Possible Role of Gingival Epithelial Cells in Host Defense Mechanism of Periodontal Disease Progression

本研究旨在检测分泌性白细胞蛋白酶抑制剂（SLPI）和IL-1受体拮抗剂（IL-1ra）在牙龈上皮细胞中的表达，并探讨龈沟液（GCF）中SLPI与牙周临床参数的可能关系。免疫细胞化学方法在冷冻切片的牙龈上皮上检测到SLPI，并在培养的健康牙龈角质形成细胞的表面和内部表达。测定15例成人牙周炎患者GCF中SLPI、α1蛋白酶抑制剂（α1-PI）水平及中性粒细胞弹性酶（NE）活性，并检测牙周临床参数。在30个检测部位中，牙周炎部位的样品中SLPI、α1-PI、NE和GCF的含量均明显高于健康部位的样品。SLPI、α1-PI和NE与探测深度相关。NE和α1- pi与临床依恋丧失显著相关。提示SLPI和α1- pi可能与牙周炎部位的炎症有关。为了明确人牙龈角质形成细胞中IL-1和IL-1ra的表达，我们采用酶联免疫吸附法和逆转录聚合酶链反应（RT-PCR）研究了人牙龈角质形成细胞中IL-1α和IL-1ra的蛋白表达和mRNA表达。此外，我们用免疫组织化学方法研究了il -1α和IL-1ra在健康和炎症牙龈上皮中的存在。在TNF-α刺激下，细胞相关IL-1α水平显著升高，而条件培养基中IL-1α水平和IL-1ra蛋白水平不受TNF-α的影响。在TNF-α刺激下，细胞内IL-1α和IL-1ra mRNA转录增强。此外，免疫组化发现牙龈上皮中存在IL-1ra，而不存在IL-1α。这些结果表明，人牙龈角质形成细胞表达il -1α和IL-1ra，可能参与了il -1α和IL-1ra对牙周病炎症的调节。少

The purpose of the present research project was to detect the expression of secretory leukocyte protease inhibitor (SLPI) and IL-1 receptor antagonist (IL-1ra) in gingival epithelial cells and to clarify the possible relationship between SLPI in gingival crevicular fluid (GCF) and the periodontal clinical parameters.SLPI was immunocytochemically detected on frozen-sectioned gingival epithelium and expressed on the surface and inside of cultured gingival keratinocytes from healthy gingiva. The levels of SLPI and α1-protease inhibitor (α1-PI) and neutrophil elastase (NE) activity in GCF were measured and periodontal clinical parameters were examined in fifteen adult periodontitis patients. In thirty examined sites, significantly higher amounts of SLPI, α1-PI, NE and GCF were consistently obtained in samples from periodontitis sites than in samples from healthy sites. SLPI, α1-PI and NE were found to correlate with probing depth. NE andα1-PI were significantly correlated with increasing c … More linical attachment loss. These results suggested that SLPI andα1-PI may be related to the inflammation in periodontitis sites.To clarify the expression of IL-1 and IL-1ra in human gingival keratinocytes, we studied the protein production and mRNA expression of IL-1α and IL-1ra in human cultured gingival keratinocytes using enzyme-linked immunosorbent assay and reverse transcription polymerase chain reaction (RT-PCR). Furthermore, we studied immunohistochemically the presence of IL-1αand IL-1ra in the epithelium of healthy and inflamed gingiva. The level of cell-associated IL-1α was significantly increased under stimulation of TNF-α, while the level of IL- 1α in conditioned medium and the levels of IL-1ra protein were not influenced by TNF-α. IL-1α and intracellular IL-1ra mRNA transcripts were enhanced under stimulation with TNF-αby RT-PCR. Furthermore, the presence of IL-1ra, but not IL-1α, found by immunohistochemistry in the epithelium of gingiva. These results indicated that human gingival keratinocytes expressed IL-1αand IL-1ra, and may be involved in the regulation of inflammation of periodontal disease by IL-1αand IL-1ra. Less