RESUMO
UNLABELLED: Freezing ovarian tissue is acquiring a greater significance due to the increase in oocyte long term survival rates, which provides young women with malignancies an alternative to preserve their fertility. OBJECTIVES: 1. Assessing the physiological viability of ovarian tissue auto-transplants. 2. Determining possible differences between the two cryoprotectors that were used: dimethyl sulfoxide (DMSO) and propanediol (PROH). DESIGN: Experimental and prospective study assessing ovarian tissue viability after freezing and auto-transplantation in eight female sheep. MATERIALS AND METHODS: A bilateral oophorectomy was performed on the sheep under general anesthesia. The ovarian cortex was dissected and frozen using either DMSO (1.5 M) or PROH (1.5) with saccharose. The thawed tissue was auto-transplanted within the following one to six months, and weekly progesterone measurements were carried out in order to assess ovarian tissue functionality. Once ovulation levels were obtained, the female sheep were continuously exposed to the male in order to obtain the gestation process. RESULTS: Ovulation activity was recovered in seven of the eight female sheep (87.5%) submitted to auto-transplants within an average period of time of 62.8 +/- 9.1 days, as evidenced by serum progesterone levels. These findings were obtained regardless of the cryoprotector used. Two gestations were obtained, and these are evolving normally, as assessed by ultrasonic methods. CONCLUSIONS: The present study shows that ovarian function is adequately restored in oophorectomized sheep using ovarian tissue auto-transplantation, and produced the first pregnancies obtained through this technique in Latin America. It is possible to assume that these results can be reproduced in women.