Cozin Matthew, Pinker Bradley M, Solemani Kimberley, Zuniga Jeremy M, Dadaian Stephen C, Cremers Serge, Landesberg Regina, Raghavan Srikala
College of Dental Medicine, Columbia University, New York, NY 10032, USA.
J Oral Maxillofac Surg. 2011 Oct;69(10):2564-78. doi: 10.1016/j.joms.2011.03.005. Epub 2011 Jul 31.
Osteonecrosis of the jaws (ONJ) is a clinical condition that is characterized by a nonhealing breach in the oral mucosa resulting in exposure of bone and has been increasingly reported in patients receiving bisphosphonate (BP) therapy. Although the pathogenesis and natural history of ONJ remain ill-defined, it appears that the oral soft tissues play a critical role in the development of this condition. We examined the effects of the nitrogen-containing BPs pamidronate and zoledronate on primary human gingival fibroblasts.
Primary gingival fibroblasts were exposed to clinically relevant doses of pamidronate and zoledronate. Cellular proliferation was measured with an MTS/PMS reagent-based kit (Promega, Madison, WI), scratch wound assays were performed to measure cellular migration, and apoptosis was measured by use of terminal deoxynucleotidyl transferase-mediated dUTP-FITC end labeling and caspase assays. The BP-exposed cells were treated with 10-ng/mL recombinant human platelet-derived growth factor BB (rhPDGF-BB) and 50-μmol/L geranylgeraniol (GGOH).
Gingival fibroblasts are significantly more sensitive to inhibition of proliferation by zoledronate compared with pamidronate. Exposure of these cells to pamidronate but not zoledronate resulted in an increase in cellular apoptosis. Furthermore, exposure of gingival fibroblasts to pamidronate or zoledronate resulted in a decrease in cellular migration. We show that these defects are due to a loss of cell-substratum adhesion and a reduction of F-actin bundles. Finally, we show that the addition of rhPDGF-BB and GGOH in vitro is able to partially rescue the cell proliferation, migration, and adhesion defects.
The cytotoxic effects of BPs on oral fibroblasts and their significant reversal by the addition of GGOH and rhPDGF-BB provide both the potential mechanism and treatment options for ONJ.
颌骨骨坏死（ONJ）是一种临床病症，其特征为口腔黏膜出现不愈合的创口，导致骨暴露，且接受双膦酸盐（BP）治疗的患者中该病症的报告日益增多。尽管ONJ的发病机制和自然病程仍不明确，但口腔软组织似乎在该病症的发展中起关键作用。我们研究了含氮双膦酸盐帕米膦酸盐和唑来膦酸盐对原代人牙龈成纤维细胞的影响。
将原代牙龈成纤维细胞暴露于临床相关剂量的帕米膦酸盐和唑来膦酸盐。使用基于MTS/PMS试剂的试剂盒（Promega，麦迪逊，威斯康星州）测量细胞增殖，进行划痕伤口试验以测量细胞迁移，并通过末端脱氧核苷酸转移酶介导的dUTP-FITC末端标记和半胱天冬酶试验测量细胞凋亡。用10 ng/mL重组人血小板衍生生长因子BB（rhPDGF-BB）和50 μmol/L香叶基香叶醇（GGOH）处理暴露于BP的细胞。
与帕米膦酸盐相比，牙龈成纤维细胞对唑来膦酸盐抑制增殖的敏感性明显更高。这些细胞暴露于帕米膦酸盐而非唑来膦酸盐会导致细胞凋亡增加。此外，牙龈成纤维细胞暴露于帕米膦酸盐或唑来膦酸盐会导致细胞迁移减少。我们表明这些缺陷是由于细胞与基质的粘附丧失和F-肌动蛋白束减少所致。最后，我们表明在体外添加rhPDGF-BB和GGOH能够部分挽救细胞增殖、迁移和粘附缺陷。
双膦酸盐对口腔成纤维细胞的细胞毒性作用以及添加GGOH和rhPDGF-BB对其的显著逆转，为ONJ提供了潜在的发病机制和治疗选择。
