Mouse Pneumonectomy Model of Compensatory Lung Growth

The goal of this procedure is to perform a left pneumonectomy to induce compensatory growth of the right lung. This is accomplished by first performing a left thoracotomy and exposing the left hilum. The second step of the procedure is to ligate the left helium and left pulmonary artery.

The third step is to remove the left lung. The final step is to close the thoracotomy. The mouse pneumonectomy model of compensatory lung growth can be utilized in conjunction with other biometric or biochemical techniques to elucidate mechanisms of alveolar growth and regeneration.

This method can answer some key questions in the lung development and regeneration field, such as what are the key cellular processes involved in septation and what are the critical cellular molecular processes necessary to reinitiate septation? Generally, investigators who are new to this technique will struggle with one of several key steps. They may have difficulty with tracheal cannulation.

They may have difficulty creating an adequate surgical window. They may have difficulty identifying the hilum and clipping it, and they also may have difficulty with avoiding injury to the left lung during sham thoracotomy. Demonstrating this procedure will be Shang Lu, a senior laboratory assistant for my laboratory To begin after inducing anesthesia in the mouse with 2%isof fluorine, shave the left thorax and neck area with an electrical shaver, apply artificial tear ointment to the eyes of the mouse and decontaminate the area by swabbing with chlorhexidine three times followed by isopropyl alcohol three times followed by Chlorhexidine.

Three times. Confirm the depth of anesthesia by documenting the lack of a response to a poor pinch after making a one centimeter vertical incision over the anterior mid neck to expose the larynx, use serrated 10 centimeter forceps to lightly retract the strap muscles. Then use the tips of a straight scissors to spread the strap muscles.

Next orally, insert a 22 gauge blunt tip angio catheter into the mid trachea and visually confirm placement through the incision. Place the mouse on a rodent ventilator and maintain anesthesia with 2%isof fluorine, and a pressure limit of 15 centimeters.Water. Position the still anesthetized mouse in the right lateral decubitus position with the back left side facing the operator.

Place self-sealing plastic wrap over the body of the mouse as a sterile drape. Use blunt tipped curved scissors to make a two centimeter long cut parallel to the ribs at the fourth and fifth intercostal space. Then insert the tips of the scissors and dissect the skin away from the underlying ribs and intercostal muscles.

Place four retractors on the skin to form a 1.5 by 1.5 centimeter surgical window. Secure each retractor to the cork board. Use curved forceps to dissect down to the ribs and then bluntly dissect the intercostal.

To expose the fourth and fifth ribs, use one tip of a curved forceps to make a hole to enter the thorax cavity. Now use the lower blade of a pair of blunt tip micro scissors to depress along the incision until the lower blade enters the thoracic cavity. Make a 0.5 centimeter incision between the ribs and then repeat in the opposite direction.

Then open the thorax along the anterior posterior axis by inserting two retractors and securing them to the corkboard. Now load the micro clip applicator. Next, using curved blunt tipped forceps held in the non-dominant hand, grasp the left lung and displace the upper portion laterally and inferiorly through the thoracotomy until the left pulmonary artery and bronchus are exposed.

Then hold the loaded titanium vascular micro clip replicator in the dominant hand with the body of the applicator in the palm and the curve tip pointing away from the palm. Slide the applicator tip into the thorax along the curvature of the posterior aspect of the left lung, and clip the left bronchus and pulmonary artery. Remove the applicator but keep the left lung retracted.

Grasp the blunt tip micro scissors with the right hand and cut the bronchus and pulmonary artery distal to the clip and remove the left lung. After removing the lung, take out the rib retractors. Then use the curved blunt forceps to pinch up one centimeter of skin inferior to the incision but above the level of the diaphragm, and insert a 24 gauge angio catheter through the skin and into the left thoracic cavity.

Next place, two interrupted five zero proline sutures around the fourth and fifth ribs. To close the thoracic cavity, remove the skin retractors and use two sets of forceps to approximate the skin along the length of the incision and use tissue adhesive to glue the skin closed. Finally, connect a three milliliter lu lock syringe to the angio catheter and remove residual air by applying gentle suction and withdrawing the angio catheter.

Finished by gluing the neck, incision closed using two sets of forceps as for the closure of the thoracic incision. After exposing the left lung of the anesthetized mouse as previously shown, use curved blunt forceps to lift the rib cage and allow air into the left chest cavity Laser 24 gauge angio catheter into the left, the thoracic cavity as previously shown, being careful not to injure the left lung. Using five zero proline suture and being careful not to puncture the lung.

Place two lengths of suture material into the third and fourth and fifth and sixth rib into spaces. Place both lengths of suture material before tying to lessen the risks of left lung herniation. Tie the suture material to make two interrupted stitches.

Glue the skin over the thoracic incision. Remove residual air with the angio catheter and glue the neck incision as previously shown. Turn off the isof fluorine and administer 0.1 milligrams per kilogram of buprenorphine and 0.5 milliliters of normal saline subcutaneously.

When spontaneous respiration resumes, remove the endotracheal tube. Observe the mouse until it is ambulatory. Walking typically resumes several minutes after removal of the endotracheal tube.

Administer 0.1 milligrams per kilogram of buprenorphine by intraperitoneal injection twice daily for three days after surgery. Carefully monitor the animal during these three days and take care not to open the surgical site when handling animals. This image shows weight loss after surgery.

24 hours after surgery, pneumo somy mice will lose an average of 1.5 grams and sham mice will lose an average of 1.1 grams. Both groups regain their preoperative weight by postoperative day three. This fluorescent image shows tropo elastin immunofluorescence staining of the accessory lobe under control conditions.

Here, tropo elastin immunofluorescence of the accessory lobe is shown 72 hours post pneumo omy existing air spaces are increased. This final TRO Elastin immunofluorescence image shows the accessory lobe four weeks post Pneumo Otomy. Note the Loba growth and Reation.

After watching this video, you should have a good understanding of how to perform the mouse pneumonectomy model of compensatory lung growth and how to perform the sham thoracotomy, which is used as a control for this procedure.