[Moxibustion improves bladder excitability by up-regulating ATP-sensitive potassium channel in rats with detrusor hyperreflexia].

OBJECTIVES

To observe the effect of ginger-salt-partitioned moxibustion on bladder excitability and bladder ATP-sensitive potassium (KATP) channel in detrusor hyperreflexia (DH) rats.

METHODS

Female SD rats were randomly divided into sham operation, model, moxibustion and inhibition groups (n=8 in each group). Thorax (T) 10 spinal cord transection was performed by surgery. Ginger-salt-partitioned moxibustion was applied to "Shenque" (CV8) for 20 min, once daily for 14 consecutive days. Rats of the inhibition group received intraperitoneal injection of glibenclamide (10 μg/kg) 15 min before moxibustion intervention. Urodynamic tests were performed after treatment. The detrusor myoelectric activities (frequency and amplitude) were recorded by using Powerlab multichannel physiograph. Primary detrusor muscle cells were extracted and identified by immunofluorescence staining. The changes in KATP channel currents and intracellular Ca2+ dynamics of bladder detrusor muscle cells were detected using patch-clamp and calcium imaging techniques.

RESULTS

Compared with the sham operation group, the first leakage pressure (P<0.000 1) and the leakage point pressure after stable urination (P<0.01) were increased, the urination interval was shortened (P<0.001), the bladder compliance was decreased (P<0.01), the amplitude and median frequency of detrusor electromyography during urination were significantly decreased (P<0.000 1), the current density of KATP channel was decreased (P<0.000 1), and the ratio of intracellular relative calcium fluorescence change was increased (P<0.000 1). After the treatment and compared with the model group, the above-mentioned indicators in the moxibustion group were all reversed (P<0.05, P<0.000 1). Compared with moxibustion group, all the above indicators in the inhibitor group were reversed (P<0.05, P<0.01, P<0.001, P<0.000 1).

CONCLUSIONS

Ginger-salt-partitioned moxibustion can increase the leakage point pressure, prolong the urination interval, improve bladder compliance, and increase the amplitude and median frequency of detrusor contraction during urination in DH rats, which may be associated with increasing the current density of KATP channel, improving the efficiency of channel opening, promoting the outflow of K+ and cell membrane hyperpolarization, reducing intracellular Ca2+ concentration, thereby inhibiting bladder contraction.