| Part ? Methodological Study on Recording Urethral Pressure Profiles using a Water-perfusion Catheter System in Female RatsObjective:Urethral pressure profile (UPP) and abdominal leak point pressure (ALPP) as well as external urethral sphincter electromyography and videourodynamic analyses are the important method for evaluating urethral function in humans. However, UPP recording in female rats, a widely used animal model, is challenging due to their small body sizes. This study reports a novel method for recording UPP in female rats.Methods:A total of 17 health female Sprague-Dawley (SD) rats of 250-280 g were studied. All operations were performed under intraperitoneal anesthesia with pentobarbital. A self-making 3F single hole UPP recording catheter and an urodynamic equipment (Laborie, Canada) were used for urodynamic study. The ALPP was determined firstly via a supra-pubic tube, and then UPP recording. Parameters setting in UPP recording as follows: The bladder pressure was maintained at 5 cmH2O, saline was infused at 0.5 mL/min, the pressure of perfusion pump was maintained at 150 cmH20, and the catheter was withdrawn at 1 mm/s by the mechanical drawer. UPP recordings were performed with the lateral water-perfusion hole facing 3-,6-,9-, and 12-o'clock positions in a randomized sequence in 10 rats. These recordings were repeated in a randomized sequence to assess data reproducibility in 9 rats. At the same time, the correlation between ALPP and maximum urethral closure pressure (MUCP) at the 4 directions of the urethra were studied. Data were tested for normality using the Kolmogorov-Smirnov test. If the two data were normal distribution, the data were compared with the t test. If not, then the non parametric Kruskal-Wallis test was used. Differences between the primary and repeated measurements of the MUCP and functional profile length (FUL) were tested using paired-samples t tests. The consistency of the UPP measurements between the primary and repeated recording was assessed by calculating intra-class correlation coefficients (ICCs). The correlation of ALPP and MUCP at 4 directions was analyzed by Pearson correlation.Results:The ALPP was determined in 14 rats. The other 3 rats were excluded because of death. The mean ALPP of the rats was 64.39±20.29 cmH2O. The UPP curves were recorded at 4 directions of urethra in 10 rats. The FUL at 3,6,9,12-o'clock directions were 12.90±1.20 mm,16.70±1.95 mm,13.90±2.42 mm,11.60±0.97 mm, respectively and MUCP at 3,6,9,12-o'clock directions are 38.70±11.85 cmH20,33.90±1.82 cmH2O, 37.40±11.95 cmH20,71.90±23.01 cmH20, respectively. FUL at 6-o'clock and MUCP at 12-o'clock was found to be significantly greater than in other 3 directions (P<0.05). The 3-and 9-o'clock positions exhibited similar MUCP (P= 0.702) and FUL (P=0.540) values. The UPP recordings were repeated in 9 rats. FUL and MUCP at 4 directions of repeated UPP recordings demonstrated no significant difference compared with the primary recordings. The ICCs of the MUCPs between the primary and repeat recordings ranged from 0.838 to 0.960 with excellent reproducibility and the FULs ranged from 0.672 to 0.844 with good reproducibility in the present study, demonstrating the high reproducibility of UPP recordings obtained using the present method. In addition, there was no linear correlation between ALPP and MUCP at 4 directions of urethra.Conclusion:The UPP recording with a modified method on basis of a water-perfusion catheter system is feasible and repeatable in female rats, which would be likely to enhance the usefulness of the female rat model for in vivo investigation of urethral function as well as getting better understanding of urinary continence function mechanism in human being. At the same time, this study showed that the UPP recording of the female rats had obviously directional variation, UPP in the anterior and posterior wall of urethra were asymmetrical, and the two sides were symmetrical.Part ? Effects of Anesthetic Drugs on the Urethral Pressure Profiles in Female RatsObjective:To investigate the effects of different anesthetic drugs and depth on the urethral pressure profiles (UPP) in female rats, and to explore the appropriate selection of anesthetic drugs.Materials and Methods:Thirty healthy female Sprague-Dawley (SD) rats of 250-300 g were used in this study. A self-making 3F single hole UPP recording catheter and an urodynamic equipment (Laborie, Canada) were used for urodynamic study. Parameters setting in UPP recording as follows:The bladder pressure was maintained at 5 cmH20, saline was infused at 0.5 mL/min, the pressure of perfusion pump was maintained at 150 cmH20, and the catheter was withdrawn at 1 mm/s by the mechanical drawer. Grouping and processing were as follows:Group 1:6 adult female rats were given doses of pentobarbital (20-25mg/Kg) to produce light anesthesia. Group 2:12 adult female rats were given doses of pentobarbital (35mg/Kg) to produce anesthesia. Group 3:12 adult female rats were given doses of urethane (1.2g/Kg) to produce anesthesia. UPP curves were recorded with the lateral hole facing the 6- or 9-o'clock position. Then, all rats, except light anesthesia rats, were bred and observed for the long-term survival. The differences on functional urethral length (FUL), maximum urethral close pressure (MUCP), and mortality were compared between different groups. Data were tested for normality using the Kolmogorov-Smirnov test. If the two data were normal