Idade da doadora e diferentes gêneros receptores: respostas ao xenotransplante ovariano ovino por longo período de cultivo

Abstract

The stock of primordial and primary follicles in fetal ovaries represents an untapped potential that can be cultivated for purposes of reproduction, preservation or research. Additionally, the use of male immunodeficient receptors in the ovarian xenograft provides more opportunity to use genetic material that could be lost. Thus, the objective was to evaluate the development and viability of ovarian ovine tissue, in the fetal phase and in the prepubertal phase, freshly grafted, in different strains and sex of immunosuppressed mice. For the first experiment, ovaries from fetal sheep (100-140 days old) were harvested after slaughtering their mothers, divided into small fragments (1 mm3 ) that were destined for control evaluation and fresh xenotransplantation. Five C57BL/6 SCID strain recipients were used for xenotransplantation. Five days after the surgical procedure, the recipient mice were subjected to vaginal lavage for 60 days. At the end of this period, they were euthanized and the grafts were collected for macro and microscopic evaluations. It was observed that in 80% of the receiving females the cytological pattern of the vaginal lavage alternated between diestrus-proestrus-diestrus, with the estrus and metestrus phases not being observed during the experimental period. Histological analysis showed that neovascularization occurred in 80% of the recovered tissues. Pre-antral and antral follicles (smaller) and without morphological changes were also observed, however, antral follicles larger than 1 mm were not obtained. Corpus luteum was also not seen. In the second experiment, ovarian fragments (1 mm3 ) from young sheep were xenotransplanted fresh into male recipients of the C57BL/6 SCID (n = 5) and BALB/c Nude (n = 5) lines. After 65 days of xenograft, the animals were euthanized and the grafts were evaluated for macroscopic and microscopic characteristics and oocyte development in vitro. It was observed in the tissues recovered from animals of the C57BL / 6 SCID strain a high follicular consumption. Of the remaining morphologically normal follicles, most were primordial. Additionally, areas with scar tissue similar to the corpus albicans were also found. In grafts recovered from animals of the BALB/c Nude strain, moderate follicular consumption was observed, with a low rate of normal primordial and primary follicles and a high proportion of primordial atretic follicles. Additionally, an oocyte was recovered, which was subjected to maturation, fertilization and in vitro culture without, however, showing embryonic development. Considering that donors of the same species were used, it is concluded that the age of the donor, the recipient species and the period for the collection of ovarian tissue must be adapted for better results.