Discharge of collagenase from a gingival fibroblast infected with oral mycoplasma

培养在平板中的人正常牙龈成纤维细胞(Gin-1)，无论作用于唾液支原体(MS)或口腔支原体(Mo)的菌体细胞，还是暴露于MS或牙龈卟啉单胞菌(PG)细胞的细胞膜中，随着时间的推移，Gin-1细胞的形态均呈椭圆形。这种形态变化是由膜上的活细胞引起的。后者作用96h后，Gin-1细胞进一步脱离平板，形态改变和脱落可能是由细胞外分泌的胶原酶引起的，但在培养上清液中没有发现胶原酶活性。还有一种可能是细胞形态的改变和脱落是由产生的细胞因子引起的，因此，我们用酶联免疫测定方法研究了培养上清液中炎性细胞因子(IL-1β、IL-6和TNFα)的产生。所有病例均检测到较高的IL-6含量。肿瘤坏死因子α和IL-1β也被检测到对PG刺激，但不对ms和Mo刺激。IL-6最初被认为是刺激B细胞产生免疫球蛋白的因子，并被讨论参与炎症，如关节炎。在牙科领域，IL-6被发现存在于牙周病的病变中，并被认为与牙周病的病因有关。因此，本研究发现口腔支原体可诱导牙周成纤维细胞分泌IL-6，提示其在牙周病中起重要的病因学作用。

Human normal gingival fibroblast (Gin-1) cells cultured in a plate showed a morphological change to spheroid with time when they were exposed to either vialbe cells of Mycoplasma salivarium (Ms) or Mycoplasma orale (Mo) or cell membranes of Ms or Porphyromonas gingivalis (Pg) cells fractured by sonication. This morphological change was most strongly induced by viable cells of Mo and Ms membranes. The latter further caused, after 96 h-exposure, detachment of Gin-1 cells from the plate.The morphological change and the detachment were supposed to be caused by collagenase discharged from the cells, but no collagenase activity was found in the culture medium. There is another possibility that the morphological change and the detachment are attributed to cytokines produced and, hence, the production of inflammatory cytokines (IL-1beta, IL-6 and TNFalpha) in the culture medium was investigated by using an enzyme-linked immunosorvent assay. High contents of IL-6 were detected for all cases. TNFalpha and IL-1beta were also detected for Pg stimulation but not for Ms and Mo stimulations.IL-6 was originally identified as a factor which stimulates immunoglobulin production by B cells and is discussed to be involved in inflammation such as arthritis. In the field of dental science, IL-6 was found in the lesion of periodontal disease and is discussed to be involved in its etiology. Therefore, the present finding that oral mycoplasmas induce IL-6 secretion from a gingival fibroblast suggests that they play an important etiological role in periodontal diesease.