Testicular damage during cryopreservation and transplantation.

Abstract

The aim of this study is to do a study of cryoinjury and ischaemic injury on testicular graft during cryopreservation and transplantation. According to time at 1, 3, 7 and 14days after transplantation, the grafts were collected for immunohistochemistry assay for CD34 (blood vessel marker), VEGF (neoangiogenesis marker), caspase-3 (apoptosis marker) MAGE-A4 (germ cell marker). A significant increase was observed in the density of VEGF-positive blood vessels on day 3, reached a peak on day 7. On post-transplant day 3, a sharp increase occurred in the rate of spermatogonia-expressing caspase-3 until the day 7. At 14th day after transplantation, the spermatogonia number per round tubule of nonfrozen grafts was 41±5.9% from that of fresh control tissues, while, in frozen-thawed grafts, the spermatogonia number per round tubule was 36.8±4.6% from that of fresh control tissues. In testicular grafts, angiogenesis initiated reperfusion from day 3, and the formation of new blood vessel generally is completed about 7days after transplantation. Angiogenesis in grafts after transplantation plays a crucial role in the restoration of function. Therefore, minimising ischaemic injury as well as improvement of cryopreservation protocols are needed to improve testicular graft after freezing, thawing and grafting.