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Degradative enzymes such as matrix metalloproteinase (MMP) and disintegrin metalloproteinase with platelet thrombin-sensitive protein-like motifs (ADAMTS) play a key role in the development of osteoarthritis (OA). We aimed to investigate the effects of OA subchondral osteoblasts on the expression of ADAMTS4, ADAMTS5, MMP-3, MMP-9, and MMP-13 in chondrocytes and the regulation of mitogen-activated protein kinase (MAPK) signaling pathway.A rat knee OA model was constructed by cutting the anterior cruciate ligament of the knee joints, and normal rat articular cartilage chondrocytes (N-ACC), OA rat articular cartilage chondrocytes (O-ACC), normal subchondral bone osteoblasts (N-SBO), and OA subchondral bone osteoblasts (O-SBO) were isolated and extracted. The expressions of O-ACC and O-SBO COL1 and COL2 were detected respectively. Chondrocytes were identified by immunofluorescence of COL2 and toluidine blue staining, and osteoblasts were identified by COL1 immunofluorescence, alkaline phosphatase (ALP), and Alizarin Red staining. Gene expression of COL1, COL2, and aggrecan in normal chondrocytes and OA chondrocytes, and gene expression of osteoblast ALP and osteocalcin (OCN) were detected by RT-PCR to identify the two chondrocytes and the two osteoblast phenotypes. The constructing N-ACC group, O-ACC group, N-ACC + N-SBO group, N-ACC + O-SBO group, O-ACC + N-SBO group, O-ACC + O-SBO group, I + N-ACC + O-SBO group, and I + O-ACC + O-SBO group cell cultures, and the expression of ERK, ADAMTS4, ADAMTS5, MMP-3, MMP-9, and MMP-13 genes in chondrocytes cultured for 0, 24, 48, and 72 h were detected by RT-PCR. The protein expressions of pERK, ADAMTS4, ADAMTS5, MMP-3, MMP-9, and MMP-13 were detected by Western blot.· The X-ray showed that the knee joint space of the affected limb became narrow.. · The results of RT-PCR of COL2 and aggrecan gene in OA and normal chondrocytes suggest that the relative expression of COL2 in OA articular chondrocytes (0.24 ± 0.07) is significantly lower than that in normal cartilage (0.61 ± 0.07) (p 0.05). The relative expression of AGG (0.37 ± 0.16) in OA chondrocytes was significantly lower than that of normal chondrocytes AGG (1.30 ± 0.25) (p 0.05). The expression of COL1 was very low, and was not statistically significant.. · The results of RT-PCR of the osteoblast ALP and OCN gene indicated that gene expression of ALP (12.30 ± 1.17) and OCN (20.47 ± 4.19)was upregulated when compared with the relative expression of ALP (4.66 ± 0.71) (p 0.05) and OCN (12.17 ± 2.76) (p 0.05) in normal osteoblasts, indicating that osteoblasts of OA have greater osteogenic potential than normal osteoblasts.. · The expressions of ADAMTS4, ADAMTS5, MMP-3, MMP-9, and MMP-13 genes and proteins in OA chondrocytes or normal chondrocytes were basically unchanged when they were cocultured with normal osteoblasts. Indirect coculture of OA osteoblasts and chondrocytes could promote the expression of ADAMTS4, ADAMTS5, MMP-3, MMP-9, and MMP-13 genes and proteins in chondrocytes. Overexpression of ADAMTS and MMP in coculture systems can be reversed by MAPK-ERK inhibitors..· OA subchondral bone osteoblasts can promote the overexpression of ADAMTS and MMPs in chondrocytes.. · The ERK signaling pathway may be involved in the regulation of the effect of subchondral bone osteoblasts on chondrocytes..Enzyme wie Matrix-Metalloproteinase (MMP) und ADAMTS spielen eine Schlüsselrolle bei der Entstehung der Osteoarthritis (OA). Das Ziel der Studie war es, die Auswirkungen subchondraler Osteoblasten auf die Expression von ADAMTS4, ADAMTS5, MMP-3, MMP-9 und MMP-13 in Chondrozyten und die Regulation des Mitogen-aktivierten Proteinkinase-(MAPK-)Signalwegs in der OA zu untersuchen.Ein OA-Rattenknie-Modell wurde konstruiert, indem das vordere Kreuzband der Kniegelenke und normale Ratten-Chondrozyten (N-ACC), OA-Ratten-Chondrozyten (O-ACC), normale subchondrale Osteoblasten (N-SBO) und OA subchondrale Osteoblasten (O-SBO) isoliert und extrahiert wurden. Die Expressionen von O-ACC und O-SBO COL1 bzw. COL2 wurden nachgewiesen. Chondrozyten wurden durch Immunfluoreszenz von COL2 und Toluidinblau-Färbung identifiziert, Osteoblasten wurden durch COL1-Immunfluoreszenz, alkalische