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

使用氰基丙烯酸酯皮肤屏障对清醒小鼠进行精确尿动力学测量

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.

作者聚焦：用于神经源性膀胱清醒小鼠精确尿液测量的增强型尿动力学方法

优化小鼠尿动力学技术以提高准确性 

用于膀胱测压和尿道外括约肌电图记录的导管和电极的制备

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

Research

JoVE Journal

Neuroscience

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

32 次观看. 首先，剪一根 30 厘米长的聚乙烯 PE-30 管。小心地将 25 号针头的四分之三插入管子的一端。准备 1 毫升注射器后，用无菌 0.9% 氯化钠溶液填充，并将其连接到 25 号针头。然后，轻轻注入生理盐水以检查针头尖端是否合适且针头末端是否泄漏。准备两根钢丝，每根长 20 厘米。然后，将 25 号针头插入电线的一侧。使用焊料将引脚连接到带状?...

视频: 用于膀胱测压和尿道外括约肌电图记录的导管和电极的制备

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 ...