title: Nerve conduction block in diabetic rats using high-intensity focused ultrasound for analgesic applications.
abstract: BACKGROUND
  Nerve conduction block using high-intensity focused ultrasound (HIFU) has been conducted with nerves of mixed fibres in normal animal models. This study tested the feasibility and safety of HIFU for sensory nerve conduction block in diabetic neuropathic nerves to determine its potential for pain relief.
  
  
  METHODS
  Diabetes was induced in Sprague-Dawley rats using streptozotocin, and HIFU at 2.68 MHz was used for the block. This study consisted of two sections, in vitro and in vivo. For the in vitro experiments, the entire contiguous sciatic-sural nerves were obtained. Compound action potentials and sensory action potentials were recorded in the sciatic and sural nerves, respectively. For the in vivo experiments, compound muscle action potentials (CMAPs) were recorded from the gastrocnemius muscles. All data were expressed as median (range).
  
  
  RESULTS
  The in vitro results showed that HIFU temporarily inhibited sensory action potentials of the control and diabetic rat nerves to 33.9 (8.2) and 14.0 (10.7)% of the baseline values, respectively, whereas the compound action potentials were suppressed to 53.6 (8.4) and 76.2 (7.5)% of baseline, respectively. The in vivo results showed that HIFU acutely blocked CMAPs to 32.9 (12.6) and 19.9 (10.9)% of baseline in control and diabetic rat nerves, respectively. Measurements of CMAPs and histological exanmination were used for indirect assessment of the safety of the HIFU technique.
  
  
  CONCLUSIONS
  High-intensity focused ultrasound safely and reversibly suppressed nerve conduction in diabetic rat nerves when the stimulation parameters were appropriate. The results suggest that HIFU may have potential to block sensory nerves reversibly and provide peripheral pain relief.
authors.affiliation: Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Zhunan, Taiwan.
authors.forename: Y-F
authors.initials: YF
authors.lastname: Lee
authors.affiliation: Department of Neurology, National Cheng Kung University Hospital, Tainan, Taiwan.
authors.forename: C-C
authors.initials: CC
authors.lastname: Lin
authors.affiliation: Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Zhunan, Taiwan.
authors.forename: J-S
authors.initials: JS
authors.lastname: Cheng
authors.affiliation: Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Zhunan, Taiwan gschen@nhri.org.tw.
authors.forename: G-S
authors.initials: GS
authors.lastname: Chen
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D003921:Diabetes Mellitus, Experimental; D003929:Diabetic Neuropathies / Q000601:surgery*; D005240:Feasibility Studies; D057086:High-Intensity Focused Ultrasound Ablation / Q000379:methods*; D008297:Male; D009407:Nerve Block / Q000379:methods*; D009431:Neural Conduction / Q000502:physiology*; D010146:Pain / Q000601:surgery*; D059408:Pain Management / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012584:Sciatic Nerve / Q000601:surgery; D013497:Sural Nerve / Q000601:surgery
keywords: diabetic neuropathic nerves; high-intensity focused ultrasound; rat; sensory nerve conduction block