Fitzsimmons Robert J, Gordon Stephen L, Kronberg James, Ganey Timothy, Pilla Arthur A
The Technical Basis LLC, 24769 Redlands Blvd, Suite E, Loma Linda, California 92354, USA.
J Orthop Res. 2008 Jun;26(6):854-9. doi: 10.1002/jor.20590.
A potential treatment modality for joint pain due to cartilage degradation is electromagnetic fields (EMF) that can be delivered, noninvasively, to chondrocytes buried within cartilage. A pulsed EMF in clinical use for recalcitrant bone fracture healing has been modified to be delivered as a pulsed electric field (PEF) through capacitive coupling. It was the objective of this study to determine whether the PEF signal could have a direct effect on chondrocytes in vitro. This study shows that a 30-min PEF treatment can increase DNA content of chondrocyte monolayer by approximately 150% at 72 h poststimulus. Studies intended to explore the biological mechanism showed this PEF signal increased nitric oxide measured in culture medium and cGMP measured in cell extract within the 30-min exposure period. Increasing calcium in the culture media or adding the calcium ionophore A23187, without PEF treatment, also significantly increased short-term nitric oxide production. The inhibitor W7, which blocks calcium/calmodulin, prevented the PEF-stimulated increase in both nitric oxide and cGMP. The inhibitor L-NAME, which blocks nitric oxide synthase, prevented the PEF-stimulated increase in nitric oxide, cGMP, and DNA content. An inhibitor of guanylate cyclase (LY83583) blocked the PEF-stimulated increase in cGMP and DNA content. A nitric oxide donor, when present for only 30 min, increased DNA content 72 h later. Taken together, these results suggest the transduction pathway for PEF-stimulated chondrocyte proliferation involves nitric oxide and the production of nitric oxide may be the result of a cascade that involves calcium, calmodulin, and cGMP production.
因软骨降解导致的关节疼痛的一种潜在治疗方式是电磁场（EMF），它可以无创地作用于埋在软骨内的软骨细胞。临床上用于顽固性骨折愈合的脉冲电磁场已被改良为通过电容耦合以脉冲电场（PEF）的形式传递。本研究的目的是确定PEF信号是否能在体外对软骨细胞产生直接影响。这项研究表明，30分钟的PEF处理可使刺激后72小时软骨细胞单层的DNA含量增加约150%。旨在探索其生物学机制的研究表明，在30分钟的暴露期内，该PEF信号可增加培养基中测量的一氧化氮和细胞提取物中测量的环磷酸鸟苷（cGMP）。在未进行PEF处理的情况下，增加培养基中的钙或添加钙离子载体A23187，也能显著增加短期内一氧化氮的产生。阻断钙/钙调蛋白的抑制剂W7可阻止PEF刺激的一氧化氮和cGMP的增加。阻断一氧化氮合酶的抑制剂L-NAME可阻止PEF刺激的一氧化氮、cGMP和DNA含量的增加。鸟苷酸环化酶抑制剂（LY83583）可阻断PEF刺激的cGMP和DNA含量的增加。一种一氧化氮供体仅存在30分钟，72小时后可增加DNA含量。综上所述，这些结果表明，PEF刺激软骨细胞增殖的转导途径涉及一氧化氮，一氧化氮的产生可能是一个涉及钙、钙调蛋白和cGMP产生的级联反应的结果。
