Ultrasound induces contraction of the bladder smooth muscle.
OBJECTIVE
To investigate whether the treatment of overt postpartum urinary retention (PUR) with low-intensity pulsed ultrasound (LIPUS) was clinically effective and whether LIPUS could accelerate bladder smooth muscle (BSM) contraction by opening the L-type calcium channels and activating the Ca(2+) signaling pathway.


METHODS
Records of 136 patients undergoing PUR were retrospectively reviewed in two different groups for LIPUS and neostigmine between from 2014 to July 2015. The rats BSM strips in vitro were irradiated by LIPUS. The contraction frequency and amplitude were recorded with BL-410F biological experimental system. The BSM cells were constructed and identified by α-actin-specific antibody staining, and the intracellular Ca(2+) concentration was analyzed by flow cytometry.


RESULTS
The clinical trial indicated that LIPUS had potential therapeutic effect on PUR (80.6 vs. 64.1 %, p < 0.05), and the BSM strip contractility was increased by LIPUS (p < 0.001), and the concentration of Ca(2+) was markedly enhanced by about twofold than that without LIPUS exposure (p < 0.01). Besides, nimodipine could suppress the contraction of BSM and the concentration of intracellular Ca(2+) which was caused by ultrasound.


CONCLUSIONS
The results suggested LIPUS had potential therapeutic effect on PUR and the Ca(2+) signaling pathway was involved in the mechanism. The ultrasound irradiation may provide a new method for PUR therapy.
Department of Obstetrics and Gynecology, The Second Affiliated Hospital, Chongqing Medical University, 74 Linjiang Road, Yuzhong District, Chongqing, 400010, China.
Yan
Y
Ren
Department of Obstetrics and Gynecology, The Second Affiliated Hospital, Chongqing Medical University, 74 Linjiang Road, Yuzhong District, Chongqing, 400010, China.
Yi
Y
Zhu
Department of Obstetrics and Gynecology, The Second Affiliated Hospital, Chongqing Medical University, 74 Linjiang Road, Yuzhong District, Chongqing, 400010, China.
Li
L
Liu
Department of Obstetrics and Gynecology, The Second Affiliated Hospital, Chongqing Medical University, 74 Linjiang Road, Yuzhong District, Chongqing, 400010, China.
Tinghe
T
Yu
Department of Obstetrics and Gynecology, The Second Affiliated Hospital, Chongqing Medical University, 74 Linjiang Road, Yuzhong District, Chongqing, 400010, China. xffdoctor@163.com.
Xiaojing
X
Dong
D000818:Animals; D016009:Chi-Square Distribution; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D009119:Muscle Contraction / Q000502:physiology*; D009130:Muscle, Smooth / Q000187:drug effects / Q000528:radiation effects; D009388:Neostigmine / Q000627:therapeutic use; D049590:Postpartum Period; D011247:Pregnancy; D011270:Pregnancy, Animal; D051381:Rats; D017207:Rats, Sprague-Dawley; D012189:Retrospective Studies; D016896:Treatment Outcome; D014464:Ultrasonic Therapy / Q000379:methods*; D000069453:Ultrasonic Waves; D016055:Urinary Retention / Q000175:diagnosis / Q000628:therapy*
D009388:Neostigmine
Bladder smooth muscle; L-type calcium channels; Low-intensity pulsed ultrasound; Postpartum urinary retention