[Study on the metabolism of cartilage matrix by the chondrocytes in osteoarthritic condylar cartilage].

OBJECTIVE: To study the characteristics of cellular metabolism of mandibular condylar chondrocytes in repairing state of osteoarthrosis and investigate its role in the pathogenesis of the disease. METHODS: Temporomandibular joint osteoarthrosis model of rabbits was created by the partial resection of joint disc and confirmed with histological diagnosis. The chondrocytes were harvested from osteoarthritic condylar cartilage in the repairing state and cultured in vitro under the monolayer culture condition. The cellular expression of cartilaginous matrix protein, collagenase and growth factors between the osteoarthritic chondrocytes and the normal controls were measured with RT-PCR technique to outline the basic feature of the osteoarthritic cells. RESULTS: The cultured cells were confirmed as chondrocytes with their ability of expression of collagen type II and Aggrecan. In the reactive repairing state of osteoarthrosis, the chondrocytes showed the imbalance of expression of ECM proteins, and increased expression of collagenase and endogenous growth factors such as IGF-1 and TGF-beta1. CONCLUSIONS: This study found the active anabolism of the chondrocytes within the osteoarthritic condylar cartilage and the imbalance synthesis of cartilage matrix. These repairing attempts by the osteoarthritic chondrocytes may be impossible to restore the primary homeostasis within the condylar cartilage.

[A novel cis-acting enhancer element between CKLF and CKLFSF1 genes].

AIM: To explore the roles of the CKLF gene and CKLFSF1 gene sequence (CCS) in transcriptional regulation. METHODS: The target gene fragment was amplified by PCR and then inserted into pGL3-basic and pGL3-SV40 containing luciferase reporter vector gene to construct pGL3-basic-CCS and pGL3-SV40-CCS. Using liposome-mediated method, four recombinant plasmids were respectively transfected into Hela cells. Transient expression was analyzed. RESULTS: The luciferase assay indicated that the no luciferase activity was detected in Hela cells transtected with pGL3-basic and pGL3-basic-CCS. However, the luciferase activity was doubled when pGL3-SV40-CCS was transfected into Hela cells. CONCLUTION: The CCS has no promoter activity, whereas some important cis-acting enhancer elements which modulate its downstream gene expression may exist within this sequence.