Bone & Joint Research Group, Department of Medicine, University of Auckland.
Department of Orthopaedic Surgery, Middlemore Hospital, Auckland, New Zealand.
Rheumatology (Oxford). 2023 Mar 1;62(3):1343-1349. doi: 10.1093/rheumatology/keac392.
Basic calcium phosphate (BCP) crystals contribute to several syndromes associated with tendon disease, including acute calcific tendinitis and Milwaukee shoulder syndrome. Interactions between BCP crystals and tenocytes (tendon cells) may contribute to these clinical syndromes. This study aimed to determine the direct effects of BCP crystals on tenocyte function and viability.
In vitro assays were used to assess changes in human tenocytes cultured with BCP crystals. Real-time PCR was used to determine changes in the expression of tendon-related genes and extracellular matrix remodelling enzymes (MMPs; a disintegrin and metalloproteases, ADAMTS; and tissue inhibitor of metalloproteinases, TIMPs). ELISA was used to measure protein concentrations in tenocyte supernatants. MTT and alamarBlue™ assays were used to determine changes in cell viability.
BCP crystals upregulated tenocyte gene expression of MMP-1, MMP-3, ADAMTS-4 and TIMP-1 after 24 h. Time-course experiments showed expression peaked at 8 h for TIMP-1 and 48 h for MMP-1 and ADAMTS-4. Cyclooxygenase (COX)-1 gene expression was upregulated after 48 h. Tenocytes did not alter expression of scleraxis and tendon collagens, and expression of pro-inflammatory cytokines was not induced with BCP crystals. BCP crystals increased tenocyte release of prostaglandin E2 (PGE2) and MMP-1 protein after 24 h. However, neither COX-1 inhibition nor COX-2 inhibition led to consistent change in BCP crystal-induced tenocyte gene expression of extracellular matrix remodelling enzymes. BCP crystals had no effect on tenocyte viability.
BCP crystals induce extracellular matrix remodelling enzymes, but not inflammatory cytokines, in tenocytes.
磷酸钙（BCP）晶体与几种与肌腱疾病相关的综合征有关，包括急性钙化性肌腱炎和密尔沃基肩综合征。BCP 晶体与肌腱细胞（肌腱细胞）之间的相互作用可能导致这些临床综合征。本研究旨在确定 BCP 晶体对肌腱细胞功能和活力的直接影响。
体外分析用于评估与 BCP 晶体共培养的人肌腱细胞的变化。实时 PCR 用于确定与肌腱相关的基因和细胞外基质重塑酶（基质金属蛋白酶（MMP）；解整合素和金属蛋白酶，ADAMTS；和金属蛋白酶组织抑制剂，TIMP）的表达变化。ELISA 用于测量肌腱细胞上清液中的蛋白浓度。MTT 和 alamarBlue™测定用于确定细胞活力的变化。
BCP 晶体在 24 小时后上调了 MMP-1、MMP-3、ADAMTS-4 和 TIMP-1 的肌腱细胞基因表达。时程实验表明 TIMP-1 的表达在 8 小时达到峰值，而 MMP-1 和 ADAMTS-4 的表达在 48 小时达到峰值。COX-1 基因表达在 48 小时后上调。BCP 晶体未改变肌腱细胞中硬蛋白和肌腱胶原的表达，也未诱导细胞因子的表达。BCP 晶体增加了肌腱细胞在 24 小时后 PGE2 和 MMP-1 蛋白的释放。然而，COX-1 抑制或 COX-2 抑制均未导致 BCP 晶体诱导的细胞外基质重塑酶的基因表达发生一致变化。BCP 晶体对肌腱细胞活力没有影响。
BCP 晶体在肌腱细胞中诱导细胞外基质重塑酶，但不诱导炎症细胞因子。
