Surgical Techniques for Catheter Placement and 5/6 Nephrectomy in Murine Models of Peritoneal Dialysis

This method can help answer key questions in the Peritoneal Dialysis field about Peritoneal or Systemic alterations in response to fluid exposure either under uremic or not uremic conditions. The main advantages of this technique are that large amounts of fluid can be injected intraperitoneally over a long treatment period and that it allows the use of genetically modified animals. The implication of this technique extend toward the therapy and diagnostics of structural and functional peritoneal deterioration, as it facilitates potential, therapeutic strategic testing and biomarker evaluation.

We first had the idea for this method when we anticipated the need for using genetically modified mice to starting the molecular cues involved in peritoneal damage. For catheter placement, after shaving the right flanks and backs of each animal, confirm a lack of response to toe pinch and apply ointment to the animal's eyes. Next, place the first animal on its left flank on the surgical table and disinfect the exposed skin with 1%chlorhexidine gluconate solution.

Use blunt scissors to make a 0.5 centimeter cut skin incision on the right flank of the body. Then, carefully separate the skin from the adjacent muscle layer until the skin covering the entire back of the animal is well separated. Make a one millimeter diameter incision in the muscle layer through the skin incision and insert the tip of the catheter and the first plastic ring into the muscle incision.

Suture the peritoneal wall tightly around the catheter with the 5-0 or 6-0 non-absorbable suture, with one plastic ring inside the peritoneal cavity and the other between the muscle and the skin. The sutures should be prepared before the incision is made and the muscle should not be released until the catheter is inserted. Otherwise, since the incision is very small, it could be difficult to find it again.

Insert the access port into the subcutaneous space towards the tail of the mouse and close the wound with a second suture. Then, return the animal to its cage after full sternal recumbency. Four to seven days later, to initiate the peritoneal dialysis treatment, first load a syring with two milliliters of peritoneal dialysis fluid, and disinfect the skin surrounding the port with 1%chlorhexidine gluconate solution.

Then use one hand to restrain the animal by the tail and access port, and inject the fluid into the port with the other hand using a beveled needle. For a 5/6 Nephrectomy and catheter placement, after preparing the animals for surgery, as demonstrated, make a 0.5 centimeter skin incision on the left side of the animal close to the bottom of the ribs. Open a small incision in the muscle to extract the left kidney from the peritoneum, and remove the capsule and the adrenal gland.

Use a cauterizer to burn and cut the extremities of the kidney and return the kidney to the peritoneal cavity. Then, close the muscle and the skin wounds with insoluble 5-0 or 6-0 sutures and return the animal to its cage when it has fully recovered. The next day, make a 0.5 centimeter skin incision on the right side of the animal and separate the skin at the back of the animal from the muscle, as demonstrated.

Make a 0.3 to 0.4 centimeter incision in the muscle and extract the right kidney from the peritoneal cavity. Remove the capsule and the adrenal gland and use a non-absorbable 5-0 or 6-0 suture to ligate the kidney vein, artery, and ureter. Now remove the kidney completely and insert the catheter so that the muscle is maintained between the two plastic rings, as demonstrated, before closing the muscle wound.

Introduce the access port into the sub-cutaneous space and close the skin, as demonstrated. Then return the animal to its cage with monitoring until full recovery, and allow the animal to recover for at least 10 days before administering the hyperosmotic fluid, as demonstrated. Mouse perial peritoneal tissues obtained from the most distant area of the catheter, demonstrate an increased thickness and cell recruitment during dialysis that is further aggravated in the nephrectomized animals.

Thymus epithelial cells also exhibit an altered morphology due to inter-cellular union degradation induced by the peritoneal dialysis. Serum samples from nephrectomized mice, indicate that a 5/6 Nephrectomy induces a uremic state, increasing the Ureic Nitrogen levels during the course of the experiment, compared to baseline. More over, when the kidneys are fully functional, the Ureic Nitrogen levels remain similar to the basal state, even in mice exposed to peritoneal dialysis fluid.

These techniques can be completed in five to seven minutes. Without the nephrectomy, 15 to 20 minutes. For the left kidney cauterization, 20 to 25 minutes.

For the right kidney removal and catheter placement, if its methodology is performed properly. After its development, this technique paved the way for researchers in the field of peritoneal dialysis to explore therapeutic options for peritoneal preservation in renal patients subjected to peritoneal dialysis treatment.