目的: 观察比格犬相对健康的牙周组织和实验性牙周炎的牙周组织标本中钙结合蛋白的表达分布和细胞定位,探讨其与牙周炎症的关系和可能发挥的作用。方法: 结扎法诱导建立比格犬下颌第二磨牙实验性牙周炎模型,对侧同名牙作为健康对照,诱导12周后处死,组织脱矿后常规制作连续切片,免疫组织化学法检测钙结合蛋白在比格犬健康和实验性牙周炎的组织标本中的表达和分布,明确细胞定位;免疫细胞化学法检测体外培养的原代人牙周组织细胞中钙结合蛋白的表达。结果: 在健康牙龈组织中,钙结合蛋白表达于牙龈上皮、中性粒细胞,且在结合上皮处呈强阳性表达;牙周炎症病损中,牙龈上皮细胞钙结合蛋白表达水平上调,存在强表达钙结合蛋白的中性粒细胞大量浸润,成纤维样细胞(牙龈结缔组织、牙周膜组织)、骨髓成纤维细胞、微血管内皮细胞存在钙结合蛋白的诱导表达;在体外培养的人牙周膜细胞、人牙龈成纤维细胞中均检测到钙结合蛋白的表达。结论: 钙结合蛋白组成性表达于牙龈上皮细胞、中性粒细胞,可能对维持牙周组织内环境稳定和完整性发挥重要作用。牙周炎症诱导牙龈成纤维细胞、牙周膜细胞、骨髓成纤维细胞和血管内皮细胞表达的钙结合蛋白可能在抗微生物感染、促炎症细胞迁移等方面发挥作用。

Objective: Calprotectin, the heterdimer of S100A8 and S100A9, is the major cytoplasmic protein of neutrophils, which is also expressed or induced in gingival epithelial cells, activated mononuclear macrophages and vascular endothelial cells. Calprotectin is intimately associated with the initiation and progression of periodontitis, but the in vivo expression patterns of calprotectin in healthy and inflamed periodontal tissue are not fully understood. To observe the expression, distribution and cellular localization of calprotectin in the samples of healthy periodontal tissues and experimental periodontitis tissues of Beagles and to explore their relationship with periodontal inflammation and possible effect. Methods: Experimental periodontitis model was established by ligation around the mandibular second molar of the Beagle dogs, while the contralateral teeth were healthy controls. Induction duration was 12 weeks, before the dogs were executed. Tissue specimens were demineralized and serial sections were made conventionally. The in vivo expression of calprotectin in the healthy and inflamed periodontal tissues were examined by immunohistochemistry. The in vitro expression of calprotectin in human primary gingival fibroblasts (GFs) and periodontal ligament (PDL) cells were detected by immunocytochemistry. Results: Immunohistochemistry analysis indicated that calprotectin was expressed in gingival epithelial cells and infiltrated neutrophils in the healthy periodontium within the gingival epithelium, S100A8/A9 was most strongly expressed in the junctional epithelium, followed by surface epithelium, and least expressed in the sulcular epithelium. The S100A8/A9 expression levels were sharply defined at the junction between the junctional epithelium and the sulcular epithelium. In periodontal inflammatory lesions, the expression level of calprotectin in sulcular epithelium and junctional epithelium was up-regulated than that in the healthy gingival epithelium. Calprotectin was inducibly expressed in fibroblast-like cells in gingival connective tissue and periodontal ligament tissue, microvascular endothelial cells (ECs) and bone marrow fibroblasts under inflammatory conditions. Additionally, the expression of calprotectin in primary human GFs and PDL cells was confirmed by immunnocytochemistry staining. Conclusion: Constitutively expressed in neutrophils and gingival epithelial cells, and calprotectin might maintain the homeostasis and integrity of periodontium. Inflammation-induced expression of calprotectin in GFs, PDL cells, microvascular ECs and bone marrow fibroblasts might process anti-microbial function and promote leukocytes transmigration to defend the host against the microorganisms.