Nano-Scaffolds Enhance the Survival Rate of Immature Cryopreserved Testicular Tissue in Transplantation - Transgenic Mouse Model

Our proposal aims to the interdisciplinary field of biomedical engineering, including in vivo molecular imaging, tissue engineering and regenerative medicine by nano-based medicine as for our objectives are applied to design ideal 3D scaffolds with tissue engineering and nanotechnology to promote better survival of immature mouse testicular tissue grafts and tracked by in vivo bioluminescence Imaging longitudinally for the graft life span and quantity change. Prepubertal boys with cancer who are vulnerable to gonadotoxic chemotherapy or radiotherapy might become permanent sterile, even much weaker than female gonad. Due to unable to produce spermatogenesis for these cancer boys, they cannot benefit from sperm banking while spermatogonia banking. The alternative resorts may be subject to comprehensive frozen immature testicular tissue followed by transplantation as immature technique in vitro spermatogenesis and artificial gamete by iPS remain in its infancy. Immature testicular tissue cryopreservation for transplantation after treatment or in vivo spermatogenesis may restore their fertility in a more tangible fashion. Tissue engineering is a promising field that aims at fabricating biological alternatives for regenerating tissue and organ to restore function. Three-dimensional scaffolds mimicking the structure and biological function of native extracellular matrix are beneficial for cell and tissue growth. Meanwhile, they can also serve as the connection between the host and grafts. In our preliminary study, we have demonstrated that poly-L-lactide by micropore scaffolds could be used in fresh immature testicular tissue engineering in our transgenic mouse model. The preliminary poster earned the first place prize poster at the American Society of Reproductive Medicine annual meeting in 2013 to attract attention in a novel study trend. Grafts in scaffolds made by fine diameter fibers showed better regeneration and survival. This study pilots the way to the interdisciplinary strategy by the utility of scaffolds and in vivo optical imaging by bioluminescence imaging as a strong and real time tool to track the development of testicular grafts. That conformed the time of trend of 3Rs principle for animal study. In future studies we will modulate several variables of scaffolds, including biomaterial and fiber diameter to improve the efficiency and efficacy of cell regeneration after transplantation and well known cryobiology. In addition, cryoinjury could damage the frozen grafts, we will investigate the application of variable slow and ultra-rapid biotechnology on the cryopreservation of testicular tissue for immature male fertility preservation.