With the effects of the mechanics and biological factors, the imbalance between the degradation and synthesis of chondrocyte, extracelluar matrix and subchondral bone leads to the osteoarthritis. The imbalance between MMPs and TIMPs caused by biomechanical abnormality is the key factor of osteoarthritis. This review will focus on the stress and their roles in the metabolism of the cartilage matrix.
Cartilage ; metabolism ; Humans ; Matrix Metalloproteinases ; metabolism ; Osteoarthritis ; metabolism ; Stress, Mechanical ; Tissue Inhibitor of Metalloproteinases ; metabolism

OBJECTIVETo study the effect of matrix metalloproteinase 2 (MMP-2), membrane type 1 MMP (MT1-MMP) and tissue inhibitor of metalloproteinase 2 (TIMP-2) expressions on the in vitro invasive capacity of acute monocytic leukemia SHI-1 cells.

METHODSSHI-1, NB4, K562, M937 and THP-1 human leukemia cell lines were cultured in vitro. The mRNA and protein expressions of TIMP-2, MMP-2 and MT1-MMP in different cells were detected by quantitative RT-PCR and western blot. A retroviral vector carrying human TIMP-2 cDNA was constructed and transfected into SHI-1 cells. Three subclone cells (S1, S2 and S3) were screened by G418 and selected by limiting dilution. RNA interference (RNAi) was used to knock down the expression of MMP-2, MT1-MMP and TIMP-2. Cell invasion capacity was performed through a reconstituted human basement membrane assays. Zymography was used to analyze the expression of MMP-2 in the supernatant of co-culture.

RESULTSThe expressions of MMP-2, MT1-MMP and TIMP-2 in SHI-1 cells were higher than that in other leukemic cells at both mRNA and protein levels (P < 0.05). The amount of proMMP-2 and activated MMP-2 in the conditioned media from SHI-1 cells co-cultured with bone marrow stromal cells (BMSCs) was more than that from other cells (P < 0.05). The in vitro invasive capacity of SHI-1 cells were higher than that of other cells (P < 0.05). The mRNA levels of TIMP-2 were increased by about 3 fold, 2 fold and 1.5 fold in S1, S2 and S3 cells, respectively (P < 0.05), while the protein levels were by about 2.6 fold, 1.5 fold and 1.3 fold than that of SHI-1 cells, respectively (P < 0.01). The invasion rates of subclone cells demonstrated a 1.5 - 2.5 fold' elevation (P < 0.05) and activated MMP-2 from their supernatants increased by 1.5 - 2.0 fold (P < 0.01). The knock-down efficiency of siRNA was 85% to 98%. The down-regulation of TIMP-2, MMP-2 and MT1-MMP decreased the invasion rates of SHI-1 cells by 60% - 70%, 50% - 60% and 40% - 50%, respectively (P < 0.05). No activated MMP-2 in the supernatants from any knock-down cells could be found.

CONCLUSIONSSHI-1 cells constitutively overexpress MMP-2, MT1-MMP and TIMP-2 at both mRNA and protein levels. After co-cultured with BMSCs the SHI-1 cells increased MMP-2 activation and cell invasion. An increase of TIMP-2 expression in SHI-1 cells reflects an activating effect on cells invasion and MMP-2 activation.

Coculture Techniques ; Humans ; Leukemia, Monocytic, Acute ; Matrix Metalloproteinase 2 ; metabolism ; Matrix Metalloproteinases, Membrane-Associated ; RNA, Messenger

OBJECTIVETo evaluate the effect of dentin matrix metalloproteinase (MMP) on the degradation of root dentin collagen.

METHODSRoot dentin powder was demineralized with acetic acid (pH 4.0) at 4 degrees C for 14 d, then dialysed and centrifuged. Precipitation was divided into 7 groups, with 6 samples in each group, and each sample was 50.0 mg. One milliliter artificial saliva with a different reagent was added in each sample respectively. The reagents were 2 mmol/L APMA (MMP activator), 2 mmol/L EDTA, 100 mmol/L EDTA, 200 mmol/L EDTA, 0.2% and 0.02% chlorhexidine (MMP inhibitor), and the blank artificial saliva was taken as control. The amount of degraded collagen of each sample was determined with hydroxyproline assay kit. Scanning electron microscope was employed to observe the morphological and structural changes of root dentin which was demineralized or put into artificial saliva after being demineralized.

RESULTSThe mean amount of degraded collagen in APMA group was significantly higher than that in the blank group (P < 0.05). The mean amount of degraded collagen in 2 mmol/L, 100 mmol/L, 200 mmol/L EDTA, 0.02% and 0.2% chlorhexidine groups was dramatically lower than that of the APMA group and the blank (P < 0.01). SEM observation indicated that the structural integrity of the collagen network on root surface dentin still existed in root dentin surface after being demineralized alone, while collagenous fibril was destructed and the structural integrity on root dentin surface disappeared after being demineralized and treated by artificial saliva.

CONCLUSIONSMMP in root dentin can degrade root dentin collagen after being activated at low pH followed by neutralization. The results suggest that host MMP may play an important role in the process of dentin caries formation.

