Department of Locomotive Rehabilitation Science, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
Department of Rehabilitation, Juzenkai Hospital, Nagasaki, Japan.
Phys Ther. 2021 Feb 4;101(2). doi: 10.1093/ptj/pzaa211.
The biological mechanisms of cryotherapy for managing acute pain remain unclear. Additionally, it is unknown whether the effectiveness of cryotherapy depends on the applied temperature. This study aimed to clarify the biological effects of cryotherapy and to examine the therapeutic effects of cryotherapy applied at different temperatures in rats.
This was an experimental study using a rat knee joint arthritis model. Thirty-five Wistar rats were randomly divided into arthritis (AR), arthritis with 5°C cryotherapy (CR-5), arthritis with 10°C cryotherapy (CR-10), and sham-arthritis control (CON) groups. Arthritis was induced by injecting a mixture of kaolin/carrageenan into the right knee joint. Cryotherapy was applied for 7 days starting the day after injection by immersing the right knee joint in 5°C or 10°C water. Joint transverse diameter, pressure pain threshold, and pain-related behaviors were assessed for 7 days. The number of CD68-positive cells in the knee joint and the expression of calcitonin gene-related peptide in the spinal dorsal horn 8 days after injection were analyzed by immunohistochemical staining.
Improvements in transverse diameter, pressure pain threshold, and pain-related behaviors were observed in the CR-5 and CR-10 groups on the 3rd day compared with the AR group. The number of CD68-positive cells and the expression of calcitonin gene-related peptide in the CR-5 and CR-10 groups were significantly decreased compared with the AR group. There were no significant differences in all results between the CR-5 and CR-10 groups.
Cryotherapy can ameliorate inflammatory pain through reduction of synovium and central sensitization. Additionally, the effects of cryotherapy lower than 10°C are observed independent of applied temperature.
Cryotherapy may be beneficial as a physical therapy modality for pain and swelling management in the acute phase of inflammation. Translational human study is needed to determine the effective cryotherapy temperature for the inflammatory pain.
冷冻疗法治疗急性疼痛的生物学机制尚不清楚。此外，冷冻疗法的疗效是否取决于应用的温度也不清楚。本研究旨在阐明冷冻疗法的生物学效应，并研究不同温度下冷冻疗法在大鼠中的治疗效果。
这是一项使用大鼠膝关节关节炎模型的实验研究。35 只 Wistar 大鼠随机分为关节炎（AR）组、关节炎加 5°C 冷冻疗法（CR-5）组、关节炎加 10°C 冷冻疗法（CR-10）组和假关节炎对照组（CON）。通过向右侧膝关节注射高岭土/角叉菜胶混合物诱导关节炎。从注射后第 1 天开始，通过将右膝关节浸入 5°C 或 10°C 水中，每天进行 7 天的冷冻治疗。在 7 天内评估关节横径、压痛阈值和疼痛相关行为。通过免疫组织化学染色分析注射后 8 天膝关节中 CD68 阳性细胞的数量和脊髓背角中降钙素基因相关肽的表达。
与 AR 组相比，CR-5 和 CR-10 组在第 3 天横径、压痛阈值和疼痛相关行为均有改善。CR-5 和 CR-10 组的 CD68 阳性细胞数量和降钙素基因相关肽的表达均明显低于 AR 组。CR-5 和 CR-10 组之间所有结果均无显著差异。
冷冻疗法通过减少滑膜和中枢敏化来改善炎症性疼痛。此外，低于 10°C 的冷冻疗法效果独立于应用温度。
冷冻疗法可能有益于炎症急性期的疼痛和肿胀管理的物理治疗方法。需要进行翻译后的人类研究，以确定炎症性疼痛的有效冷冻治疗温度。
