The scope of this specific area of our research is the provision of highly standardized and controlled animal models for specific conditions and diseases. Using this protocol for subtotal nephrectomy, we provide a standardized model for renal insufficiency in rats. Our protocol offers the advantage of intraabdominal axis to other visceral organs.
This is especially valuable if simultaneous procedures on other organs are required for the desired animal model. The most relevant current experimental challenge is the fact that surgically reducing overall renal parenchyma by standardized amount does not necessarily result in the same degree of renal insufficiency. So further postoperative certification through lab testing might be required.
To begin, arrange the polyfilament ligatures, silicone vessel loops, blunt overhaul clamps, fine preparation scissors, forceps, hemostatic patches, exposure apparatus, a heating pad, and surgical preparation hooks on the operating table. To the anesthetized rat, administer 100%oxygen through a neonatal face mask. Shave the desired access area and disinfect the surgical site by applying sterilized cotton swabs in a circular motion with alternating scrubs of 70%ethanol and povidone-iodine.
To perform a median mini-laparotomy, make an initial approximately three-centimeter median cutaneous incision over the abdomen, followed by an incision on the fascia along the linea alba. Achieve surgical exposure of the kidney by positioning surgical compresses and preparation hooks. Then, only touch the renal parenchyma with humidified cotton swabs.
Expose the kidney by grabbing the perirenal fat attached to the Gerota's fascia. Apply tension to lift the fascia off the renal parenchyma locally. Incise and undermine the fascia with the sharp end of one scissors edge and continue with a longitudinal dissection of the Gerota's fascia.
Next, perform a blunt degloving of the Gerota's fascia using closed scissors. Gradually undermine the fascia around the parenchyma and fold the fascial capsule medially. Sling the renal hilum with a silicone vessel loop for better vascular control.
Place the tip of the forceps into the retroperitoneal space to stabilize the kidney to avoid a dorsal escape of the kidney during the cutting process. Then, using scissors, perform the cranial sharp one-third renal colectomy in one precise-aimed stroke. Achieve hemostasis by applying a hemostatic patch or using manual compression with blunt instruments.
Alternatively, apply a hilar YASARGIL clamp to reduce blood flow. Perform the caudal sharp one-third renal colectomy in the same manner as the cranial colectomy. Use an angulated dissection plane to retain more renal parenchyma at the hilar side and less on the lateral side to avoid hilar injury and reduce urinary leakage from the pelvicalyceal system.
After mobilizing the kidney, tunnel the renal hilum using blunt overhaul clamps, sling the renal hilum with a polyfilament ligature. Place a secure sliding knot on the renal hilum close to the abdominal vessels to occlude renal blood flow and the ureter. Sharply dissect the hilum using scissors and remove the kidney.
Then, control the hemostasis and cut off the ligature ends. Place a corner suture on the abdominal fascia using a polyfilament suture. Continue suturing the abdominal fascia with a running suture, grabbing approximately two millimeters of tissue per bite and spacing each bite four millimeters apart.
Suture the cutaneous layer with single stitches, grabbing three millimeters of tissue per bite and leaving six millimeters between each stitch. The physiological values of the remnant kidney parenchyma showed oxygenation levels of approximately 60%indicating viability after resection. Malperfused renal tissue displayed significantly lower oxygenation levels at 20.9%consistent with non-viable tissue.
Perfusion values indicated physiological perfusion in the remnant kidney, reinforcing tissue viability.
