeks up to 16 months with respect to testis weight and to the frequency of different testicular cell types. From 16 months onwards, there is a tendency to a reduced spermatogenesis function: The frequency of round spermatids is decreased. In addition, there is an increased chromatin dispersion in elongated spermatids with age. Thus, older mice (> 16 months) should not be used for experiments e.g. on radiation and drug effects any more. The frequency of abnormal diploid spermatozoa does not increase with age.