#335 : Ovarian Cortex with Higher Vascularization Density is Associated with Higher PTEN Expression After Transplantation on CAM

Abstract

Background and Aim: Before being applied on the clinical settings, the establishment of ovarian tissue cryopreservation and transplantation process should be optimum. The vascularization after transplant is depended on the ovarian tissue size, which influence the follicular recruitment. It may then affect the post-transplantation survival. Methods: On chorionic-allantoic membrane (CAM) of 8-days-old, fertilized eggs, goat ovarian tissue samples (Capra hircus) were split into pre- and post-transplantation groups. Each group was subsequently divided into 2.5×2.5×1, 5×5×1, and 10×10×1 mm size. Vascularization density and vascularization surface area was analysed and correlated with PTEN protein expressions. Results: Pre- and post-transplantation samples were taken from a total of 36 strips of ovarian tissue. The vascularization density was found to be the highest in the 2.5×2.5×1 mm transplantation samples compared to the pre-transplantation samples (9.54±3.2; 15.46±1.85; P<0,05). Meanwhile the vascularization surface area was also significantly higher after transplantation regardless the size of ovarian tissue (P<0,05). Interestingly, the vascularization surface area was observed to be significantly higher in the cortex area adhered to CAM compared to more distant than the CAM. To magnify the vascularization results, in the 2.5×2.5×1 mm transplantation sample, it was shown that the higher PTEN expression after transplantation. Concurrently in the 10×10×1 mm transplantation, PTEN protein expressions were significantly lower in primordial follicles after transplantation (P<0.05). These results were also mutual for total number of primordial follicles in 2.5×2.5×1 mm, which were higher after transplantation (mean rank 11.92±2.56) compared to the other size groups (10.88±1.48; 9.72±6.36). Conclusions: The most vascularized ovarian tissue samples were found to be 2.5×2.5×1 mm in size and it was found to express more PTEN in the primordial follicles. As a result, compared to the other sample sizes, it also showed the least post-transplantation decline in the number of primordial follicles, indicating less follicular burn-out than the group with larger tissue surface area.