OBJECTIVE The present study aimed to investigate whether experimentally induced lumbar facet-joint OA lead to degenerative changes and enhanced SP expression within the ipsilateral neurosegmentally linked tibiofemoral cartilage. METHODS Adult male Sprague-Dawley rats were assigned to left side L5-L6 facet mechanical compression injury (surgery) ( n = 6), L5-L6 facet exposure with no compression (sham) ( n = 5), or naïve (no surgery) ( n = 4) groups. The morphology of the tibiofemoral articular cartilage was assessed using a modified Mankin scoring system. Immunohistochemistry was used to examine the density of chondrocytes stained positive for SP (cells/cm2) in the ipsilateral tibiofemoral cartilage at 28 days postintervention. RESULTS Tibiofemoral cartilage in the surgery group showed consistent loss of superficial zone chondrocytes, mild roughening of the articular surface and occasional chondrocyte clusters as well as a greater density of SP mainly in the superficial cartilage zone compared with sham and naïve groups, although they also had a basic SP-expression. CONCLUSION Our results support the hypothesis that neurogenic mechanisms may mediate the spread of SP to neurosegmentally linked heterologous joints affecting the distal cartilage homeostasis. These findings contribute additional insight into the potential role of neurogenic inflammation with implications in the pathophysiology of chronic inflammatory joint disease and OA.

中文翻译：

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暴露于腰椎损伤的大鼠同侧膝关节软骨中P物质的免疫反应性增加。

目的本研究旨在探讨实验性诱导的腰椎小关节关节炎OA是否导致同侧神经节段性胫股关节软骨内的退行性改变和增强的SP表达。方法将成年雄性Sprague-Dawley大鼠分为左侧L5-L6小平面机械性压迫性损伤（手术）（n = 6），L5-L6小平面暴露，无压迫（假手术）（n = 5）或幼稚（不进行手术） ）（n = 4）组。使用改良的Mankin评分系统评估胫股关节软骨的形态。免疫组化用于检查干预后28天同侧胫股软骨中SP染色阳性的软骨细胞密度（细胞/ cm2）。结果手术组胫股软骨表现出一致的表层软骨细胞丢失，尽管与假手术组和幼稚组相比，尽管它们也具有基本的SP表达，但关节表面的轻度粗糙和偶发的软骨细胞簇以及主要在浅软骨区的SP密度更高。结论我们的结果支持以下假说，即神经发生机制可能介导SP扩散至影响远端软骨稳态的神经节链接异源关节。这些发现为神经源性炎症的潜在作用提供了进一步的见解，对慢性炎症性关节疾病和OA的病理生理有影响。结论我们的结果支持以下假说，即神经发生机制可能介导SP扩散至影响远端软骨稳态的神经节链接异源关节。这些发现为神经源性炎症的潜在作用提供了进一步的见解，对慢性炎症性关节疾病和OA的病理生理有影响。结论我们的结果支持以下假说，即神经发生机制可能介导SP扩散到影响远端软骨动态平衡的神经节链接异源关节。这些发现为神经源性炎症的潜在作用提供了更多的见解，对慢性炎症性关节疾病和OA的病理生理有影响。