The Length of the Spermatogenic Cycle Is Conserved in Porcine and Ovine Testis Xenografts

Avelar, Gleide Fernandes de; Rathi, Rahul; França, Luiz R.; Dobrinski, Ina

doi:10.2164/jandrol.05143

Cited by 85 publications

(41 citation statements)

References 25 publications

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“…The timing of appearance of spermatocytes or spermatozoa in the xenografts was similar to those observed in developing boars [33,34]. Zeng et al [35] demonstrated that the length of the spematogenic cycle in porcine xenografts implanted into immunodeficient mice was about 9 days, which is similar to that observed in boars [33,36]. However, spermatogenesis in the grafted tissues did not reach the quantitatively normal levels observed in young adult boars.…”

Section: Discussionsupporting

confidence: 56%

Endocrine Status and Development of Porcine Testicular Tissues in Host Mice

Kaneko

Kikuchi

Nakai

et al. 2008

Journal of Reproduction and Development

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Abstract. Clarification of the endocrine status of host mice provides us with basic knowledge with which we can manipulate the growth and function of xenografted testicular tissues. We investigated the hormonal profiles of castrated mice grafted with porcine immature testicular tissues from 30 to 210 or more days after grafting (day 0= castration and grafting). The serum follicle stimulating hormone (FSH) concentrations of the host mice declined (P<0.05) from day 60 compared with those of the castrated, ungrafted mice. The serum inhibin and testosterone levels were higher (P<0.05) than those in the castrated, ungrafted mice from days 30 and 90 days, respectively. The inhibin levels further increased (P<0.05) from day 90, during which time the levels were higher (P<0.05) than those in the intact male mice. In the grafts, formation of lumens occurred in the seminiferous cords on day 90 and spermatozoa appeared in the lumens from day 120. However, spermatogenesis in the grafts did not reach the qualitatively normal levels observed in adult boars. The intensity of the immune reaction to inhibin α subunits in the Sertoli cells of the grafts decreased with differentiation of the seminiferous tubules. The present findings indicate that a feedback loop was established between the mouse hypothalamo-pituitary axis and the grafted porcine tissues from 60 days post-grafting. The results also indicate that the serum inhibin levels in the host mice remained high even after the appearance of lumens in the seminiferous tubules of the grafted tissues; this is strikingly different to the situation in normal male animals, in which the serum inhibin levels decline at around the time of tubular differentiation. The lack of efferent ducts in the tubules of the grafted tissues probably caused the accumulation of inhibin to be released into the lumens, resulting in high concentrations of circulating inhibin. These high levels of inhibin may directly affect spermatogenic activity and suppress FSH secretion. [6], and then xenografted into immunodeficient mice. Successful recovery of spermatozoa from the grafts has been proven in several species (pigs [3], cats [5] and rhesus monkeys [6]). However, no progeny have been obtained from spermatozoa isolated from the xenografts of these animals. Clarification of the endocrine status of the host mouse would likely help us to improve spermatogenesis in grafted testicular tissues, since development of the testis is controlled by the balance between the pituitary hormones, which stimulate testicular function, and testicular hormones, which alter the secretion of the pituitary hormones [7]. To date, the hormonal characteristics of host mice have been elucidated only after grafting of murine testicular tissues [8]; the study indicated that a feedback loop was established between the graft and the host's hypothalamo-pituitary 2 weeks after grafting, when the graft acquired the ability to produce testosterone. However, the time required for testicular maturation is much longer in large animals, such ...

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Section: Discussionsupporting

confidence: 56%

Endocrine Status and Development of Porcine Testicular Tissues in Host Mice

Kaneko

Kikuchi

Nakai

et al. 2008

Journal of Reproduction and Development

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“…Table 2 shows that the percentage of xenografts recovered from recipient mice decreased as donor age increased and that the percentage of the xenografts containing germ cells at different stages of spermatogenesis varied with both donor age and the retrieval time points. For the 8-and 9-16-week-old donor age groups in our study, we had a percentage recovery rate very similar to that reported for other species (Rathi et al 2005;Zeng et al 2006).…”

Section: Discussionsupporting

confidence: 87%

“…Spermatocytes were observed in approximately one-third of the xenografts 10 weeks after the procedure in the 8-week-old donor group, as opposed to typically appearing at age 5-6 months. This has been noted by others (Oatley et al 2005;Rathi et al 2005;Zeng et al 2006) working not only with species in which sperm production is accelerated, but also species in which sperm production occurs at approximately the same time as in age-matched control testes. The most likely explanation for this early onset of meiosis is that the xenograft tissue is suddenly exposed to an adult endocrine profile in the recipient mouse and the germ cells are able to respond (Honaramooz et al 2002;Schlatt et al 2003;Rathi et al 2005).…”

Section: Discussionmentioning

confidence: 58%

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

Kim

Selvaraj

Pukazhenthi

et al. 2007

Reprod. Fertil. Dev.

