Kawanabe Noriaki, Murakami Kaoru, Takano-Yamamoto Teruko
Department of Orthodontics and Dentofacial Orthopedics, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-cho, Okayama 700-8525, Japan.
Biochem Biophys Res Commun. 2006 Jun 16;344(4):1278-83. doi: 10.1016/j.bbrc.2006.03.237. Epub 2006 Apr 21.
Periodontal ligament (PDL) is capable of regenerating several types of periodontal tissues. However, the stem cells in PDL have been less well characterized. Recently, it has been represented that stem cells have a potent ability to exclude Hoechst dye, and cells possessing this phenotype are termed "side population (SP)." In addition, it is suggested that the SP cells are ubiquitously present in adult tissues, therefore, we investigated the presence of SP cells in PDL. Hoechst dye efflux assay showed that PDL cells include 3.9% SP cells. This SP profile disappeared in the presence of verapamil or reserpine. Only ABCG2-expressing cells were detected in PDL cells by flow cytometric analysis. Furthermore, RT-PCR demonstrated that ABCG2 mRNA expression remarkably correlated with PDL SP phenotype. Our findings demonstrate that PDL contains ABCG2-dependent SP cells. Hence, it is possible that this population could contribute to periodontal tissue regeneration as PDL stem cells.
牙周韧带（PDL）能够再生多种类型的牙周组织。然而，牙周韧带中的干细胞尚未得到充分表征。最近，有研究表明干细胞具有强大的排除Hoechst染料的能力，具有这种表型的细胞被称为“侧群（SP）”细胞。此外，有研究表明SP细胞普遍存在于成体组织中，因此，我们研究了牙周韧带中SP细胞的存在情况。Hoechst染料外排试验表明，牙周韧带细胞中含有3.9%的SP细胞。在维拉帕米或利血平存在的情况下，这种SP细胞特征消失。通过流式细胞术分析在牙周韧带细胞中仅检测到表达ABCG2的细胞。此外，逆转录-聚合酶链反应（RT-PCR）表明ABCG2 mRNA表达与牙周韧带SP细胞表型显著相关。我们的研究结果表明牙周韧带含有ABCG2依赖的SP细胞。因此，这群细胞有可能作为牙周韧带干细胞促进牙周组织再生。
