RESUMO
Fish germ cell transplantation presents several important potential applications for aquaculture, including the preservation of germplasm from endangered fish species with high genetic and commercial values. Using this technique in studies developed in our laboratory with adult male Nile tilapias (Oreochromis niloticus), all the necessary procedures were successfully established, allowing the production of functional sperm and healthy progeny approximately 2months after allogeneic transplantation. In the present study, we evaluated the viability of the adult Nile tilapia testis to generate sperm after xenogeneic transplant of germ cells from sexually mature Jundia catfish (Rhamdia quelen) that belong to a different taxonomic order. Therefore, in order to investigate at different time-periods post-transplantation, the presence and development of donor PKH26 labeled catfish germ cells were followed in the tilapia seminiferous tubules. From 7 to 20days post-transplantation, only PKH26 labeled spermatogonia were observed, whereas spermatocytes at different stages of development were found at 70days. Germ cell transplantation success and progression of spermatogenesis were indicated by the presence of labeled PKH26 spermatids and sperm on days 90 and 120 post-transplantation, respectively. Confirming the presence of the catfish genetic material in the tilapia testis, all recipient tilapias evaluated (n=8) showed the genetic markers evaluated. Therefore, we demonstrated for the first time that the adult Nile tilapia testis offers the functional conditions for development of spermatogenesis with sperm production from a fish species belonging to a different order, which provides an important new venue for aquaculture advancement.
Assuntos
Peixes-Gato/metabolismo , Transplante de Células , Xenoenxertos/citologia , Espermatozoides/citologia , Testículo/citologia , Tilápia/metabolismo , Transplante Heterólogo , Animais , Aquicultura/métodos , Peixes-Gato/genética , Conservação dos Recursos Naturais/métodos , Espécies em Perigo de Extinção , Xenoenxertos/crescimento & desenvolvimento , Masculino , Túbulos Seminíferos/citologia , Espermátides/citologia , Espermátides/crescimento & desenvolvimento , Espermátides/metabolismo , Espermatócitos/citologia , Espermatócitos/crescimento & desenvolvimento , Espermatócitos/metabolismo , Espermatogênese , Espermatogônias/citologia , Espermatogônias/crescimento & desenvolvimento , Espermatogônias/metabolismo , Espermatozoides/crescimento & desenvolvimento , Espermatozoides/metabolismo , Testículo/fisiologia , Tilápia/genéticaRESUMO
Similar to mammals, spermatogenesis in fish is initiated by spermatogonial stem cells (SSCs) which either self-renew or gradually differentiate to produce mature sperm. SSCs are located in a particular testis microenvironment called SSC ni che, formed by Sertoli and peritubular myoid cells, the basement membrane and other cellular components/factors from the intertubular compartment that regulate SSCs maintenance and fate. Considering the great variation in testis structure/arrangemen t across fish species, the study of the niche components is crucial to understand SSCs physiology. Additionally, the germ cell transplantation technique, which has been applied to fish in the last decade, is a unique approach to elucidating important functional aspects of SSCs biology such as: (i) the capacity of SSCs to colonize the testis of recipient species (syngeneic and xenogeneic transplantation) giving rise to donor sperm; (ii) the plasticity of these cells, considering that spermatogonia and oogonia can be derived from SSCs collected from the opposite sex; and (iii) the possibility of genetically manipulating SSCs before transplantation to produce transgenic fish. However, fish SSC isolation and characterization has been lim ited so far by the lack of specific molecular markers fo r these cells. Therefore, various research groups are currently investigating specific SSCs markers and, up to date, few proteins have been identified in different spermatogonial populations from distinct fish species (e.g. Notch1, Ly75, Plzf, Oct-4, SGSA -1). Furthermore, the development of a fish SSC culture system would allow the investigation of important regulatory aspects of the SSC physiology in well-defined conditions as well as to in vitro amplify these rare cells. Overall, the study of SSC physiology, niche and transplantation in fish has opened up new scenarios for the development of aquaculture and reproductive biotechnologies such as germplasm conservation of endangered or commercially important species and the possibility of generating transgenic fish.(AU)
Assuntos
Animais , Espermatogênese/fisiologia , Espermatozoides/citologia , Fisiologia , Aquicultura/tendências , Peixes/classificação , Biotecnologia/métodosRESUMO
Similar to mammals, spermatogenesis in fish is initiated by spermatogonial stem cells (SSCs) which either self-renew or gradually differentiate to produce mature sperm. SSCs are located in a particular testis microenvironment called SSC ni che, formed by Sertoli and peritubular myoid cells, the basement membrane and other cellular components/factors from the intertubular compartment that regulate SSCs maintenance and fate. Considering the great variation in testis structure/arrangemen t across fish species, the study of the niche components is crucial to understand SSCs physiology. Additionally, the germ cell transplantation technique, which has been applied to fish in the last decade, is a unique approach to elucidating important functional aspects of SSCs biology such as: (i) the capacity of SSCs to colonize the testis of recipient species (syngeneic and xenogeneic transplantation) giving rise to donor sperm; (ii) the plasticity of these cells, considering that spermatogonia and oogonia can be derived from SSCs collected from the opposite sex; and (iii) the possibility of genetically manipulating SSCs before transplantation to produce transgenic fish. However, fish SSC isolation and characterization has been lim ited so far by the lack of specific molecular markers fo r these cells. Therefore, various research groups are currently investigating specific SSCs markers and, up to date, few proteins have been identified in different spermatogonial populations from distinct fish species (e.g. Notch1, Ly75, Plzf, Oct-4, SGSA -1). Furthermore, the development of a fish SSC culture system would allow the investigation of important regulatory aspects of the SSC physiology in well-defined conditions as well as to in vitro amplify these rare cells. Overall, the study of SSC physiology, niche and transplantation in fish has opened up new scenarios for the development of aquaculture and reproductive biotechnologies such as germplasm conservation of endangered or commercially important species and the possibility of generating transgenic fish.