Reproductive Technology

Generation of Normal Progeny by Intracytoplasmic Sperm Injection Following Grafting of Testicular Tissue from Cloned Mice that Died Postnatally

Abstract
Animal cloning by nuclear transfer has been successful in several species and was expected to become an alternative reproductive technique. Among the problems associated with this cloning technique are its low success rate and the high mortality of cloned animals even if they develop to term. Nuclear transfer has thus come to be considered too difficult to be applied as a reproductive technique. The transplantation of male germ cells or pieces of testicular tissue has enabled the induction of spermatogenesis from fetal or postnatal male mice. In this study, we examined whether functional male gametes could be obtained by the transplantation of pieces of testicular tissue from cloned mice that died immediately after birth with typical aberrant phenotypes such as large offspring syndrome. Donor testicular tissues were retrieved from cloned mice that died postnatally and transplanted into the testes of recipient nude mice. Two to three months after the transplantation, the grafted donor testicular tissue had grown in the host testis and histological analysis showed that spermatogenesis occurred within the graft. Intracytoplasmic sperm injection demonstrated that the testicular sperm generated in the grafted donor tissue were able to support full-term development of progeny. These results clearly showed that functional spermatogenesis could be induced by transplanting testicular tissue from cloned mice that died postnatally into recipient mice. The strategy presented here will be applicable to cloned animals of other species, as the xenografting of testicular tissue into mice has been previously demonstrated to be possible.

Key words: Assisted Reproductive Technology • Testis • Developmental biology • Sperm

This article has been cited by other articles:

				H. Ohta, Y. Sakaide, and T. Wakayama Generation of mice derived from embryonic stem cells using blastocysts of different developmental ages Reproduction, November 1, 2008; 136(5): 581 - 587. [Abstract] [Full Text] [PDF]

				H. Ohta, Y. Sakaide, K. Yamagata, and T. Wakayama Increasing the Cell Number of Host Tetraploid Embryos Can Improve the Production of Mice Derived from Embryonic Stem Cells Biol Reprod, September 1, 2008; 79(3): 486 - 492. [Abstract] [Full Text] [PDF]

				C. Wyns, M. Curaba, B. Martinez-Madrid, A. Van Langendonckt, W. Francois-Xavier, and J. Donnez Spermatogonial survival after cryopreservation and short-term orthotopic immature human cryptorchid testicular tissue grafting to immunodeficient mice Hum. Reprod., June 1, 2007; 22(6): 1603 - 1611. [Abstract] [Full Text] [PDF]

				T. Kohda, K. Inoue, N. Ogonuki, H. Miki, M. Naruse, T. Kaneko-Ishino, A. Ogura, and F. Ishino Variation in Gene Expression and Aberrantly Regulated Chromosome Regions in Cloned Mice Biol Reprod, December 1, 2005; 73(6): 1302 - 1311. [Abstract] [Full Text] [PDF]