Hara Y, Ukai T, Yoshimura A, Shiku H, Kato I
Department of Periodontology, Nagasaki University School of Dentistry, 1-7-1 Sakamoto, Nagasaki 852, Japan.
Calcif Tissue Int. 1998 Jul;63(1):63-6. doi: 10.1007/s002239900490.
The purpose of this study was to clarify the involvement of CD4+ and CD8+ T cells on bone resorption induced by Escherichia coli endotoxin. Two kinds of monoclonal antibodies, anti-CD4 and/or anti-CD8, were employed for the depletion of each or both T cell subsets. E. coli endotoxin was injected into mouse mesial gingiva of the first molar of the left mandible every 48 hours for up to 14 days (7 injections). The mice were divided into four groups: CD4-depleted, CD8-depleted, T cell-depleted, and normal. The mice were sacrificed on the day after the 1st, 3rd, 4th, 5th, and 7th injection and alveolar bone was examined histopathologically and histomorphometrically. Bone surface in contact with osteoclasts was defined as the site of active resorption and the ratios of active resorption were compared among the four groups. In addition, sections obtained after the 1st, 4th, and 7th injection were immunohistologically stained in order to confirm the presence or absence of CD4+ or CD8+ T cells. Alveolar bone resorption gradually increased in normal mice as the number of injections increased. In contrast, alveolar bone resorption was significantly weaker in each or both subset-depleted mice. For the duration of the experimental period, the number of CD4+ T cells in CD8-depleted and normal mice significantly increased with increasing bone resorption. Considering the function of CD4+ and CD8+ T cells, these results suggest that each subset preferentially acts as a macrophage activator in the early period of bone resorption induced by E. coli endotoxin.
本研究的目的是阐明CD4+和CD8+ T细胞在大肠杆菌内毒素诱导的骨吸收中的作用。使用两种单克隆抗体，抗CD4和/或抗CD8，来耗尽每个或两个T细胞亚群。每48小时将大肠杆菌内毒素注射到左下颌第一磨牙的小鼠近中牙龈中，持续14天（共注射7次）。小鼠被分为四组：CD4耗尽组、CD8耗尽组、T细胞耗尽组和正常组。在第1、3、4、5和7次注射后的第二天处死小鼠，并对牙槽骨进行组织病理学和组织形态计量学检查。将与破骨细胞接触的骨表面定义为活跃吸收部位，并比较四组之间的活跃吸收比例。此外，对第1、4和7次注射后获得的切片进行免疫组织化学染色，以确认CD4+或CD8+ T细胞的存在与否。随着注射次数的增加，正常小鼠的牙槽骨吸收逐渐增加。相比之下，在每个或两个亚群耗尽的小鼠中，牙槽骨吸收明显较弱。在实验期间，CD8耗尽组和正常组中CD4+ T细胞的数量随着骨吸收的增加而显著增加。考虑到CD4+和CD8+ T细胞的功能，这些结果表明，在大肠杆菌内毒素诱导的骨吸收早期，每个亚群优先作为巨噬细胞激活剂发挥作用。
