A mouse heart transplantation model helps investigate cardiac allografts immunologic and the parasagittal rejection mechanisms. This understanding would help develop a unique approach to improving patient's long-term survival. This cervical transplantation surgery is performed without stitching using a cuff method.
Hence, it decreases the complexity in vessel anastomosis and avoids the interference with blood supply and venous reflux of the lower body. Demonstrating the procedure will be Dr.Xin Mao, a surgeon from our laboratory. To begin, place the recipient mouse on a heating pad at the operating table and shave the hair over the surgical area.
After disinfecting the surgical area, make a 1.5 to 2 centimeter incision parallel to the cervical midline from the right mandibular angle to the tail end. Dissect approximately one centimeter of the right external jugular vein using an electro-coagulator and micro-forceps. Clip the vein at the proximal end with an atruamatic microvascular clamp and ligate it at the distal end.
Pass the distal end of the vein through a 22 gauge polyurethane barbed cuff with a bevel end and superficial grooves. Fix the vein with the handle of the cuff using a microvascular clamp. Remove the 8-0 ligation suture at the distal end, turn the lumen over the cuff hooked by the superficial barb inside out, and fix it with a 10-0 surgical suture in the grooves of the surface.
Resect the right sublingual gland to form a fossa for implanting the cardiac graft and reserve the right lobe of the submaxillary gland and the right sternocleidomastoid. Dissect the right common carotid artery for approximately one centimeter using micro-forceps and clip the artery with an atraumatic microvascular clamp at the proximal end. Ligate and cut off the artery.
Pass the distal end of the artery through a 26 gauge polyurethane barbed cuff with a bevel end and grooves on the surface. Fix the artery with the cuff's handle using a microvascular clamp. Remove the ligation suture at the distal end, turn the lumen inside out over the cuff, and fix with a superficial barb and grooves with a 10-0 surgical suture.
After preparing the recipient's vessels, drop 100 international units per milliliter heparin saline on the vessels to prevent thrombosis. Cover the cervical incision with wet saline gauze for subsequent implantation. Shave the abdominal hair using an electric razor.
After disinfecting the surgical area, incise the abdomen along the midline from the symphysis pubis to the subxiphoid and expand the incised area with a retractor. Dissect one centimeter of the abdominal aorta and inferior vena cava using an electro-coagulator and a micro-forceps and perform heparinization by injecting one milliliter of physiological saline supplemented with 250 international units per milliliter of heparin through the inferior vena cava. Excise the abdominal aorta and inferior vena cava.
Excise the thorax along the anterior axillary line on both sides using a surgical scissor to separate the chest wall, then ligate the superior vena cava with an 8-0 surgical suture. Insert a scalp needle at the suprahepatic inferior vena cava. Then inject ice cold physiological saline supplemented with 100 units per milliliter heparin through the scalp needle from suprahepatic inferior vena cava to profuse the donor heart until the blood color fades.
Reperfuse the donor heart with two to three milliliters of ice cold histidine-tryptophan-ketoglutarate solution from the aortic arch to protect the donor myocardium. Ligate the superior and inferior venae cavae and the pulmonary vein with a 5-0 surgical suture. Dissect and cut off the donor aorta and pulmonary artery before branching.
Then divide the superior and inferior venae cavae and the pulmonary vein to remove the donor's heart. Implant the donor heart into the cervical pocket of the recipient mouse in an inverted position. Pull the cuff with an everted recipient jugular vein into the lumen of the donor pulmonary artery to perform end-to-end anastomosis.
Ligate the cuff using the grooves on the surface through a 10-0 surgical suture to fix the anastomosis. Employ a similar procedure for end-to-end anastomosis of the donor aorta to the recipient carotid artery. Release the atraumatic microvascular clamp of the jugular vein followed by the carotid artery to reperfuse the donor's heart.
Fix the cardiac graft and suture it properly to prevent twisting of the graft. Close the cervical incision with continuous sutures using a 5-0 polyamide monofilament suture. Using this mouse cervical heterotopic heart transplantation model, the survival rate of recipient mice was approximately 95.2%All cardiac allografts were lost within eight days after transplantation.
In contrast, all the isogenic heart transplants survived beyond four weeks. grooves and cuff for better fixation of everted vessels, avoiding repeated operation of vessels. The modified cuff method for vessel anastomosis in this surgery is also applicable for another anastomosis in different organ transplantation animal models.