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Abstract. 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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“…Therefore, in large domestic animals, testicular xenografting into under skin of back of immunodeficient animals such as nude mice or SKID mice has been conducted. To date, sperm have been obtained from testicular grafts of several species after ectopic xenotransplantation (pig [52][53][54]; goat [52]; cat [55]; and rhesus monkey [56]). In our study [57], we obtained testicular tissues from 5 days old piglet ( Fig.…”

Section: Icsi With Sperm Grown In Testicular Tissues Xenografted Intomentioning

confidence: 99%

Factors Affecting Fertilization and Embryonic Development During Intracytoplasmic Sperm Injection in Pigs

Nakai

Kashiwazaki

Ito

et al. 2011

Journal of Reproduction and Development

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Abstract. In intracytoplasmic sperm injection (ICSI) technique, a sperm was injected into ooplasm directly using a glass pipette. The fertilization physiology in ICSI is considered quite different from that of the natural fertilization. The different mechanisms for fertilization may be the causes of various results in ICSI. In this paper, we focus on the state of sperm membranes, nuclear or DNA integrity during ICSI procedure and discuss the influence of these factors on fertilization and embryonic development. We also introduce some examples in application of ICSI for new technologies in pigs. Key words: Embryonic development, Fertilization, ICSI, Pig (J. Reprod. Dev. 57: [183][184][185][186][187] 2011) uring natural fertilization, sperm needs several steps; e.g., attachment to zona pellucida, penetration through zona pellucida with releasing of acrosomal enzymes from acrosomal caps, fusion of sperm membrane with oolemma, decondensation and recondensation of sperm nucleus after incorporation into ooplasm, and finally formation of male pronucleus [1]. Therefore, if sperm have no or faint motility, such sperm cannot reach and penetrate an oocyte resulting in a failure of fertilization. On the other hand, by intracytoplasmic sperm injection (ICSI), a whole spermatozoon or a sperm nucleus can be deposited directly into ooplasm by a glass pipette. Therefore, ICSI technique enables production of fertilized oocytes even if spermatozoa lack their competence for physiological fertilization.As mentioned above, spermatozoa can be brought into ooplasm by ICSI without any physiological events. In other words, spermatozoa bring intact membrane and acrosomal enzymes into ooplasm. Furthermore, there causes a possibility that sperm with some abnormalities may participate in fertilization and further embryonic development resulting in offspring, because spermatozoa are injected into ooplasm by artificial procedure without physiological selection processes. In this paper, we discuss about sperm factors which may affect the completion of fertilization by ICSI in pigs as a model for large domestic animals. Furthermore, recently the combination of ICSI and some other techniques has been expected as novel procedure for conserving male genetic resource. For completion of this technology, ICSI is the most essential procedure. We introduced the recent results in our laboratory for these new approaches. Carrying of Acrosomal Membrane and Their Enzymes Into OoplasmAt the first step of fertilization, sperm have to travel through the cumulus cells and their matrix and then penetrate the zona pellucida. In natural fertilization, sperm release acrosomal enzymes from acrosome cap (acrosome reaction), move forward by a driving force of sperm tail. Therefore, after the penetration of zona pellucida, sperm without outer-acrosomal membrane and acrosomal enzymes reach to the oolemma. However, by ICSI, sperm do not lose those constructions and those with their complete form are injected into ooplasm. Therefore, it is important to discuss the effe...

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The Length of the Spermatogenic Cycle Is Conserved in Porcine and Ovine Testis Xenografts

Cited by 85 publications

References 25 publications

Endocrine Status and Development of Porcine Testicular Tissues in Host Mice

Endocrine Status and Development of Porcine Testicular Tissues in Host Mice

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

Factors Affecting Fertilization and Embryonic Development During Intracytoplasmic Sperm Injection in Pigs

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