Effects of Electroacupuncture at Bl33 on Detrusor Smooth Muscle Activity in a Rat Model of Urinary Retention

Abstract

BackgroundDetrusor smooth muscle (DSM) underactivity may lead to urinary retention (UR). Electroacupuncture (EA) at BL33 may be effective in improving DSM contractions.ObjectivesThis study aimed to investigate: (1) the effect of EA at BL33; and (2) the effect of different manipulation methods at BL33 on the modulation of DSM contractions in UR rats.Methods30 male Sprague-Dawley rats were anaesthetised with urethane and modelled by urethral outlet obstruction. First, 2 Hz EA at BL33, SP6 and LI4 wasrandomly applied to the UR rats for 5 min to observe the immediate effects (n=10); second, manual acupuncture (MA) (n=10) and 100 Hz EA (n=10) were applied with the same programme. DSM electromyography (EMG) and cystometrogram data were evaluated.Results(1) 2 Hz EA at BL33 and SP6 significantly increased DSM discharging frequency (0.80±0.10 Hz, P<0.001, and 0.22±0.14 Hz, P=0.038), shortened micturation intervals (65.67±20.65 s, P=0.008, and 35.62±15.84 s, P=0.042), prolonged the duration of voiding (2.13±0.61 s, P=0.005, and 0.47±0.16 s, P=0.015), and reduced residual pressure (−0.91±0.31 mmHg, P=0.019, and −0.66±0.27 mmHg, P=0.046). EA at LI4 was not associated with any functional effects (P>0.05). Compared with SP6, EA at BL33 had greater positive effects on DSM discharging frequency, duration of discharging, and duration of voiding (all P<0.05). (2) No statistically significant differences were shown between MA, 2 Hz EA and 100 Hz EA interventions when stimulating at BL33, SP6 or LI4.ConclusionsEA at BL33 improved DSM contractions to a greater degree than EA at SP6 or LI4. There were no differences in effect when stimulating using 2 Hz EA, 100 Hz EA and MA.

Effect of Electroacupuncture on Bladder Dysfunction via Regulation of MLC and MLCK Phosphorylation in a Rat Model of Type 2 Diabetes Mellitus

“…Relevant studies have found that acupuncture can activate the afferent nerve fibers of the dorsal root of the spinal cord [ 45 ]. Since the micturition center of BL33 and SP6 is located in the same segment, EA at these acupoints may activate sacral afferent nerve fibers to enhance bladder detrusor smooth muscle contraction [ 46 ]. Previous studies have reported that an increased bladder weight is correlated with increased bladder threshold capacity and residual urine [ 47 ].…”

“…SP6 is located 10 mm above the tip of the medial malleolus in rats. Since rats have only three pairs of posterior sacral foramina, we located the BL33 point at the second posterior sacral foramen [ 18 , 26 ]. Disposable sterile stainless steel acupuncture needles (0.25 mm × 25 mm; Cofoe Medical Technology Co., Ltd., Hunan, China) were inserted bilaterally at BL33 to a depth of approximately 15 mm and vertically inserted at SP6 to a depth of approximately 3 mm bilaterally.…”

“…Electroacupuncture (EA) is based on conventional acupuncture treatment, wherein an electric current is passed through a specific electrical device to stimulate the body's acupoints. In clinical trials, BL33 (Zhongliao) and SP6 (Sanyinjiao) are the two most commonly used acupoints to treat bladder dysfunction [ 18 ]. In addition, a related animal study has shown that a 2-Hz EA stimulation at BL33 can enhance the detrusor smooth muscle contraction and improve voiding dysfunction [ 18 ].…”

“…In clinical trials, BL33 (Zhongliao) and SP6 (Sanyinjiao) are the two most commonly used acupoints to treat bladder dysfunction [ 18 ]. In addition, a related animal study has shown that a 2-Hz EA stimulation at BL33 can enhance the detrusor smooth muscle contraction and improve voiding dysfunction [ 18 ]. From a neurophysiological perspective, the muscle tissues at BL33 and SP6 are dominated by the same segment (S2–S4) of the spinal cord micturition center [ 19 ].…”

Effects of electroacupuncture on bladder dysfunction and the expression of PACAP38 in a diabetic rat model

“…Electroacupuncture (EA) is an important method to prevent and treat DM and its complications ( Yao et al, 2021 ). BL23, BL33, and SP6 are acupoints widely studied in DM treatment (its common chronic complication) and bladder dysfunction ( Liu et al, 2017 ; Feng et al, 2018 ). BL28 corresponds to sacral vertebrae S2 and S3 levels; EA stimulation of the sacral vertebrae can inhibit an overactive bladder ( Feng et al, 2013 ).…”