Development and Angiographic Use of the Rabbit VX2 Model for Liver Cancer

This pre-clinical liver tumor model can help answer key questions about local regional therapy in the fields of interventional radiology and interventional oncology. The main advantage of this technique, is that it results in a reliable tumor induction by orthotopic allograft implantation. For implementation of the tumor, first confirm a lack of response to pedal reflex.

Once confirmed, the animal subject is placed under anesthesia. An appropriate level of anesthesia is confirmed, and the abdomen is sterilely prepared and draped. After anaesthetisation, use a number 15 blade to make a three to four centimeter vertical, midline skin incision starting from the xiphoid process.

Retract the skin to identify the linea alba, a reflective white band of tissue that travels inferiorly along the midline. And use both blunt and sharp dissection to traverse the linea alba, exposing the peritoneum, taking care not to perforate the underlying bowel tissue. Carefully dissect through the abdominal cavity tissue, to locate the liver, using a haemostat to extend the midline incision one to two centimeters inferiorly through the skin, muscle and peritoneum as necessary.

Identify the left lobe, which is inferolateral to the medial lobe that sits in the midline. And place a dry piece of gauze at the inferior aspect of the incision to prevent the liver from retracting back into the abdomen. Place a new piece of wet gauze over the extracted liver.

Select a one to two cubic millimeter tumor tissue piece, with forceps. And use a number 11 blade to puncture the liver tissue at a 45 degree angle to a 0.5 centimeter deep pocket, taking care not to penetrate the dorsal aspect of the liver capsule. Gently lift the blade in ventrally to create a small pocket in the liver bed, and place the tumor into the pocket.

Place a piece of haemostatic agent over the tumor pocket to promote haemostasis, and to prevent ejection of the tumor piece. And, after confirming haemostasis, return the liver to the abdominal cavity. Then use a three zero polydioxanone suture on a taper needle, in a simple continuous stitch to close the abdominal wall.

And four zero polyglactin 910 sutures on a cutting needle in a continuous, sub-cuticular stitch to close the skin. To confirm a successful tumor placement, palpate the femoral groove in the groin, and make a two to three centimeter linear incision along the groove. Using blunt dissection, locate and isolate the femoral bundle containing the femoral vein, artery and nerve, and use blunt dissection to separate the femoral artery from the rest of the structures in the bundle.

Isolate the artery atop a scalpel handle, and use the Seldinger technique, and a three French introducer kit to introduce a needle into the vessel. Insert a guide wire into the artery. And remove the needle, to carefully advance the three French sheath into the vessel.

Remove the dilator and guide wire from the sheath to complete vascular access. Under fluoroscopic guidance, insert the catheter into the celiac trunk at the T 12 level, and advance the catheter into the left hepatic artery, via the common hepatic, and proper hepatic arteries. When the catheter reaches the left hepatic artery, inject contrast agent to confirm the presence of a hypervascular tumor, which can then be treated with an intra-arterial therapy of choice.

And remove the catheter. Using three zero silk suture, ligate the femoral artery proximally and distally to the insertion point of the sheath, taking care to tighten the knot proximal to the sheath, as it is withdrawn to prevent bleeding. Then use four zero polyglactin 910 sutures, on a cutting needle in a subcuticular stitch to close the groin incision.

Three to four weeks after implantation, the tumor can be visualized macroscopically on the left quadricep of the rabbit. The use of angiography and the injection of a contrast agent as demonstrated, can be used to confirm a successful tumor propagation after placement. Upon necropsy, a successfully implanted tumor should be readily visible.

Since its development, this technique has paved the way for researchers in the fields of interventional radiology and interventional oncology to explore liver tumor local regional therapy in a small animal model.