Abstract:

To observe expression of tumor necrosis factoralpha (TNFα) in ossification of the posterior longitudinal ligament of the spine (OPLL) and to explore its effect on biological characteristics of ligament cells. MethodsSpinal ligament specimens were obtained from nonossified sites of OPLL patients and nonOPLL patients. Eight OPLL cell lines (OL1OL8) and seven nonOPLL cell lines (NL1NL7) were established. The morphological and osteogenetical characteristics of the ligament cells cultured in vitro were detected.　Expression of TNFαin spinal ligament tissues was determined by an immunohistochemistical (IHC) technique. The effects of rhTNFα in different concentrations on the differentiation of cell lines were also detected. ResultsFour of eight OL cell lines expressed osteoblast phenotypes and the other cell lines expressed fibroblast phenotypes. TNFαexpressed in degenerative and ossified ligament tissues but not in normal or chondrified ligament tissues. TNFαhad different effects on different cell lines, which enhanced the ALP activity, DNA and collagen synthesis of all the cell lines. TNFα also induced OC secretion of all OL cell lines, only two NL cell lines secreted a low level of OC. ConclusionsCultured ligament cells from OPLL patients can express osteoblast phenotypes in vitro. TNFα plays an important role in the formation of OPLL.

Key words: Ossification； Posterior longitudinal ligament； Fib roblast； Osteoblast； Tumor necrosis factorα