Effect of donor age on success of spermatogenesis in feline testis xenografts

Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
Reproduction Fertility and Development (Impact Factor: 2.4). 02/2007; 19(7):869-76. DOI: 10.1071/RD07056
Source: PubMed


Ectopic xenografting of 'donor' feline testicular tissue into a 'recipient' immunodeficient mouse is a promising tool to preserve the male genome from genetically valuable felids. To define parameters under which the technique can succeed, we compared the effect of donor age on xenograft spermatogenesis among four age groups of domestic cats (Felis catus; age range 8 weeks to 15 months). In all cases, fresh tissue was grafted into castrated mice and collected 10, 30 and 50 weeks later. The percentage of xenografts recovered decreased as donor age increased. Mature testicular spermatozoa were observed in xenografts from the 8 and 9-16 week age groups; only a single 7-month-old donor produced elongating spermatids and xenografts from donors >/= 8 months of age degenerated. Seminal vesicle weight, an indicator of bioactive testosterone, was not significantly different between donors aged 8 weeks to 7 months and controls, suggesting that xenograft Leydig cells were ultimately functional even in the 5-7 month age group. Regardless of donor age, production of mature spermatozoa from xenografts was markedly delayed compared with controls. Comparison of xenografts that produced sperm with normal controls revealed a decrease in tubule cross-sections having post-meiotic germ cells. Together, these results indicate that the maximum practical donor age was just before the onset of puberty and that even successful xenografts had abnormalities in spermatogenesis.

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    • "Completion of spermatogenesis was first described by Honaramooz et al. [1] in testicular tissue of neonatal pigs and goats that had been grafted into nude mice. Since this pioneering study, fresh testicular tissues prepared from neonatal donors of many species have been grafted into immunodeficient mice, and in most cases the xenografts have initiated spermatogenesis, reaching the stage of elongated spermatids (primate [2], cattle [3]–[6], horse [7]) or sperm (primate [8], pig [1], , cat [14], [15], dog [16], rabbit [17]). Although limited so far to rabbit [17] or pig [13], intracytoplasmic sperm injection (ICSI) using xenogeneic sperm has been used successfully to producing live offspring. "
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    ABSTRACT: Cryopreservation of immature testicular tissues is essential for increasing the possibilities of offspring generation by testicular xenografting for agricultural or medical purposes. However, successful production of offspring from the sperm involved has never been reported previously. In the present study, therefore, using intracytoplasmic sperm injection (ICSI), we examined whether xenogeneic sperm obtained from immature pig testicular tissue after cryopreservation would have the capacity to produce live piglets. Testicular fragments from 9- to 11-day-old piglets were vitrified after 10- or 20-min immersion in vitrification solution containing ethylene glycol (EG), polyvinyl pyrrolidone (PVP) and trehalose as cryoprotectants, and then stored in liquid nitrogen for more than 140 days. Thirty nude mice were assigned to each immersion-time group. Testicular fragments were transplanted under the back skin of castrated mice immediately after warming and removal of the cryoprotectants. Blood and testicular grafts were then recovered from the recipient mice on days 60, 120, 180 and 230-350 (day 0 = grafting). Histological assessment of the testicular grafts and analyses of inhibin and testosterone production revealed no significant differences between the two immersion-time groups, indicating equal growth activity of the cryopreserved tissues. A single sperm obtained from a mouse in each group on day 230-350 was injected into an in vitro-matured porcine oocyte, and then the ICSI oocytes were transferred to the oviducts of estrus-synchronized recipient gilts. One out of 4 gilts that had received oocytes fertilized using sperm from the 10-min immersion group delivered 2 live piglets, and one of another 4 gilts from the 20-min group delivered 4 live piglets. Thus, we have successfully generated porcine offspring utilizing sperm from immature testicular tissues after cryopreservation and transplantation into nude mice. The present model using pigs will be applicable to many large animals, since pigs are phylogenetically distant from the murine recipients.
    PLoS ONE 07/2013; 8(7):e70989. DOI:10.1371/journal.pone.0070989 · 3.23 Impact Factor
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    • "However, the efficiency of spermatogenesis in xenografts differs among species, with the bull [37-39], cats [35,40], and dogs [36] being less efficient. One common finding across species is that if the donor testis tissue has germ cells actively undergoing meiosis (as in puberty or adulthood), then the xenografts lose the ability to support spermatogenesis [40,41]. The fertilizing ability of graft-derived sperm has been verified by the production of viable offspring in allografted mouse [42] and xenografted rabbit [31] and pig [43]. "
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    ABSTRACT: The stem cell field in veterinary medicine continues to evolve rapidly both experimentally and clinically. Stem cells are most commonly used in clinical veterinary medicine in therapeutic applications for the treatment of musculoskeletal injuries in horses and dogs. New technologies of assisted reproduction are being developed to apply the properties of spermatogonial stem cells to preserve endangered animal species. The same methods can be used to generate transgenic animals for production of pharmaceuticals or for use as biomedical models. Small and large animal species serve as valuable models for preclinical evaluation of stem cell applications in human beings and in veterinary patients in areas such as spinal cord injury and myocardial infarction. However, these applications have not been implemented in the clinical treatment of veterinary patients. Reviews on the use of animal models for stem cell research have been published recently. Therefore, in this review, animal model research will be reviewed only in the context of supporting the current clinical application of stem cells in veterinary medicine.
    Stem Cell Research & Therapy 02/2011; 2(1):9. DOI:10.1186/scrt50 · 3.37 Impact Factor
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    • "Testis tissue xenografting has been successfully evaluated in numerous species, including cattle (Oatley et al, 2005; Rathi et al, 2005; Schmidt et al, 2006). These studies have shown that viability and differentiation of the grafted tissue are inversely related with the age and developmental stage of the donor (Schlatt et al, 2002; Rathi et al, 2006; Kim et al, 2007; Arregui et al, 2008b). Thus, testes from immature individuals are mainly selected as a source of tissue, which basically allows recapitulation of the entire postnatal period. "
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    ABSTRACT: Testis tissue xenografting represents a versatile model to study testis biology, and to preserve fertility in immature animals. To evaluate whether bovine fetal testes can mature when grafted into mouse hosts, small fragments of testes from midgestation (125 to 145 days of gestation) bovine fetuses were grafted ectopically into immunodeficient castrated male mice. At grafting, donor tissue displayed the typical seminiferous cords composed of gonocytes and primitive Sertoli cells. At 5 or 10 months after grafting, weight of the seminal vesicles in recipient mice was indicative of production of bioactive testosterone by xenografts. Xenografts showed similar development regardless of donor age. At 5 months, tubule formation occurred but germ cell differentiation had not proceeded beyond the spermatogonia stage. At 10 months, an increase in tubule size was evident and pachytene spermatocytes were observed as the most advanced type of germ cells in the xenografts of 2 donors. The number of tubules with germ cells was reduced in xenografts compared to donor tissue, but at 10 months the number of germ cells per tubule was higher than in donors. Germ cell proliferation was similar in donor tissue and xenografts. However, Sertoli cells showed a higher proliferation rate in xenografts collected at 5 months than in donor fetal testes and xenografts collected at 10 months. Sertoli cells in xenografts showed a progressive but incomplete loss of expression of Müllerian inhibiting substance and weak androgen receptor expression, indicating an incomplete Sertoli cell maturation. In conclusion, fetal testis tissue developed partially, qualitatively similar to pubertal testes in situ.
    Journal of Andrology 10/2010; 32(3):271-81. DOI:10.2164/jandrol.110.010322 · 2.47 Impact Factor
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