Impact of Ionizing Treatment on the Nuclear Structure of Human Spermatozoa.

Differentiated thyroid cancer is the third cause of cancer in young men of childbearing age. Its treatment by irradiation with Radioactive Iodine 131 therapy (RAT) could alter spermatogenesis and result in azoospermia and permanent infertility. A preventive gametes cryopreservation was recommended before RAT, but without mentioning a period of teratogenic risk transmissible to the offspring. To date, RAT impact on human sperm nucleus is poorly known or even unknown, notably on telomere length. Our objective is to define RAT effects on human sperm nucleus by in vitro irradiation exposure of human spermatozoa to mimicking that of the gonads in the context of irradiation with iodine131 used for thyroid cancer. We will analyze standard sperm parameters, major DNA alterations and telomere length using molecular and cellular assays. Nucleus morphology and chromatin organization will also be analyzed using 3D bio-imaging. This study will permit to optimize the indications for the preservation of fertility.