Local Application of Ultrasound Attenuates Neuropathic Allodynia and Proinflammatory Cytokines in Rats After Thoracotomy.

Abstract

BACKGROUND AND OBJECTIVES:

We aimed to investigate the effect of therapeutic ultrasound (TU) on pain sensitivity and the concentration inflammatory cytokines in a thoracotomy rat model.

METHODS:

Rats were distributed randomly into 4 groups: (1) sham operated, (2) thoracotomy and rib retraction (TRR), (3) TRR rats that received TU (TRR + TU-1), and (4) TRR rats that received TU with the ultrasound turned off (TRR + TU-0). Ultrasound was set at 1-MHz frequency (1.0-W/cm intensity and 100% duty cycle for 5 minutes), began on postoperative day (POD) 10, and then continued once per day, 5 days a week for 3 weeks.

RESULTS:

The TRR and TRR + TU-0 rats encountered tactile hypersensitivity from PODs 10 to 28. Mechanical withdrawal thresholds were increased (all P < 0.05) following 5 days of TU, but thresholds remained significantly lower than baseline values. Therapeutic ultrasound increased the subcutaneous, but not body temperature. All groups receiving TRR demonstrated an increase in concentration of interleukin 1β and tumor necrosis factor α (TNF-α) on POD 14; however, the rise in TNF-α concentration was less in the TU-treated group than in the others. The decrease in concentration was greatest in the TRR + TU-1 group and similar between the TRR and TRR + TU-0 groups.

CONCLUSIONS:

Mechanical allodynia was partially resolved with TU. Tissue temperature increased with ultrasound, while TU restricted the up-regulation of interleukin 1β and TNF-α around the injured intercostal nerve.

• Authors: Ching-Hsia Hung, Chong-Chi Chiu, Chen-Chih Liu, Yu-Wen Chen
• Journal: Regional anesthesia and pain medicine (Reg Anesth Pain Med) Vol. 43 Issue 2 Pg. 193-199 (Feb 2018) ISSN: 1532-8651 [Electronic] England
• PMID: 29278606 (Publication Type: Journal Article)

Chemical References

• Cytokines
• IL1B protein, rat
• Inflammation Mediators
• Interleukin-1beta
• Tumor Necrosis Factor-alpha

Topics

• Animals
• Cytokines (metabolism)
• Disease Models, Animal
• Hyperalgesia (etiology, metabolism, physiopathology, prevention & control)
• Inflammation Mediators (metabolism)
• Intercostal Nerves (injuries, metabolism, physiopathology)
• Interleukin-1beta (metabolism)
• Male
• Neuralgia (etiology, metabolism, physiopathology, prevention & control)
• Pain Measurement
• Pain Threshold (drug effects)
• Pain, Postoperative (etiology, metabolism, physiopathology, prevention & control)
• Peripheral Nerve Injuries (etiology, metabolism, physiopathology, therapy)
• Rats, Sprague-Dawley
• Thoracotomy (adverse effects)
• Time Factors
• Tumor Necrosis Factor-alpha (metabolism)
• Ultrasonic Therapy