Optimizing Mouse Urodynamic Techniques for Improved Accuracy

The goal of this study is to improve the urodynamic technology to increase accuracy of the urine measurement. Accurate measurement of urinary parameter awake meiosis is crucial understanding lower urinary tract dysfunction, particularly in condition like a neurogenic bladder, post-traumatic spinal injury. We developed a unique method utilizing cyanoacrylate adhesive to create a waterproof skin barrier around the urethral meatus and abdomen, preventing urine absorption and ensuring precise measurements of voided volume.

We would use this more accurate assay to evaluate urinary function in the spinal cord injury animal models, and in other neurodegenerative disease. To begin, cut a 30 centimeter polyethylene PE 30 tube. Carefully insert about three fourths of the 25 gauge needle into one end of the tube.

After preparing a one milliliter syringe, fill it with sterile 0.9%sodium chloride solution, and connect it to the 25 gauge needle. Then gently infuse saline to check for a proper round tip and no leakage from the ends of the needle. Prepare two steel wires each 20 centimeters in length.

Then insert a 25 gauge needle on one side of the wire. Use solder to attach the pin to the other end of the striped wire. To begin, fix the limbs of the anesthetized animal with tape.

Use an electric razor to shave the fur of the lower abdomen and around the urethral meatus. Under the surgical microscope, use Metzenbaum straight blunt scissors to create a one to two centimeter incision in the midline of the abdominal pelvic skin. Incise the fascia and muscles in the midline to expose the bladder through the incisional wound.

Once the bladder is visible through the wound, retract any surrounding organs or tissues as needed to obtain a clear view of the surgical field. Then grasp the bladder dome and use a 5/0 non-absorbable monofilament suture with a taper tip needle to place a purse string. Using micro scissors, create a small cystostomy within the purse string and make a hole until urine flows out.

Now, grasp the round tip end of the catheter and insert it through the hole. Once the tip of the tube has passed through the hole, suture the purse string around the tube. After that, gently pull the tube outward until the tip is felt under the suture.

Then slowly infuse one milliliter of saline from the other end of the tube to distend the bladder, and check for any leakage around the catheter. Once the saline comes out of the urethra, withdraw the saline to decompress the bladder. Use surgical scissors to extend the abdominal incision up to the pelvic floor.

In line with the bladder, move the muscles and membranes to the pudendal canals and locate the urethra and external sphincter muscle. Using the needle containing the electrode, puncture the skin bilaterally one centimeter away from the urethral meatus. Then carefully grab the hook tip with forceps and gently pull the needle away from the skin Using the electrodes tip, carefully hook the external urethral sphincter muscle bilaterally.

Use the 3/0 non-absorbable monofilament to suture the pelvic and abdomen muscles and skin. To fix the electrodes in place, apply a thin layer of cyanoacrylate glue to the skin where the electrodes exit. Next, use a 0.5 to 10 microliter micro pipette to withdraw the accelerator liquid to dry the glue.

Then add the accelerator liquid to ensure a proper adhesive reaction. Prepare an inverted polystyrene weighing boat, 4.5 centimeters in length, width, and depth. Cut it into a triangle shape with a base of four centimeters to place the mouse's urethral meatus in this space.

Put the disposable base mold under the space for collecting the urine. Then reposition the mouse in a prone position and carefully move it onto a custom made plate, equipped with a gas mask. Ensure that the urethral meatus is properly positioned within the groove.

Gently restrain the head and limbs of the mouse with tape and place the plate on a heating pad until the mouse regains full consciousness. To begin, implant a bladder catheter and EUS electrode in the anesthetized mouse. After waterproofing the mouse's skin, prepare it for the urodynamic procedure.

Ensure that the mouse is fully recovered from anesthesia, monitoring respiratory function throughout. Then take a 20 milliliter syringe and fill it with sterile 0.9%sodium chloride solution at room temperature. Secure the syringe to the infusion pump and set the infusion speed to 0.01 milliliters per minute.

Now connect the syringe by the PE 30 tube to one side of the three-way connector. Connect the bladder catheter to the other side and to a pressure transducer. Fix the pressure transducer at the same level as the mouse bladder.

Then attach one ground line hook to the skin and the other to the electrode connector sites. Record the pressure in the software. After starting the software, check the intravesical pressure and external urethral sphincter electromyography signals.

Save the sample name and set the time. Finally, start the pump infusion and record the signals.