Analysis of urethral blood flow by high-resolution laser speckle contrast imaging in a rat model of vaginal distension.

OBJECTIVE: To investigate the feasibility of laser speckle contrast imaging (LSCI) for monitoring urethral blood flow (UBF). MATERIALS AND METHODS: In this study, 18 healthy, virgin female Sprague-Dawley rats aged 8-week-old were used. The animals were divided into the sham group (n = 9) and the vaginal distension (VD) group (n = 9). The sham group underwent one catheterization of the vagina without distension and the VD group underwent one VD. Following the VD or sham treatment for one week, LSCI assessment of urethral blood flow was performed during bladder filling and leak point pressure (LPP) process. RESULTS: During the LPP process, in the VD group, the mean LPP was significantly lower than in the sham group (p < 0.05) and the mean UBF level was also significantly lower than in the sham group (p < 0.05) in the LPP condition. The mean relative change of UBF (Δ Flow) was significantly different between the sham group and VD group. The value was 0.646 ± 0.229 and 0.295 ± 0.19, respectively (p < 0.05). During the bladder filling process, the VD group had a significant lower mean UBF level than the sham group under full bladder conditions (p = 0.008). The mean ΔFlow was also significantly lower than in the sham group. The value was 0.115 ± 0.121 and 0.375 ± 0.127, respectively (p = 0.016). CONCLUSIONS: The results confirmed that LSCI was able to determine UBF in female rats. The VD group had lower baseline UBF and lower increases in UBF during bladder filling and LPP process compared with the sham group.

Morphological and histological changes in the urethra after intraurethral nonablative erbium YAG laser therapy: an experimental study in beagle dogs.

The purpose of this study was to investigate the morphological and histological changes in the urethra in beagle dogs after intraurethral Er:YAG laser irradiation in nonablative mode to confirm the safety of this therapy. Six 2-year-old healthy female virgin beagle dogs (13 ± 1.51 kg) were used in this study. The animals were divided into 2 groups: the sham group, which received sham treatment (n = 3) involving insertion of an intraurethral cannula and laser delivery handpiece into the urethra without laser irradiation, and the experimental group (n = 3), which received intraurethral Er:YAG laser irradiation. The laser irradiation parameters were set according to clinical criteria (4 mm spot size, 1.5 J/cm2, 1.4 Hz, and 4 pulses) in nonablative mode. All animals received three sequential sessions at 4-week intervals. Urethrography and urethroscopy were performed in the 12th week and 13th week, respectively, after the first treatment. After urethroscopy, the animals were sacrificed, and urethral tissue was harvested for histological investigations. All procedures were performed under general anesthesia (40 mg/kg 3% sodium pentobarbital, i.v.). Transforming growth factor ß1 (TGF-ß1) and α-smooth muscle actin (α-SMA) expression levels were measured to evaluate the biochemical characteristics of the scar. Urethral stricture was not found by urethrography or urethroscopy in either group. Urethral epithelium thickness and collagen expression under the urethral mucosa were significantly increased in the experimental group compared with the sham group. However, there were no significant differences in TGF-ß1 and α-SMA expression between the experimental group and sham group (p > 0.05). Urethral stricture is not found in beagle dogs after clinically relevant intraurethral nonablative mode Er:YAG laser irradiation. Proliferation of urethral collagen and the urethral mucosa may be one of the mechanisms by which urine leakage symptoms can be improved.

Verification and Defined Dosage of Sodium Pentobarbital for a Urodynamic Study in the Possibility of Survival Experiments in Female Rat.

OBJECTIVES: To evaluate the effects of pentobarbital dosages on lower urinary tract function and to define an appropriate dosage of sodium pentobarbital that would be suitable for urodynamic studies in which recovery from anesthesia and long term survive were needed for subsequent experiment. METHODS: Twenty-four 8-week-old, female, virgin, Sprague-Dawley rats (200-250 g) were used in this study. Rats in study groups received gradient doses of pentobarbital intraperitoneally, and those in the control group received urethane intraperitoneally. External urethral sphincter electromyography (EUS-EMG) was recorded simultaneously during cystometry and leak point pressure tests. The toe-pinch reflex was used to determine the level of anesthesia. RESULTS: Micturition was normally induced in both the urethane group and 32 mg/kg pentobarbital group. However, in groups of 40 mg/kg or 36 mg/kg pentobarbital, micturition failed to be induced; instead, nonvoiding contractions accompanied by EUS-EMG tonic activity were observed. There were no significant differences in leak point pressure or EUS-EMG amplitude or frequency between the urethane and 32 mg/kg pentobarbital groups. CONCLUSIONS: This study confirmed significant dose-dependent effects of pentobarbital on lower urinary tract function and 32 mg/kg pentobarbital as an appropriate dosage for recovery urodynamic testing, which enable the achievement of expected essential micturition under satisfactory anesthesia in female rats.