distribution, the data were compared with the t test. If not, then the non parametric Kruskal-Wallis test was used. The survival curve was drawn by Kaplan-Meier method, and the difference between survival curves was compared by Log-rank test.Results:In group of light anesthesia, MUCP values at the 6- and 9-o'clock positions were 67.40±05.51 cmH2O and 68.80±17.30 cmH2O, respectively. FUL values at the 6- and 9-o'clock positions were 21.40±0.89 mm and 21.00±02.92 mm, respectively. In group of pentobarbital, MUCP values at the 6- and 9-o'clock positions were 57.70±13.90 cmH20 and 69.66±16.22 cmH20, respectively. FUL values at the 6- and 9-o'clock positions were 17.27±2.58 mm and 15.94±1.81 mm, respectively. In group of urethane, MUCP values at the 6- and 9-o'clock positions were 50.22±08.74 cmH2O and 54.33±08.77 cmH2O, respectively. FUL values at the 6- and 9-o'clock positions were17.22±2.16 mm and 15.50±1.69 mm, respectively. Comparison the effects of different depth of anesthesia on UPP:Urethane anesthesia produced lowest MUCP and FUL values in all groups. There were significant differences of MUCP values at the 6-o'clock positions, and FUL values at the 6- and 9-o'clock positions between urethane and light anesthesia. The MUCP value at the 6-o'clock position in pentobarbital anesthesia group also declined, but the decrease was less, compared with the light anesthesia group, the difference was not statistically significant, but the MUCP value at the 9-o'clock position did not decline. However, there were significant differences of FUL values at the 6- and 9-o'clock positions between pentobarbital and light anesthesia. Comparison the effects of different anesthetic drugs on UPP:Compared with pentobarbital, urethane anesthesia measured MUCP at the 9-o'clock positions was significant lower (P=0.028), but the difference was not statistically significant on MUCP at the 6-o'clock positions, and FUL at the 6-and 9-o'clock positions. In addition, the postoperative mortality was significantly higher in urethane group than in pentobarbital (P=0.042).Conclusions:Different anesthetic and anesthesia depth had different effects on measurement results of UPP values. Compared with urethane, pentobarbital produced lower postoperative mortality, as well as higher MUCP and FUL without significance, which was closer to the normal physiological state. It is more appropriate to choice pentobarbital for anesthetized UPP studies after considering the effects of anesthetics on UPP and mortality.Part ? The Association Between Urethral Pressure Profile and Urethral Histological Structure in Female RatsObjective:Urethral pressure profile (UPP) has been one of the most important methods in the study of urethral function for more than half a century, but is also a controversial method. The reason is that the method of UPP recording has some defects, and more important is that the physiological meaning of UPP is lack of correct understanding by now. In this study, we want to investigate the urethral histological structure in female rats, and to explore the relationship between the distribution of UPP curve and urethral histological structure, and clarify the physiology of UPP.Methods:A total of 8 health female Sprague-Dawley (SD) rats of 235-300 g were studied. All operations were performed under intraperitoneal anesthesia with pentobarbital. A self-making 3F single hole UPP recording catheter and an urodynamic equipment (Laborie, Canada) were used for urodynamic study. Parameters setting in UPP recording as follows: In order to better reveal the proximal urethra, the bladder pressure is set to 0cmH2O, saline was infused at 0.5 mL/min, the pressure of perfusion pump was maintained at 150 cmH2O, and the catheter was withdrawn at 1 mm/s by the mechanical drawer. UPP recordings were performed with the lateral water-perfusion hole facing 3-,6-,9-, and 12-o'clock positions in a randomized sequence in each rat, and the area under the UPP curves were calculated. After the UPP recordings, the urethra of female rat was used for pathological examination. Masson's Trichrome staining and Immunohistochemistry staining were performed. The functional urethral length (FUL) and maximum urethral closure pressure (MUCP) were recorded. SPSS Statistics 22 software was used for statistical data. The correlation of UPP and urethral histological structure was analyzed by Pearson correlation.In all cases, a P<0.05 was considered statistically significant.Results:The FUL at 3-,6-,9-, and 12-o'clock positions were 17.00±1.51,18.50±1.77, 17,38±1.30, and 14.75±2.31mm, respectively, and MUCP at 3-,6-,9-, and 12-o'clock positions were 53.00±17.96,46.00±12.60,51.50±10.54, and 82.50±28.68cmH2O, respectively. The FUL at the 6-o'clock position was significantly longer than those at the other 3 positions, the difference was statistically significant (P<0.05), and the MUCP at the 12-o'clock position was significantly greater than those at the other 3 positions, the difference was statistically significant (P<0.05). Similar MUCP (P>0.05) and FUL (P>0.05) values were detected at the 3- and 9-o'clock positions. The area under the UPP curve at 3-, 6-,9-, and 12-o'clock positions were 0.6254±0.0021mm2,0.6510±0.067mm2, 0.6057±0.0032mm2,0.7634±0.0078mm2, respectively. By analyzing the histological characteristic of the three segments of urethra in female rats, the proximal urethra contained only smooth muscle, and the middle urethra contained smooth and striated muscle. There