preparation of catheter and electrodes for cystometry and external urethral sphincter electromyography recordings

Misurazione urodinamica precisa in topi svegli utilizzando barriere cutanee cianoacriliche

The storage and release of urine are dependent on the coordinated activity of the urinary bladder and external urethral sphincter (EUS). In some pathologies such as neurogenic bladder, both the bladder detrusor muscles and the sphincter can become dysfunctional, leading to significant bladder problems, especially after traumatic spinal cord injury(SCI)1.
Small rodents are commonly used as an experimental model to study the preclinical function of the lower urinary tract (LUT)2. Filling Cystometry (FC) and EUS electromyography (EUS-EMG) recording techniques can provide precise objective information depending on the choice of methods, accurate measurement, and interpretation of results3. Urodynamic tests are commonly used to evaluate the voiding volume (VV), voiding efficiency (VE), and bladder capacity4. VE measures how effectively the bladder can empty itself. It is calculated by dividing the voided volume by the sum of voided and residual volumes (VV+RV). On the other hand, bladder capacity is calculated by adding the VV (the amount of urine expelled during urination) to the RV (the amount of urine left in the bladder after urination)5. Therefore, the measurement of VV and RV are the keys to deducing other parameters.
Precisely measuring VV in mice during urodynamic tests presents various challenges. The urine of rodents, when physically restrained in a prone position, tends to be drawn downwards through the ventral abdominal wall due to the influence of gravity6. This phenomenon can lead to the absorption of urine by the abdominal fur and skin, which, in turn, underestimates the volume of urine excreted. Considering the small amount of urine produced by mouse, the impact of this absorbance on the accuracy of results is even more pronounced7. Furthermore, in models of SCI, VV is often lower than in normal mice due to the impact of the detrusor sphincter dyssynergia (DSD), which increases the risk of leak point pressures and urine absorption by the fur8. These factors have a significant impact on the results. Therefore, accurate measurement of VV and RV during terminal urodynamic studies in mice is crucial9. Currently, there is a lack of details in the methodologies provided in published literature about how to measure urine volume accurately in mouse models.
Cyanoacrylate adhesive is a type of glue that is commonly used in surgical procedures in human and animal models due to its quick and effective bonding properties10,11,12. This adhesive is particularly useful for closing wounds and lacerations, as it forms a strong and flexible bond when applied to the skin13. Moreover, it can be a great barrier against urine and wetness that may come into contact with fur and wounds11.
In this article, we have developed a novel and cost-effective technique that utilizes cyanoacrylate adhesive to achieve precise results in cystometry and EUS-EMG recordings in awake mice. This method will be beneficial in understanding the underlying causes of bladder dysfunction and devising more effective treatments for LUT disorders.

Autore in primo piano: Metodo urodinamico avanzato per la misurazione precisa delle urine in topi svegli con vescica neurogena

Ottimizzazione delle tecniche urodinamiche del topo per una maggiore precisione 

The goal of this study is to improve the urodynamic technology to increase the accuracy of the urine measurement. Accurate measurement of the urinary parameter awake mice 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 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 another neurodegenerative disease.

Preparazione di catetere ed elettrodi per la cistometria e le registrazioni elettromiografiche dello sfintere uretrale esterno

preparation-catheter-electrodes-for-cystometry-external-urethral

Research

JoVE Journal

Neuroscience

Preparation of Catheter and Electrodes for Cystometry and External Urethral Sphincter Electromyography Recordings

27 Views. Per iniziare, taglia un tubo di polietilene PE-30 da 30 centimetri. Inserire con cautela circa tre quarti dell'ago calibro 25 in un'estremità del tubo. Dopo aver preparato una siringa da 1 millilitro, riempirla con una soluzione sterile di cloruro di sodio allo 0,9% e collegarla all'ago calibro 25.Quindi, infondere delicatamente la soluzione salina per verificare che la punta rotonda sia corretta e che non vi siano perdite dalle estremità dell'ago. P...

Video: Preparazione di catetere ed elettrodi per la cistometria e le registrazioni elettromiografiche dello sfintere uretrale esterno

Optimizing Mouse Urodynamic Techniques for Improved Accuracy 

Accurate measurement of urinary parameters in awake mice is crucial for understanding lower urinary tract (LUT) dysfunction, particularly in conditions like neurogenic bladder post-traumatic spinal cord injury (SCI). However, conducting cystometry recordings in mice presents notable challenges. When mice are in a prone and restricted position during recording sessions, urine tends to be absorbed by the fur and skin, leading to an underestimation of voided volume (VV). The goal of this study was to enhance the accuracy of cystometry and external urethral sphincter electromyography (EUS-EMG) recordings in awake mice. 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. Results show that after applying the cyanoacrylate, the sum of VV and RV remained consistent with the infused saline volume, and there were no wet areas observed post-experiment, indicating successful prevention of urine absorption. Additionally, the method simultaneously stabilized the electrodes connected with the external urethral sphincter (EUS), ensured stable electromyography (EMG) signals, and minimized artifacts caused by the movement of the awakened mouse and manipulation of the experimenter. Methodological details, results, and implications are discussed, highlighting the importance of improving urodynamic techniques in preclinical research.

This protocol provides a guide for waterproofing the skin with cyanoacrylate to prevent urine absorption by fur and skin. It includes instructions for applying the glue to the skin, implanting a bladder catheter, and electrodes for cystometry and external urethral sphincter electromyography recordings in awake mice.

Accurate measurement of urinary parameters in awake mice is crucial for understanding lower urinary tract (LUT) dysfunction, particularly in conditions ...

Ricerca

Neuroscienze

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 1-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.

Surgical Procedure for Bladder Catheter and EUS Electrode Implantation for External Urethral Sphincter Electromyography Recordings

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 electrode's 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.

Procedura chirurgica per l'impianto di catetere vescicale e elettrodo EUS per registrazioni elettromiografiche dello sfintere uretrale esterno

Cystometry and EUS-EMG Recording Preparation in Awake Mice

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.