Effects of sex hormones and aging on regeneration of periodontal tissue

牙周病治疗的主要目标是矿化组织和软结缔组织的再生。PDL细胞在体外产生矿化结节是PDL细胞再生治疗的重要功能之一。本研究旨在探讨雌二醇对人PDL细胞矿化结节形成的影响。PDL细胞从健康供体中获得，并在含有10%胎牛血清的DMEM中保存。检测雌二醇的作用时采用无血清培养基。用分光光度法分析超声破坏细胞上清中ALP活性。用茜素红染色PDL细胞并计数结节数，观察矿化结节的形成情况。与对照组相比，雌二醇20 ng/ml显著提高了ALP活性和矿化结节形成。这些结果提示雌激素水平可能改变牙周组织的再生活性。已知牙周韧带（PDL）细胞具有成骨细胞样特征，并且能够分化为成骨细胞。由于人成骨细胞表达雌激素受体mRNA，因此PDL细胞也可能表达这些受体。然而，关于雌激素受体mRNA在PDL细胞中的存在，报道了相互矛盾的发现。为了确定PDL细胞是否表达雌激素受体mRNA，使用两种不同的引物进行逆转录聚合酶链反应（RT-PCR）。从正畸拔牙的健康前磨牙牙周韧带中获得牙周韧带细胞。以人乳腺腺癌细胞系MCF7为阳性对照。使用一种与MCF7相比强度较小的引物检测PDL细胞中雌激素受体mRNA的表达。南方杂交证实了这些结果。我们的研究结果表明，PDL细胞低水平表达雌激素受体mRNA。

A primary objective in the treatment of periodontal disease is the regeneration of the mineralizec and soft connective tissue. PDL cells produce mineralized nodules in vitro which is one of the important functions of PDL cells for regenerative therapy. The purpose of this study was to investigate the effects of estradiol on mineralized nodule formation by human PDL cells. PDL cells were ob-tained from healthy donors and maintained in DMEM with 10% fetal bovine serum. Serum-free medium was used when the effects of estradiol were tested. ALP activity in the supernatant of cells disrupted by sonication was analyzed spectrophotometrically. The formation of mineralized nodules was assessed by staining the PDL cells with alizarine red and counting the number of nodules. at Estradiol 20 ng/ml significantly enhanced the ALP activity and mineralized nodule formation compared to the control. These results suggested that estrogen status may modify the regenerative activity of periodontal tissue.Periodontal ligament (PDL) cells are known to have osteoblast-like features and are capable of differentiating into osteogenic cells. As human osteoblasts express estrogen receptor mRNA, it is possible that PDL cells also express these receptors. However, conflicting findings have been reported regarding the presence of oestrogen receptor mRNA in PDL cells. To determine whethe PDL cells express oestrogen receptor mRNA, reverse transcriptase-polymerase chain reaction (RT-PCR) was performed using two different primers. Periodontal ligament (PDL) cells were obtained from a healthy periodontal ligament of premolar extracted for orthodontic reasons. The humar breast adenocarcinoma cell line MCF7 was used as a positive control. Expression of oestrogen receptor mRNA in PDL cells was detected using one of the primers with less intensity compared to MCF7. Southern hybridization confirmed these results. Our findings suggest that PDL cells express oestrogen receptor mRNA at low levels.