Abstract：
The therapeutic benefits of photobiomodulation (PBM) in pain management, although well documented, are accompanied by concerns about potential risks, including pain, particularly at higher laser intensities. This study investigated the effects of laser intensity on pain perception using behavioral and electrophysiological evaluations in rats. Our results show that direct laser irradiation of 1000 mW/cm2 to the sciatic nerve transiently increases the frequency of spontaneous firing in the superficial layer without affecting the deep layer of the spinal dorsal horn, and this effect reverses to pre-irradiation levels after irradiation. Interestingly, laser irradiation at 1000 mW/cm2, which led to an increase in spontaneous firing, did not prompt escape behavior. Furthermore, a significant reduction in the time to initiate escape behavior was observed only at 9500 mW/cm2 compared to 15, 510, 1000, and 4300 mW/cm2. This suggests that 1000 mW/cm2, the laser intensity at which an increase in spontaneous firing was observed, corresponds to a stimulus that did not cause pain. It is expected that a detailed understanding of the risks and mechanisms of PBM from a neurophysiological perspective will lead to safer and more effective use of PBM.
摘要：
光生物调节（PBM）在疼痛管理中的治疗益处，虽然有据可查,伴随着对潜在风险的担忧，包括疼痛,特别是在较高的激光强度。这项研究使用行为和电生理评估研究了激光强度对大鼠疼痛感知的影响。我们的结果表明，直接激光照射1000mW/cm2的坐骨神经会短暂增加表层自发放电的频率，而不会影响脊髓背角的深层，这种效应在辐照后逆转到辐照前的水平。有趣的是,激光照射在1000mW/cm2，这导致了增加的自燃，没有提示转义行为。此外，与15、510、1000和4300mW/cm2相比，仅在9500mW/cm2下观察到开始逃逸行为的时间显着减少。这表明，1000mW/cm2，即观察到自发激发增加的激光强度，对应于没有引起疼痛的刺激。预计从神经生理学角度详细了解PBM的风险和机制将导致更安全，更有效地使用PBM。
