Orthotopic Left Lung Transplantation in Rats

My research focused on developing standardized, reproducible left lung transplantation model to investigate post-transplant complications, particularly chronic rejection, and to better understand the mechanism driving long-term graft failure. Our protocol offers a shorter learning curve, single operational capability, and a higher reproducibility compared to existing techniques. Our standardized direct lung transplantation model provides a reliable platform for studying complications after lung transplantation and can accelerate translational research to improve graft survival.

In the future, our laboratory will focus on the study of chronic rejection after lung transplantation in order to improve the long-term survival rate of lung transplant recipients. To begin, obtain 14-gauge and 16-gauge intravenous catheters and blades. Trim the catheters into a cuff with a tail with a blade.

Then divide each cuff into a body and a tail, each approximately two to three millimeters in length. Using a scalpel, create superficial scratches on the cuff body to increase friction for suture fixation. To harvest the donor lung, retract the tongue of an anesthetized rat outward and upward using forceps.

Position a surgical lamp anterior to the neck to illuminate the glottal opening clearly. Now, insert a 14-gauge intravenous cannula into the airway through the glottis. Set the ventilator to pressure controlled mode.

Then, input the weight parameters, adjust the pressure to 15 centimeters of water, and connect the ventilator. Observe the rise and fall of the chest to ensure synchronization with the ventilator frequency. Next, fix the limbs and head using tape or restraints.

Make a midline incision along the abdominal wall. Inject heparin through the exposed peritoneal vein, then allow systemic circulation for three minutes to ensure complete heparinization. Cut the diaphragm and open the chest cavity from the midline of the sternum.

Then, fix the chest wall on both sides with hemostats. Remove the thymus to expose the chest cavity organs. Sequentially, cut the superior vena cava, inferior vena cava, and the left and right auriculi.

Now, inject cold saline into the root of the pulmonary artery using a 20-milliliter syringe over one minute for low pressure perfusion until the donor lung turns completely white. Cut tissues connecting the donor lung and extract the donor heart and lung in block. Soak the donor heart-lung block in pre-cooled saline.

Position the heart-lung block on ice under a microscope. Grip the trachea with a hemostat and secure it in plasticine. Cover the lungs with wet sterile lens paper.

Now, use forceps to separate the pulmonary artery, bronchus, and pulmonary vein under the microscope. Ligate the bronchus close to the lung using 6-0 surgical sutures. Use spring scissors to cut the pulmonary artery, bronchus, and pulmonary vein.

Extract the pulmonary artery, bronchus, and pulmonary vein from respective cuffs made from 16-gauge, 14-gauge, and 16-gauge indentation catheters. Fix the tube walls to the cuff with 8-0 surgical sutures. Preserve the donor lungs in saline, and place them back on ice until implantation.

Depilate the left thoracodorsal region of the recipient animal. Position the animal in the right lateral decubitus posture on a thermostatic operating table. Now, make an incision through the skin and chest wall at the point of the apical impulse in the fourth intercostal space to access the thoracic cavity.

Use an eyelid retractor to open the thoracic cavity. Then, gently push the left lung aside using a moist cotton swab to expose and sharply transect the inferior pulmonary ligament. Next, grasp the left lung with forceps and retract it outside the thoracic cavity.

Secure the hilum with a hemostat, then stabilize it with modeling clay. Now, dissect the pulmonary hilum to separate the pulmonary artery, pulmonary vein, and bronchus. Clamp the proximal ends of the pulmonary artery, pulmonary vein, and bronchus using vascular clamps.

Pre-tie the recipient's pulmonary artery, bronchus, and pulmonary vein with 8-0 surgical sutures for rapid anastomosis. Trim a platform on the recipient's clamped left lung to facilitate the placement of the donor lung. Make small incisions at the distal ends of the pulmonary artery, pulmonary vein, and bronchus.

Rinse the pulmonary artery and pulmonary vein with heparinized saline to prevent clot formation. Then, take the donor lung from ice and position it on the prepared platform of the recipient's left lung. Use forceps to lift one side of the cut opening, then sequentially implant and ligate the cuffs of the pulmonary artery, pulmonary vein, and bronchus into the recipient.

Open the micro hemostatic clip and observe the donor lung turning from white to red. Inspect the anastomotic sites for any signs of bleeding. Now, remove the recipient's left lung and return the donor lung into the thoracic cavity.

Wipe the chest cavity dry with sterile cotton. Then, close the thoracic cavity layer by layer. Wait for spontaneous breathing recovery before removing the ventilator.

After one hour, the recipients were free to eat. Six months after transplantation, CT imaging showed that the ventilation of the transplanted lungs was comparable to the sham group, indicating preserved lung function. The macroscopic appearance of the lungs did not differ visibly between the sham and transplanted groups, showing no signs of deterioration or abnormality.

Hematoxylin and eosin staining of the lung tissues revealed no significant pathological changes in the transplanted lungs compared to the sham group, with preserved alveolar structures and absence of inflammatory infiltration.