Peier Franziska, Mouthon Michael, De Pretto Michael, Chabwine Joelle Nsimire
Laboratory for Neurorehabilitation Science, Medicine Section, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland.
Neurology Division, Department of Internal Medicine, Fribourg-Cantonal Hospital, Fribourg, Switzerland.
Front Neurosci. 2024 Jan 15;17:1287233. doi: 10.3389/fnins.2023.1287233. eCollection 2023.
Pain is a major public health problem worldwide, with a high rate of treatment failure. Among promising non-pharmacological therapies, physical exercise is an attractive, cheap, accessible and innocuous method; beyond other health benefits. However, its highly variable therapeutic effect and incompletely understood underlying mechanisms (plausibly involving the GABAergic neurotransmission) require further research. This case-control study aimed to investigate the impact of long-lasting intensive endurance sport practice (≥7 h/week for the last 6 months at the time of the experiment) on the response to experimental cold-induced pain (as a suitable chronic pain model), assuming that highly trained individual would better resist to pain, develop advantageous pain-copying strategies and enhance their GABAergic signaling. For this purpose, clinical pain-related data, response to a cold-pressor test and high-density EEG high (Hβ) and low beta (Lβ) oscillations were documented. Among 27 athletes and 27 age-adjusted non-trained controls (right-handed males), a category of highly pain-resistant participants (mostly athletes, 48.1%) was identified, displaying lower fear of pain, compared to non-resistant non-athletes. Furthermore, they tolerated longer cold-water immersion and perceived lower maximal sensory pain. However, while having similar Hβ and Lβ powers at baseline, they exhibited a reduction between cold and pain perceptions and between pain threshold and tolerance (respectively -60% and - 6.6%; -179.5% and - 5.9%; normalized differences), in contrast to the increase noticed in non-resistant non-athletes (+21% and + 14%; +23.3% and + 13.6% respectively). Our results suggest a beneficial effect of long-lasting physical exercise on resistance to pain and pain-related behaviors, and a modification in brain GABAergic signaling. In light of the current knowledge, we propose that the GABAergic neurotransmission could display multifaceted changes to be differently interpreted, depending on the training profile and on the homeostatic setting (e.g., in pain-free versus chronic pain conditions). Despite limitations related to the sample size and to absence of direct observations under acute physical exercise, this precursory study brings into light the unique profile of resistant individuals (probably favored by training) allowing highly informative observation on physical exercise-induced analgesia and paving the way for future clinical translation. Further characterizing pain-resistant individuals would open avenues for a targeted and physiologically informed pain management.
疼痛是全球范围内一个主要的公共卫生问题，治疗失败率很高。在有前景的非药物疗法中，体育锻炼是一种有吸引力、廉价、可及且无害的方法；它还有其他健康益处。然而，其治疗效果高度可变且潜在机制尚未完全明了（可能涉及γ-氨基丁酸能神经传递），需要进一步研究。本病例对照研究旨在调查长期高强度耐力运动训练（在实验时的过去6个月中≥7小时/周）对实验性冷诱导疼痛（作为一种合适的慢性疼痛模型）反应的影响，假设训练有素的个体对疼痛的抵抗力更强，会形成有利的疼痛应对策略并增强其γ-氨基丁酸能信号传导。为此，记录了临床疼痛相关数据、对冷加压试验的反应以及高密度脑电图的高β（Hβ）和低β（Lβ）振荡。在27名运动员和27名年龄匹配的未训练对照者（右利手男性）中，识别出一类高度耐痛的参与者（大多为运动员，占48.1%），与不耐痛的非运动员相比，他们对疼痛的恐惧较低。此外，他们能耐受更长时间的冷水浸泡，且感觉到的最大感觉疼痛较低。然而，尽管他们在基线时的Hβ和Lβ功率相似，但与不耐痛的非运动员中观察到的增加情况相反（分别增加21%和14%；增加23.3%和13.6%），他们在冷觉与痛觉之间以及痛阈与痛耐之间的功率出现了降低（分别降低60%和6.6%；降低179.5%和5.9%；标准化差异）。我们的结果表明，长期体育锻炼对疼痛抵抗力和疼痛相关行为有有益影响，并能改变大脑的γ-氨基丁酸能信号传导。根据目前的知识，我们提出γ-氨基丁酸能神经传递可能会呈现多方面的变化，需要根据训练情况和稳态环境（例如在无痛与慢性疼痛状态下）进行不同的解读。尽管本研究存在样本量有限以及缺乏急性体育锻炼下直接观察等局限性，但这项前瞻性研究揭示了耐痛个体的独特特征（可能受训练的青睐），使得能够对体育锻炼诱导的镇痛进行极具信息量的观察，并为未来的临床转化铺平了道路。进一步刻画耐痛个体将为有针对性的、基于生理学知识的疼痛管理开辟道路。
