STUDIES ON CRYOPRESERVATION AND TRANSPLANTATION OF THE MALE GERM CELL IN AMERICAN SHAD (ALOSA SAPIDISSIMA)

Germ cells, different from somatic cells, carry the hereditary information and can transmit it to next generation. The germ cells cryopreservation and culture are the key techniques for cell engineer breeding and genetic resource preservation. This study investigated the effects of cryopreservation of the testicular blocks or dissociated cells on the viability of male germ cells of American shad after 250 days using Hochest33342/Propidium Iodide (PI) staining. The results showed that the overall viability of germ cells from the testis blocks cryopreservation was higher than that of dissociated cells cryopreservation, suggesting that the tissue frozen could efficiently cryopreserve the germ cells at different stages in American shad. Moreover, the thawed germ cells of American shad were stained with PKH26 before transplantation into newly-hatched zebrafish fries (1 days post hatching). At the 5^th day post transplantation, the donor cells were still detected in some recipients and some donor cells were co-localized with the endogenous PGCs of recipient, implying that the germ cells of American shad after a long-term cryopreservation still possess the properties of germ cells and could integrate to the genital ridge of zebrafish host. The findings of this study provide technological and theoretical basis for further investigations on germ cell development, culture and genetic resource preservation in American shad or other anadromous fish in wild field.