Surgical Approach, Challenges, and Resolutions for Uterus Transplantation in Rats

Right uterus transplantation belongs to one of the most complex microsurgical procedures mastered by only a few. Our protocol shifts right uterus transplantation from a experimental stage to an applicable methodology. Our protocol leads to a high rate of live births post uterus transplantation.

It soon will promote the application of right uterus transplantation for actual research. Patience and stamina are key traits during the whole procedure. After performing a median laparotomy, on an anesthetized rat, harvest the right uterine horn with the common uterine cavity and cervix along with vascular pedicles.

Cauterize the wound and ligate the left uterus horn with a 4-0 polygalactin suture. Now sever the left uterine horn adjacent to the branching from the common uterine cavity. Separate the cervical and vaginal portion of the future graft from the rectal attachment.

Separate the future graft from the paravaginal and paracervical ligaments. Using diathermy, dissect the vagina around two to three millimeters caudal of the cervix. Locate the uterine artery and veins at their origins.

Ligate all vessels caudal of the uterine vessels with 8-0 polyamide place. Place 8-0 polyamide ligatures directly around the right common iliac artery and vein proximal to the aortic and caval bifurcations. Make a 0.5 to one millimeter long incision into the right common iliac artery directly adjacent to the bifurcation.

Insert a blunt straight 25 gauge needle into the lumen to flush it out. Secure the needle with a 6-0 polyamide ligature. To enable outflow during flushing, dissect the common iliac vein caudal to the ligature at the right common iliac vein.

Using a three milliliter syringe, flush the uterus with cold Ringer's solution, followed by organ preservation solution both supplemented with heparin and xylazine. Cut the common iliac artery caudal of the ligature at the abdominal aortic bifurcation. Then using blunt dissection, sever the common iliac vessels from the aorta vena cava bifurcation at the division of the uterine vessels.

And remove the transplant when the uterine tissue turns pale. Place the transplant into the cold organ preservation solution to facilitate back table preparation and storage before transplantation. After placing the graft in the abdominal cavity and positioning the graft vein, place one 10-0 polyamide stay suture into the cranial corner and one loose suture into the caudal corner of the slit on the right common iliac vein.

Anastomose one side of the graft vein into the recipient's vein using six to eight loops of a continuous suture. Similarly, anastomose the other side of the vessel starting from the outside. Then using 10-0 polyamide, tie one knot at the cranial stay suture and another knot at the caudal stay suture.

Perform arterial anastomosis using 10-0 polyamide interrupted sutures at the right common iliac arteria with eight to 10 loops. To begin graft perfusion, when the sites appear patent, release the vascular clamps on the graft vessels and check the graft for signs of reperfusion. Connect the vaginal cuff of the transplant to the vaginal vault using six to seven 6-0 polygalactin interrupted sutures.

Using five to seven polyamide 7-0 interrupted sutures, anastomose the graph uterine horn end to end to the remaining recipient cranial uterine segment. Monitor the rat post operation. Post uterine transplantation, two Group 1 rats displayed signs of pregnancy.

However, examination revealed dilated uterus, suggesting that the pups developed normally, but the rats failed to deliver the pups. Histological examination in the fetuses showed that the pups developed up to parturition. Five Group 2 rats displayed pregnancy with three giving birth to pups.

The Lewis female gave birth twice. All pups in the first litter survived while only two of the three pups from the second litter survived. The brown Norway female also gave birth twice and all surviving pups displayed normal development.

The protocol adaptation improved both direct surgical outcomes and the rate of live births following uterine transplantation. It increased the two-week graft survival rate from 50%in Group 1 to 75%in Group 2. It is important to keep the suture knot at the caudal corner loose for better adjustment and to prevent pursed string effects.

Right uterus transplantation is particularly suited to assess pre-transplant approaches that may improve uterus transplantation outcomes such as ex vivo hypodermic organ perfusion or other techniques for the mitigation of organ injury. In general, uterus transplantation in animals has been and is a must to introduce to establish uterus transplantation in the clinic.