Molecular-Genetic Mechs Underlying Effects of Anti-inflammatory/Analgesic Drugs

组织损伤启动了一系列促炎介质和痛觉过敏物质，包括胰高血糖素、细胞因子和趋化因子。细胞因子和趋化因子的相互作用及其信号通路的激活有助于炎症和炎性疼痛的发展。炎症还受肾上腺素、缓激肽、一氧化氮（NO）和细胞粘附分子的合成和释放调节，所述细胞粘附分子也激活有助于炎症和炎性疼痛发展的途径。几十年来，非甾体抗炎药（NSAID）一直是治疗炎性疾病和炎性疼痛的主要药物，但对环氧合酶（考克斯）的诱导形式的认识为开发选择性考克斯-2抑制剂以避免传统NSAID抑制考克斯-1的不良胃肠道作用提供了理论基础。然而，越来越多的证据表明，该模型过于简化，无法解释在临床和实验研究中观察到的传统NSAID和考克斯-2抑制剂的治疗和不良反应的差异。对促炎介质和抗炎/镇痛药物的生物学特性的新见解表明，它们具有比它们在改善炎性疼痛中的作用更独立的作用。 我们最近使用组织损伤的临床模型进行的一系列研究表明，细胞因子/趋化因子的外周表达谱在炎症发展的早期和晚期时间点受到不同的调节。非甾体抗炎药和选择性考克斯-2抑制剂对它们的基因表达和途径表现出不同的调节作用。使用微阵列和qRT-PCR基因表达分析，我们评估了细胞因子/趋化因子的基因表达谱的变化及其与患者报告的疼痛强度的相关性，组织损伤后，在急性炎症性疼痛的良好表征模型。术后疼痛强度逐渐增加，局部麻醉抵消。在炎症和炎性疼痛的早期阶段，组织损伤导致IL-6、IL-8、CCL 2、TNF-α、CXCL 1、CXCL 2的基因表达显著上调。IL-6基因表达上调与IL-8、CCL 2、CXCL 1和CXCL 2基因表达上调显著相关。有趣的是，组织损伤诱导的IL-6、IL-8和CCL 2基因表达的上调与急性炎性疼痛发作的早期时间点的疼痛强度呈正相关。我们进一步发现，在这个早期的时间点，激肽B1受体在转录水平上响应于激肽激活而上调，并且通过TRPV 1受体的激活与IL 6、IL 8和CCL 2的产生相关。我们的一个有趣的发现是，磷酸二酯酶4型（PDE 4D）的表达在组织损伤后的早期时间点显著增加。选择性和非选择性COX抑制剂降低了PDE 4D的上调，这可能表明了NSAID镇痛和抗炎作用的新机制。然而，在炎症和炎性疼痛发展的后期，我们发现组织损伤诱导的IL 8上调与基质金属蛋白酶（MMP）通路包括MMP-1、MMP-3和PLAT的上调显著相关，这可能代表了一种新的治疗目标，在管理慢性炎症性疼痛的临床实践中，MMP途径已涉及调节神经血管通透性和脱髓鞘。 近年来的研究强调了炎性细胞因子和趋化因子在周围神经病理性疼痛发生发展中的重要作用。炎性细胞浸润和随后的细胞因子、趋化因子、肾上腺素、缓激肽和一氧化氮的分泌在创伤、糖尿病和化疗引起的周围神经病变的疼痛/痛觉过敏机制中起关键作用。我们的这些发现在基因表达水平上为人类急性炎症性疼痛的新途径提供了证据，这可能有助于确定慢性疼痛患者的干预靶点。未来的发展方向将集中在癌症治疗并发症的症状生物学，如化疗引起的周围神经性疼痛和评估磷酸二酯酶和MMP抑制剂作为潜在的新的治疗和神经保护策略。

Tissue injury initiates a cascade of proinflammatory mediators and hyperalgesic substances including prostaglandins, cytokines and chemokines. Interactions of cytokine and chemokine and activation of their signaling pathways contribute to the development of inflammation and inflammatory pain. Inflammation is also regulated by the synthesis and release of prostaglandins, bradykinin, nitric oxide (NO) and cell adhesion molecules that also activate pathways that contribute to the development of inflammation and inflammatory pain. For decades, non-steroidal anti-inflammatory drugs (NSAIDs) have been the mainstay of treatment for inflammatory disorders and inflammatory pain but the recognition of an inducible form of cyclooxygenase (COX) provided a rationale for developing selective COX-2 inhibitors to avoid the adverse gastrointestinal effects of COX-1 suppression by traditional NSAIDs. However, increasing evidence indicates that this model is too oversimplified to explain the observed differences in therapeutic and adverse effects of traditional NSAIDs and COX-2 inhibitors in clinical and experimental studies. New insights into the biological properties of proinflammatory mediators and anti-inflammatory/analgesic drugs suggest that they have more independent effects than their role in the amelioration of inflammatory pain. Our recent series of studies using a clinical model of tissue injury demonstrate that peripheral expression profiles of cytokines/chemokines are differently regulated at early and later time points in the development of inflammation. NSAIDs and selective COX-2 inhibitors show different regulatory effects on their gene expression and pathways. Using microarray and qRT-PCR gene expression analyses, we evaluated changes in gene expression profiles of cytokines/chemokines and their correlation with patient-reported pain intensity following tissue injury in a well characterized model of acute inflammatory pain. Pain intensity gradually increased postoperatively with local anesthetic offset. At the early phase of inflammation and inflammatory pain, tissue injury resulted in a significant up-regulation in the gene expression of IL-6, IL-8, CCL2, TNF-, CXCL1, CXCL2. The up-regulation of IL-6 gene expression was significantly correlated to the up-regulation of the gene expression of IL-8, CCL2, CXCL1 and CXCL2. Interestingly, the tissue injury-induced up-regulation of IL-6, IL-8 and CCL2 gene expression was positively correlated to pain intensity at this early time point, the onset of acute inflammatory pain. We further found that at this early time point, the kinin B1 receptor was up-regulated at the transcriptional level in response to kinin activation and was associated with the production of IL6, IL8 and CCL2 via the activation of TRPV1 receptors. One of our interesting findings is that the expression of phosphodiestrase type 4 (PDE4D) was significantly increased at this early time point following tissue injury. Selective and non-selective COX-inhibitors reduced the up-regulation of PDE4D, which may indicate a novel mechanism contributing to NSAIDs analgesic and anti-inflammatory effects. However, in the later phase of the development of inflammation and inflammatory pain, we found that tissue injury-induced up-regulation of IL8 was significantly correlated with the up-regulation of matrix metalloproteinase (MMP) pathways including MMP-1, MMP-3 and PLAT, which might represent a novel therapeutic target in the management of chronic inflammatory pain in clinical practice as MMP pathways have been implicated in regulating neurovascular permeability and demyelination in patients with symptomatic neuropathy. Recent studies have emphasized the important contribution of the inflammatory cytokines and chemokines to the development of peripheral neuropathic pain. Inflammatory cell infiltration and subsequent secretion of cytokines, chemokines, prostaglandins, bradykinin and nitric oxide play pivotal roles in the pain/hyperalgesia mechanisms of peripheral neuropathy caused by trauma, diabetes and chemotherapy. Our these findings provide evidence at the gene expression level of novel pathways involved in acute inflammatory pain in human that may help to identify the targets for intervention in patients with chronic pain. Future directions will focus on the symptoms biology of cancer treatment complications such as chemotherapy-induced peripheral neuropathic pain and evaluation of phophodiesterase and MMP inhibitors as potential novel therapeutic and neuroprotective strategies.