Expression of IL-1 and adhesion molecules during osteoclast development in rat periapical lesions

为探讨根尖周炎时骨质破坏的病理生物学机制，采用免疫组织化学方法检测了白细胞介素-1（IL-1）与细胞间粘附分子-1（ICAM-1）和白细胞功能相关抗原-1（LFA-1）在大鼠根尖周病变中表达的关系。在急性期，观察到IL-1表达细胞附近的许多破骨细胞，其中包含大的cytoplasmic，因此根尖周病变往往扩大。IL-1 β表达细胞的数量约为IL-1 α表达细胞的两倍，并且在同一时期，粘附分子ICAM-1和LFA-1在骨吸收表面附近的表达增加。另一方面，在慢性期有显著较少的IL-1 β表达细胞，因此没有观察到根尖周病变的显著扩大。此外，IL-1 β表达细胞位于远离骨表面，ICAM-1和LFA-1的表达在骨表面附近降低。IL-1 α和IL-1 β主要由巨噬细胞表达。这些结果表明，表达IL-1 β的巨噬细胞可能在骨细胞骨吸收的激活中起重要作用，这可能是由于实验性根尖周病变中骨吸收表面附近ICAM-1和LFA-1的表达增加。

In order to investigate the pathobiological mechanisms of bone destruction during apical periodontitis, we examined the relationship between the expression of interleukin-1 (IL-1) and that of adhesion molecules, such as intercellular adhesion molecule-1 (ICAM-1) and leukocyte function- associated antigen-1 (LFA-1), in rat periapical lesions using immunohistochemical methods. During the acute phase, IL-1-expressing cells were observed adjacent to many osteoclasts which contained large cytoplasms, and consequently the periapical lesions tended to expand. The number of IL-1 beta -expressing cells was about twice that of IL-1 alpha -expressing cells, and the expression of adhesion molecules ICAM-1 and LFA-1 were increased in the vicinity of the bone resorption surfaces during the same period. On the other hand, there were significantly less IL-1 beta -expressing cells during the chronic phase and consequently a significant expansion of periapical lesions was not seen. Furthermore, IL-1 beta -expressing cells were located far from the bone surfaces, and the expression of ICAM-1 and LFA-1 was decreased near the bone surfaces. Both IL-1 alpha and IL-1 beta were mainly expressed by macrophages. These results suggest that macrophages expressing IL-1 beta may play an important role in the activation of osteoclastic bone resorption and this may be due to the increase expression of ICAM-1 and LFA-1 in the vicinity of the bone resorption surfaces within experimental periapical lesions.