While adolescent and adult men have the option to cryopreserve sperm prior to chemotherapy or radiation in cancer treatment, this is not available to pre-pubertal boys. Researchers from the University of Pittsburgh School of Medicine and the Magee-Womens Research Institute write that several IVF centres worldwide are preserving testicular biopsies for these patients in anticipation that spermatogonial stem cells (SSCs) in the tissue can be used to achieve fertility in the future. In order to maximise the use of these tissues, the authors Valli-Pulaski et al, compared the cryopreservation of a cell suspension to an intact piece of tissue to discover the optimal cryopreservation method.

In the experiment the efficiency of each technique was analysed by immuno-cytochemistry for spermatogonia markers and human-to-nude mouse xenotransplantation. The average immuno-cytochemistry tested positive cells were highest in the fresh tissue; but from the cryopreserved groups, large tissue pieces and small tissue pieces had similar numbers of positive cells while cell suspension had the least positive cells and was significantly worse than cryopreserved intact tissue pieces. The authors conclude that based on their results, slow freezing of small piece of tissue is the most efficient technique to cryopreserve human testicular tissue. 

For further information
Optimising Cryopreservation of Human Testicular Tissues
Reproductive Biomedicine Online
Volume 37, Supplement 2, Page e4