JBRA Assist. Reprod. 2002;06(03):122-122
COMUNICADO
doi: 10.5935/1518-0557.2002.6.3.08
Abstract
Recovery of reproductivity after grafting of cryopreserved germinative tissue in female rabbits submitted to radiotherapy. CG Almodin, AF Moron, VC Minguetti, JOAR Ferreira, H Meister, RC Franco, MRM Radaelli, AA Cavalcante.Materbaby - Human Reproduction and Genetics, Maringá, Pr, Brazil.
Objectives: To recover fertility in female rabbits subjected to ovarian failure induced by radiotherapy with an implant of cryopreserved germinative tissue.
Design: Animal study.
Materials and Methods: Ten adult female rabbits with proven fertility were subjected to right oophorectomy. The left ovary was sutured in the anterior pelvic wall with a small metal marker so as to be easily localized with X-rays. The right ovary after being removed was dissected, maintaining the cortex with a thickness of approximately 2 mm. The tissue was fragmented into small pieces, which were washed in PBS and placed in a freezing medium containing 1.5 M DMSO in Dulbecco's medium with glucose and pyruvate supplemented with 10% fetal calf serum, and homogenized for 30 minutes at 4ºC.
Freezing was initiated at 4ºC by lowering the temperature by 2ºC per minute until -9ºC was reached. At-9ºC the induction of crystallization occurred. The temperature continued to be lowered at the rate of 0.3ºC per minute until - 40ºC was reached, when the tis sue was transferred to liquid nitrogen at - 196ºC. Three weeks after surgery, X-rays were taken to locate exactly the position of the left ovary and the rabbits were submitted to radiotherapy with the application of 200 Centi-Gray (cGy) per day as far as the middle of the anteroposterior pelvic wall thickness of each rabbit. Daily radiotherapies were carried out for five days, totaling 1000 cGy of radiotherapy provoking ovarian failure. Six weeks after radiotherapy, five rabbits were submitted to new surgery and received subcortical implants in the irradiated left ovary with the thawed fragments of the right ovary. Thawing was undertaken in Dulbecco's medium at ambient temperature and the fragments were implanted immediately. The other five irradiated rabbits were maintained as a control group without receiving the implants. Four weeks after implant surgery with germinative tissue, ali the rabbits were kept in a group with males, and clinically evaluated each month.
Results: Three months after the implants four rabbits became pregnant. The rabbits subjected to radiotherapy, and that did not receive the implants, did not become pregnant up until this moment.
Conclusion: The main difficulty of autologous ovarian transplants is vascular anastomosis, which can be replaced with subcortical implants of germinative tissue. The patients submitted to radiotherapy could benefit from the subcortical implant of germinative tissue in one of the ovaries, recovering fertility after radiotherapy.
Keywords: autograft, ovary, cryopreservation, fertility.