An Immuno-Electron Microscopic Study for Apoptosis and Expression of p53 on the Synovium of the Osteoarthritic Knee in Human

Lim, Hyoung Soo; Park, Kun Woo; Lee, Se Jeong; Hwang, Douk Ho

Abstract

This study was designed to observe the apoptosis and expression of p53 in the osteoarthritic synovial membrane compared with normal synovial membrane of human. The collected normal and osteoarthritic synovia were dissected and fixed for two hours (in 4% paraformaldehyde and 0.1% glutaraldehyde solution). In this study, TUNEL staining and immunocytochemical gold labeling techniques were used. In the immunocytochemical gold labeling techniques, primary antibodies which was to be monoclonal mouse anti-p53 were used. Donkey anti-mouse IgG tagged with 6 nm colloidal gold particles was used as the secondary antibody. The tissues were observed under JEOL 1200 EX-II transmission electron microscope. The results were as follows. 1. On TUNEL staining, normal synovium were not seen TUNEL positive signal cells. But, in the osteoarthritic synovium, few TUNEL positive cells were seen in synovial membrane and subsynovial layers. 2. On the transmission electron microscopic observation, normal synovium had 1~3 synovial cell layers, which had phagocytic synovial cells and secretory synovial cells. The osteoarthritic synovium had 2~5 synovial cell layers, which consisted with abnormally proliferated secretory synovial cells. These cells had heterochromatin in nucleus and well developed endoplasmic reticulum in the cytoplasm. 3. On the normal synovium of the human knee joint, p53 positive cells were not identified. But, in the osteoarthritic synovium of the human knee joint, p53 positive cells were identified. These cells were recognized secretory synovial cells and apoptotic cells. In the secretory synovial cells, the distributions of p53 were mitochondria and rough endoplasmic reticulum. In the apoptotic cells, p53 were marked on rough endoplasmic reticulum, which showed secretory synovial cells. On the basis of above findings, it is obvious that osteoarthritic synovial membrane has identified the apoptotic cells compared with normal synovium. These apoptotic cells might be identified as mainly secretory synovial cells and a few phagocytic synovial cells. The immunogold of p53 was marked at rough endoplasmic reticulum and in nucleus of apoptotic cells. Apoptosis in the osteoarthritic synovium seemed to be developed through p53 negative dependent pathway.