In vivo and in vitro development of Tibetan antelope(Pantholops hodgsonii)interspecific cloned embryos

The Tibetan antelope is endemic to the Tibetan Plateau,China,and is now considered an endangered species.As a possible rescue strategy,the development of embryos constructed by interspecies somatic cell nuclear transfer(iSCNT)was examined.Tibetan antelope fibroblast cells were transferred into enucleated bovine,ovine and caprine oocytes.These cloned embryos were then cultured in vitro or in the oviducts of intermediate animals.Less than 0.5%of the reconstructed antelope-bovine embryos cultured in vitro developed to the blastocyst stage.However,when the cloned antelope-bovine embryos were transferred to caprine oviducts,about 1.6%of the embryos developed to the blastocyst stage.In contrast,only 0.7%of the antelope-ovine embryos developed to the morula stage and none developed to blastocysts in ovine oviducts.The treatment of donor cells and bovine oocytes with trichostatin A did not improve the embryo development even when cultured in the oviducts of ovine and caprine.When the antelope-bovine embryos,constructed from oocytes treated with roscovitine or trichostatin A,were cultured in rabbit oviducts 2.3%and 14.3%developed to blastocysts,respectively.It is concluded that although some success was achieved with the protocols used,interspecies cloning of Tibetan antelope presents difficulties still to be overcome.The mechanisms resulting in the low embryo development need investigation and progress might require a deeper understanding of cellular reprogramming.