Resumen

La congelación de tejido ovárico está adquiriendo gran importancia por un incremen­to en las tasas de supervivencia a largo plazo de mujeres jóvenes con enfermedad ma­ligna, que necesitan tener alternativas para preservar su fertilidad.
Objetivos. 1. Eva­luar la viabilidad fisiológica del tejido ovárico autotrasplantado. 2. Determinar si existe diferencia entre dos crioprotectores utilizados, dimetilsulfóxido (DMSO) y propanodiol (PROH).
Diseño. Estudio experimental y prospectivo para evaluar la viabilidad del te­jido ovárico después de congelación y autotrasplante en ocho ovejas.
Material y mé­todo. Se realizó ooforectomía bilateral en ovejas bajo anestesia general. La corteza ovárica se disecó y se congeló ya sea en DMSO (1 .SM) o PROH (1.SM) con sacarosa. Se realizó autotrasplante del tejido descongelado entre uno y seis meses posteriores y determinaciones semanales de progesterona para evidenciar la funcionalidad del teji­do ovárico. Una vez que se obtienen niveles ovulatorios, las ovejas fueron expuestas al macho de forma continua en búsqueda de gestaciones.
Resultados. Se consiguió retor­no de actividad ovulatoria en siete de ocho ovejas autotrasplantadas (87.5%) en un tiempo promedio de 62.8 ± 9.1 días evidenciado por niveles séricos de progesterona. Estos hallazgos fueron independientes del crioprotector utilizado. Se lograron dos ges­taciones, las cuales hasta el momento son evolutivas evaluadas por ultrasonido.
Con­clusiones. El presente estudio nos demuestra una adecuada restauración de la función ovárica en ovejas ooforectomizadas con autotrasplante de tejido ovárico y las primeras gestaciones logradas por esta técnica en Latinoamérica. Es posible suponer que estos resultados son reproducibles en mujeres.

Palabras clave: Gestación, autotrasplante, tejido ovárico criopreservado, viabilidad ovocitaria 

Abstract

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.

Key words: Gestation, auto-transplant, cryopreserved ovarian tissue.