Follicular development in ovarian autografts in the perimetrium and subcutaneous tissue of Balb-c mice

The aim of this study was to evaluate quantitatively and qualitatively follicles derived from autografts allocated in the subcutaneous tissue and perimetrium of mice. Twelve Balb-c female mice were randomly divided into three experimental groups with 4 animals in each group. Group I - control (non-transplanted animals), group II - animals that received the ovarian fragment in perimetrium, group III - animals that had the abdominal subcutaneous tissue as the receptor site. In transplanted animals, the left ovary was removed and used for other studies, while the cortex of the right ovary was fragmented and reimplanted according to the group description. Thirty days after surgery, mice were euthanized, transplants removed and histologically processed. The percentages of ovarian follicle categories (normal and atretic) were compared using the chi-square test (p < 0.05). Follicles were classified qualitatively (normal and atretic) and morphologically (primordial, transitional, primary, secondary, early antral, antral and preovulatory). No statistical difference was observed in the percentage of atretic follicles. The percentages of follicles in differente morphological categories did not vary either, except for pre-ovulatory follicles (group I = 1.4%, group II = 2.6%, group III = 11.3%). This difference was due to one of the subcutaneous transplants bearing only 1 follicle, which was preovulatory. In all groups, the largest population of normal follicles was constituted of preantral follicles (group I = 84.8%, group II = 83.5%, group III = 69.4%), with the highest percentage of primordial follicles (group I = 28.2%, group II = 31.3%, group III = 25.8%), primary (group I = 27.5%, group II = 26.1%, group III = 21.0%), followed by transitional (group I = 14.9%, group II = 17.4%, group III = 11.3 %) and secondary (group I = 14.2%, group II = 8.7%, group III = 11.3 %). This was likely due to their small size and simple structure; they also have lower metabolism favoring survival in ischemic environments. In addition, they are predominantly located to the periphery of the ovarian cortex favoring the benefit from revascularization after transplantation. Thus, we can conclude that ovarian autotransplantation maintains the viability of the organ, allowing survival and development of follicles to more advanced stages including preovulatory.