was only a small amount of striated and smooth muscle in distal urethra. The proximal urethra contained only smooth muscle, but the corresponding urethral pressure was very low, which indicated that the smooth muscle was not the key histological component for UPP. The high-pressure zone of UPP existed in the middle urethra with striated muscle distribution. However, the results of linear correlation analysis between UPP and urethral structure showed that there was no linear correlation between UPP and striated muscle. By analyzing the histological structure at the 4 directions of urethra, the striated muscle showed circular, longitudinal, and oblique distribution in the urethra wall.The striated muscle was thick on the anterior urethra wall, and the weakest on the posterior urethral wall. However, the thickness was similar on the two side of the urethral wall. There were a lot of same shape submucosal sinusoids on the anterior and two side walls of the urethra, and large vertical submucosal sinusoids on the posterior urethral wall. The characteristic of the corresponding urethral pressure profile was that the urethral pressure on the anterior urethra wall was the highest, on the posterior urethral wall was lowest. However, the urethral pressure was symmetrical on the two side of the urethral wall. The above results showed that the regular distribution of urethral tissue structure was the histological basis of the determination of UPP.Conclusion:UPP is a reflection of the biological characteristics of the specific tissue in the wall of the urethra. Determine the characteristics of UPP have the following two points:the non-uniform distribution of striated muscle in each direction and segments of urethra, and the special distribution of the submucosal sinusoids of the urethra. However, there was no significantly correlation between the smooth muscle and UPP.Part ? Analysis of Influence Factors and Application of Urethral Pressure Profile in Female RatsObjective:To investigate the possible effects of pudendal nerve and urethral vessel on urethral pressure profile (UPP) and to explore the application of urethral pressure profile in female rats.Methods:Twelve health female Sprague-Dawley (SD) rats of 250-280 g were used in this study. All operations were performed under intraperitoneal anesthesia with pentobarbital. A self-making 3F single hole UPP recording catheter and an urodynamic equipment (Laborie, Canada) were used for urodynamic study. Parameters setting in UPP recording as follows: The bladder pressure was maintained at 5 cmH2O, saline was infused at 0.5 mL/min, the pressure of perfusion pump was maintained at 150 cmH20, and the catheter was withdrawn at 1 mm/s by the mechanical drawer. Grouping and processing were as follows:Group 1: Pudendal nerve transection anesthetized with pentobarbital was performed bilaterally in 6 female rats. Abdominal leak point pressure (ALPP) and UPP curves with the lateral hole facing the 6- or 9-o'clock position were determined before and after bilateral pudendal nerve transection. Group 2:By blocking the aortaventralis indirectly blocking the blood vessel of the urethra, aortaventralis occlusion was performed in 6 female rats anesthetized with pentobarbital. ALPP and UPP curves with the lateral hole facing the 6- or 9-o'clock position were determined before and after occlusion of the aortaventralis. Functional urethral length (FUL), maximum urethral close pressure (MUCP), and ALPP were analyzed. SPSS Statistics 22 software was used for statistical data. Data were tested for normality using the Kolmogorov-Smirnov test. If the two data were normal distribution, the data were compared with the t test. If not, then the non parametric Kruskal-Wallis test was used. In all cases, a P<0.05 was considered statistically significant.Results:Before and after bilateral pudendal nerve transection, the mean ALPP were 80.80±12.87cmH2O, and 28.64±11.63cmH2O, respectively; The MUCP values at 6-o'clock were 54.80±14.02cmH2O, and 22.40±06.19cmH2O, respectively; The FUL values at 6-o'clock were 18.10±1.38mm, and 17.50±1.32mm, respectively. The MUCP values at 9-o'clock were 69.80±11.67cmH2O, and 36.60±08.20cmH2O, respectively; The FUL values at 9-o'clock were 15.90±1.14mm, and 15.40±1.78mm, respectively. Therefore, after bilateral pudendal nerve transection, ALPP and MUCP values were significantly decreased (P<0.O5), while there was no significant difference of FUL (P>0.05). Before and after occlusion of the aortaventralis, the mean ALPP were 68.30±18.70cmH2O, and 36.48±11.85cmH2O, respectively; The MUCP values at 6-o'clock were 62.30±26.31cmH2O, and 36.20±22.38cmH2O, respectively; The FUL values at 6-o'clock were 16.62± 1.46mm, and 16.20±2.73mm, respectively. The MUCP values at 9-o'clock were 72.87±25.69cmH2O, and 40.50±22.29cmH2O, respectively; The FUL values at 9-o'clock were 15.30±1.84mm, and 15.54±2.71mm, respectively. After occlusion of the aortaventralis, ALPP decreased significantly (P=0.009). The MUCP values at the 6- and 9-o'clock positions had a larger decline, but the difference was not statistically significant There was also no significant difference of FUL (P>0.05).Conclusions:There was a significant effect on urethral pressure profile after bilateral pudendal nerve transection and occlusion of urethral vessel By comparing with ALPP, the UPP can also be effective in response to changes in urethral function. |
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