Our protocol provides an easy, cost-effective, reproducible and clinical relevant model for researchers in the field of venous intimal hyperplasia. Our protocol is economically, clinically, and technically balanced. Therefore, it is highly recommended for researchers who want to apply their in vitro outcomes to an in vivo setting.
We believe that our protocol can be applied to a larger animal model for the development of new treatment strategies in ischemic heart and lower extremity diseases. Our protocol is mainly relevant to the field of cardiovascular surgery. However, it may also be used to address degenerative changes in arteriovenous fistulas in patients with end stage renal disease.
After local anesthetic, and prophylactic antibiotic analgesic administration, disinfect the surgical site with 10%povidone-iodine. And make a 50 to 60 millimeter incision with a surgical scalpel in the cervical region of the anesthetized male Japanese white rabbit. Bluntly dissect the subcutaneous tissues and fascia to expose a 20 to 30 millimeter segment of the jugular vein.
And use 4-0 silk sutures to ligate all of the branches of the exposed vein. Place a 2-0 silk suture around the internal and external jugular veins and make a one millimeter incision in the venous wall of the distal side of the vein. Insert a 2-French balloon catheter from the cut toward the proximal side of the vein.
And ligate the 2-0 silk suture at the distal sites of the jugular veins. Inflate the balloon with 200 microliters of air. And use the balloon to denude the intima of the vein three times for endothelial exfoliation.
After the third passage, ligate the proximal end of the vein and cut the vein at the distal site. Then insert a 20 gauge intravenous catheter into the harvested vein from the distal to the proximal direction, and cut the vein at the proximal site. To interpose the carotid artery with the harvest jugular vein, expose a 20 to 30 millimeter segment of the ipsilateral carotid artery.
And separate the artery carefully from the nearby vein and nerve. Ligate all the branches of the exposed vein with 4-0 silk suture. And intravenously administer 200 International Units per kilogram of heparin sodium.
Clamp the proximal and distal ends of the artery with surgical rubber clamps. And cut the artery between the clamps. Inject normal saline into the incised carotid artery proximally and distally to distend the artery.
And place the harvest vein near the artery to anastomose the vessel in a reversed end-to-end fashion. To anastomose the proximal end of the vein to the distal end of the artery, place two anchor stitches of 8-0 polypropylene at the site and the opposite site. Add stitches the upper side of the anastomosis line between the anchor stitches.
Flip the artery and the vein graft upside down. And add stitches on the remaining part of the anastomosis line. Next, remove the intravenous catheter from the vein and clamp the vein graft proximally.
Declamp the carotid artery distally. And observe whether the vein graft expands gradually. Using 8-0 polypropylene interrupted sutures, anastomose the distal end of the vein to the proximal end of the artery.
And declamp the artery to check for bleeding from the anastomosis sites. Finally, ligate the internal carotid artery with a 4-0 silk suture to simulate a poor runoff condition and to facilitate intimal hyperplasia. Then clean the wound with saline.
Close the incision with 3-0 polyglactin 910 in layers. And allow the rabbit to fully recover with monitoring before returning the animal to its home cage. In this representative image, a successful intimal hyperplasia at 2 weeks after venous interposition surgery can be observed.
Here, the therapeutic effects of microRNA-145 loaded poly(lactic-co-glycolic acid)nanoparticles on the intimal hyperplasia morphology can be observed. Indeed, treatment with microRNAs loaded with poly(lactic-co-glycolic acid)nanoparticles results in a significant attenuation of intimal hyperplasia. In addition, immunostaining for Ki-67, a cell proliferative marker, reveals fewer Ki-67-positive cells within the microRNA-145 treated group indicating a phenotype change in the vascular smooth muscle cells from the immature proliferative state to the mature contractile state.
The main goal of our protocol is to achieve patency of the implanted graft. It is also important to confirm that the graft expands after declamping the carotid artery.
