Mild external heating and reduction in spontaneous contractions of the bladder

Kitney, Darryl G.; Jabr, Rita; Vahabi, Bahareh; Fry, Christopher

Abstract

© 2017 The Authors BJU International © 2017 BJU International Published by John Wiley & Sons Ltd Objectives: To measure the effect of external heating on bladder wall contractile function, histological structure and expression of proteins related to tissue protection and apoptosis. Material and Methods: In vitro preparations of bladder wall and exvivo perfused pig bladders were heated from 37 to 42°C, 46 and 50°C for 15min. Isolated preparations were heated by radiant energy and perfused bladders were heated by altering perfusate temperature. Spontaneous contractions or pressure variations were recorded, as well as responses to the muscarinic agonist carbachol or motor nerve excitation invitro during heating. Tissue histology in control and after heating was analysed using haematoxylin and eosin staining and 4′-6-diamidino-2-phenylindole (DAPI) nuclear labelling. The effects of heating on protein expression levels of (i) heat shock proteins HSP27-pSer82 and inducible-HSP70 and (ii) caspase-3 and its downstream DNA-repair substrate poly-[ADP-ribose] polymerase (PARP) were measured. Results: Heating to 42°C reduced spontaneous contractions or pressure variations by ~70%; effects were fully reversible. There were no effects on carbachol or nerve-mediated responses. Tissue histology was unaffected by heating, and expression of heat shock proteins as well as caspase-3 and PARP were also unaltered. A TRPV1 antagonist had no effect on the reduction of spontaneous activity. Heating to 46°C had a similar effect on spontaneous activity and also reduced the carbachol contracture. Urothelial structure was damaged, caspase-3 levels were increased and inducible-HSP70 levels declined. At 50°C evoked contractions were abolished, the urothelium was absent and heat shock proteins and PARP expression was reduced with raised caspase-3 expression. Conclusions: Heating to 42°C caused a profound, reversible and reproducible attenuation of spontaneous activity, with no tissue damage and no initiation of apoptosis pathways. Higher temperatures caused tissue damage and activation of apoptotic mechanisms. Mild heating offers a novel approach to reducing bladder spontaneous activity.

Citation

Kitney, D. G., Kitney, D., Jabr, R., Vahabi, B., & Fry, C. (2017). Mild external heating and reduction in spontaneous contractions of the bladder. BJU International, 120(5), 724-730. https://doi.org/10.1111/bju.13933

• Journal Article Type: Article
• Acceptance Date: Jun 13, 2017
• Online Publication Date: Jul 20, 2017
• Publication Date: Nov 1, 2017
• Journal: BJU International
• Print ISSN: 1464-4096
• Electronic ISSN: 1464-410X
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 120
• Issue: 5
• Pages: 724-730
• DOI: https://doi.org/10.1111/bju.13933
• Keywords: mild, heating, reduction, bladder, spontaneous, contractions
• Public URL: https://uwe-repository.worktribe.com/output/877949
• Publisher URL: http://dx.doi.org/10.1111/bju.13933
• Additional Information: Additional Information : This is the peer reviewed version of the following article: Kitney, D., Jabr, R., Vahabi, B. and Fry, C. (2017) Mild external heating and reduction of bladder spontaneous contractions. BJU International. ISSN 1464-4096 Available from: http://eprints.uwe.ac.uk/32639, which has been published in final form at http://dx.doi.org/10.1111/bju.13933. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.