Phosphatase (ALP) und Alizarin-Rot-Färbung identifiziert. Die Genexpression von COL1, COL2 und Aggrecan in normalen Chondrozyten und OA-Chondrozyten sowie die Genexpression von Osteoblasten-ALP und Osteocalcin (OCN) wurden durch RT-PCR nachgewiesen, um die beiden Chondrozyten und die beiden Osteoblasten-Phänotypen zu identifizieren. Die aufbauende N-CC-Gruppe, O-ACC-Gruppe, N-ACC + NSBO-Gruppe, N-ACC + O-SBO-Gruppe, O-ACC + N-SBO-Gruppe, O-ACC + O-SBO-Gruppe, I + NACC + O-SBO-Gruppe und I + O-ACC + O-SBO-Gruppe-Zellkulturen und die Expression von ERK, ADAMTS4, ADAMTS5, MMP-3, MMP-9- und MMP-13- Gene in 0, 24, 48 und 72 h kultivierten Chondrozyten wurden durch RT-PCR nachgewiesen. Die Proteinexpressionen von pERK, ADAMTS4, ADAMTS5, MMP-3, MMP-9 und MMP-13 wurden durch Western Blot nachgewiesen.· Im Röntgenbild zeigte sich eine Kniegelenkspaltverengung.. · Die Ergebnisse der RT-PCR von COL2 und dem Aggrecan Gen in OA und normalen Chondrozyten legen nahe, dass die relative Expression von COL2 in artikulären Chondrozyten von OA (0,24 ± 0,07) signifikant niedriger ist als die in normalem Knorpel (0,61 ± 0,07) (p 0,05). Die relative Expression von AGG (0,37 ± 0,16) in OA-Chondrozyten war signifikant niedriger als die von normalen Chondrozyten-AGG (1,30 ± 0,25) (p 0,05). Die Expression von COL1 war sehr gering und statistisch nicht signifikant.. · Die Ergebnisse der RT-PCR des Osteoblasten-ALP- und OCN-Gens zeigten, dass die Genexpression von ALP (12,30 ± 1,17) und OCN (20,47 ± 4,19) im Vergleich zur relativen Expression von ALP (4,66 ± 0,71) (p 0,05) und OCN (12,17 ± 2,76) (p 0,05) bei normalen Osteoblasten hochreguliert war, was darauf hindeutet, dass Osteoblasten von OA ein größeres osteogenes Potenzial haben als normale Osteoblasten signifikant.. · Die Expressionen der ADAMTS4-, ADAMTS5-, MMP-3-, MMP-9- und MMP-13-Gene und -Proteine in OA-Chondrozyten oder normalen Chondrozyten waren im Wesentlichen unverändert, wenn sie mit normalen Osteoblasten kokultiviert wurden. Indirekte Kokultur von OA-Osteoblasten und Chondrozyten könnte die Expression der Gene und Proteine ADAMTS4, ADAMTS5, MMP-3, MMP-9 und MMP-13 in Chondrozyten fördern. Die Überexpression von ADAMTS und MMP in Kokultursystemen kann durch MAPK-ERK-Inhibitoren rückgängig gemacht werden..· Subchondrale Osteoblasten in OA Gelenken können die Überexpression von ADAMTS und MMPs in Chondrozyten fördern.. · Der ERK-Signalweg kann an der Regulation der Wirkung subchondraler Knochenosteoblasten auf Chondrozyten beteiligt sein..

Osteoporosis is a polygenic disorder and has been demonstrated to be associated with ~30 candidate genes, the majority of which have also been implicated in the regulation of bone mineral density (BMD). Vitamin D receptor (VDR) is the candidate gene that has been most extensively studied. Certain studies have reported that the VDR single nucleotide polymorphism ApaI is associated with the risk of osteoporosis in Caucasian and African women. However, this association has not yet been studied in postmenopausal Han Chinese women in the Xinjiang area. In the present study, ApaI polymorphisms of VDR were defined by polymerase chain reaction-restriction fragment length polymorphism, in order to analyze the distribution of ApaI polymorphisms in postmenopausal Han Chinese women from Xinjiang. BMD was measured by dual energy X-ray absorptiometry at the lumbar spine (L2-4), Ward's triangle, great trochanter and femoral shaft. A total of 336 women were included in this study. The genotype distribution of ApaI was consistent with the Hardy-Weinberg equilibrium (all P>0.05). There were no significant differences in ApaI genotype frequencies between the 90 cases in the osteoporosis group and 246 cases in the non-osteoporosis group (P=0.946). Meanwhile, it was identified that BMD values of the tested locations were negatively correlated with age (P0.05). In conclusion, the present study identified no significant association of the common VDR polymorphism ApaI with BMD at several skeletal sites in postmenopausal Han Chinese women in the Xinjiang area. Age was negatively correlated with BMD at different sites and identified as a risk factor; while BMI was positively correlated with BMD and identified as a protective factor.