Osteoarthritis is a mechanical abnormality characterized by chronic joint pain associated with degeneration of the articular cartilage, synovitis, and local inflammation, leading to loss of function and pain. A connection exists between the peripheral nervous system and inflammatory joint degeneration. The process by which inflammation is influenced by the nervous system is known as neuroinflammation. One of the neuropeptides involved in peripheral neuroinflammation is nociceptin, a peptide related to the opioid class of substances. Nociceptin has both pro- and anti-inflammatory effects. Some studies show that nociceptin can be measured in synovial fluid, while other studies have not been able to detect it. The presence of nociceptin in synovial fluid could imply a molecular role for the neuropeptide in the joint, both physiologically as well as pathophysiologically. The goal of this pilot study was to determine whether nociceptin was present in the synovial fluid of osteoarthritic knees. Patients undergoing primary total knee arthroplasty were enrolled after Institutional Review Board approval was obtained. Synovial fluid was aspirated from patients’ operative knee joints and blood samples were obtained. A commercially available enzyme Immunoassay kit was used to test for nociceptin. A linear mixed-effects model was developed to account for the repeated measurements and baseline covariates. Least squares (adjusted) means were derived from the model to compare the sample types and to compare subgroups. Twenty patients were included in this study. Nociceptin was detected in the synovial fluid and plasma of all patients. The mean concentration (± standard deviation) of nociceptin in synovial fluid was 28.7 ± 18.2 pg/ml. The mean concentration of nociceptin in plasma was 45.2 ± 24.3 pg/ml pre-procedure, and 40.1 ± 20.6 pg/ml post-tourniquet deflation. The nociceptin concentration in synovial fluid was significantly lower than the nociceptin concentration in plasma, both pre-procedure and post-tourniquet deflation (p = 0.002 and p = 0.016 respectively). The nociceptin concentration in both plasma and synovial fluid was significantly lower in females versus males (p = 0.012). We demonstrated that nociceptin is present in synovial fluid and plasma of patients undergoing total knee arthroplasty. This implies a potential role for nociceptin in modulating inflammation in osteoarthritis. ClinicalTrials.gov , NCT02528916 . Retrospectively registered on August 19, 2015,

中文翻译：

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接受全膝关节置换术的患者的滑液中存在伤害感受肽。


骨关节炎是一种机械异常，其特征是与关节软骨退化、滑膜炎和局部炎症相关的慢性关节疼痛，导致功能丧失和疼痛。周围神经系统和炎症性关节变性之间存在联系。炎症受神经系统影响的过程称为神经炎症。参与周围神经炎症的神经肽之一是伤害感受肽，一种与阿片类物质相关的肽。伤害感受肽具有促炎和抗炎作用。一些研究表明，可以在滑液中检测到伤害感受素，而其他研究则无法检测到它。滑液中伤害感受肽的存在可能意味着神经肽在关节中的分子作用，无论是生理学还是病理生理学。这项初步研究的目的是确定骨关节炎膝盖的滑液中是否存在伤害感受肽。在获得机构审查委员会批准后，接受初次全膝关节置换术的患者被纳入。从患者的手术膝关节中吸出滑液并获取血样。使用市售的酶免疫测定试剂盒来测试伤害感受肽。开发了线性混合效应模型来解释重复测量和基线协变量。从模型中得出最小二乘（调整后）平均值，以比较样本类型并比较子组。本研究纳入了 20 名患者。所有患者的滑液和血浆中均检测到伤害感受肽。滑液中伤害感受素的平均浓度（±标准差）为 28.7 ± 18.2 pg/ml。 术前血浆中伤害感受素的平均浓度为 45.2 ± 24.3 pg/ml，止血带放气后为 40.1 ± 20.6 pg/ml。手术前和止血带放气后，滑液中的伤害感受肽浓度均显着低于血浆中的伤害感受肽浓度（分别为 p = 0.002 和 p = 0.016）。女性血浆和滑液中的伤害感受素浓度显着低于男性 (p = 0.012)。我们证明了痛敏肽存在于接受全膝关节置换术的患者的滑液和血浆中。这意味着伤害感受肽在调节骨关节炎炎症方面具有潜在作用。临床试验.gov，NCT02528916。追溯注册日期为2015年8月19日，