Collagen ; metabolism ; Dental Caries ; enzymology ; Dentin ; metabolism ; Humans ; In Vitro Techniques ; Matrix Metalloproteinases ; metabolism ; Tooth Root ; metabolism

Adult ; Diabetes, Gestational ; metabolism ; Female ; Humans ; Matrix Metalloproteinases ; metabolism ; Placenta ; enzymology ; Pregnancy

OBJECTIVETo observe the effects of hemoperfusion on oxidative stress status and the levels of matrix metallo proteinase (MMP-2, MMP-9), tissue inhibitor of metalloproteinase (TIMP-1) in lungs, livers and kidneys in paraquat poisoning rabbits, and to explore the mechanism of therapeutic effects induced by HP on acute paraquat poisoning.

METHODSSeventy eight rabbits were randomly divided into normal control group (N group, n=6), exposure groups (PQ group, n=24), hemoperfusion treatment group (HP treatment group, n= 24) and blank control group (HP group, n=24). The PQ, HPQ and HP groups were divided into 4 observation time groups (1, 3, 7 and 21 d). N group was exposed to 5 ml normal saline and PQ group was exposed to 50 mg/kg PQ by oral gavage. In 1 h after PQ exposure, HPQ group was exposed to the activated carbon hemoperfusion for 2 h. The content or activity of MDA, SOD and GSH-Px in lungs, livers and kidneys were detected, the expression levels of MMP-2, MMP-9 and TIMP-1 were measured with immunohistochemical SP method for all groups.

RESULTSThe contents of MDA in lungs, livers and kidneys of PQ and HPQ groups decreased and the activities of SOD and GSH-Px in lungs, livers and kidneys of PQ and HPQ groups increased with observation time. The expression levels of MMP-2, MMP-9 and TIMP-1 in PQ and HPQ groups enhanced on the first day, PQ group was most obvious. Along with the observation time extended, all kinds of positive expression were still high. Compared with normal control group, the activities of serum SOD and GSH-Px in PQ and HPQ groups declined significantly, but the contents of serum MDA increased; the expression levels of MMP-2, MMP-9 and TIMP-1 in lung, liver and kidney tissues increased obviously, the ration between MMP-9 and TIMP-1 significantly increased (P < 0.05). Compared with PQ group, the activities of SOD and GSH-Px in HPQ group significantly increased, the content of MDA declined, the expression levels of MMP-2, MMP-9 and TIMP-1 in lung, liver and kidney tissues declined obviously, the ration between MMP-9 and TIMP-1 significantly declined, but higher than N group, the differences were statistically significant (P < 0.05).

CONCLUSIONThe oxidative stress and MMPs may be involved in the pathogenesis of tissue injuries induced by paraquat. The treatment with HP could obviously reduce oxidative stress and the expression levels of MMP-2, MMP-9 and TIMP-1, enhance the ration between MMP-9 and TIMP-1. So HP treatment could play a role in rescuing the PQ poisoning and protecting the organs function.

Animals ; Female ; Hemoperfusion ; Male ; Matrix Metalloproteinase 2 ; metabolism ; Matrix Metalloproteinase 9 ; metabolism ; Matrix Metalloproteinases ; metabolism ; Oxidative Stress ; Paraquat ; poisoning ; Rabbits ; Tissue Inhibitor of Metalloproteinase-1 ; metabolism

Diabetic Foot ; enzymology ; physiopathology ; Humans ; Matrix Metalloproteinases ; metabolism ; Wound Healing ; physiology

The physiological reconstruction of bone is strictly dependent on bone resorption. Bone resorption is believed to be a complicated molecular reaction process that occurs in the microcircumstance of bone tissue. A lot of enzymes and factors take part in this process, yet there are not enough data with reference to the activation of osteoclast, resorption of bone matrix, regulation of bone resorption. In this paper we review the importance of matrix metalloproteinases (MMPs) in transfer of osteoclast and degradation of bone matrix, and the function of receptor activator of NF-kappaB-ligand (RANKL) and osteoprotegerin (OPG) in regulation of bone resorption.
Bone Resorption ; Humans ; Matrix Metalloproteinases ; metabolism ; Osteoclasts ; physiology ; Osteoprotegerin ; physiology ; RANK Ligand ; physiology

AIMTo investigate the relationship between the expression of MMP-2, MMP-9, TIMP-1 and TIMP-2 and ECM accumulation in rat left ventricle in a mechanical unloaded heart model.

METHODS12-week-old male Lewis rats were subjected to abdominal heterotopic heart transplantation to achieve pressure and volume unloading(mechanical unloading). Age and sex matched in situ heart of Lewis rats were used as control. Collagen volume fraction(CVF) was analyzed by picrosiris-red staining plus polarized microscopy. MMP-2 and -9 gelatinolytic activity were measured by gelatin-zymography. mRNA level of MMP-2, MMP-9, TIMP-1 and TIMP-2 were measured by real-time quantitative PCR. TIMP-1 and TIMP-2 protein level were measured by immunoblotting.

RESULTSMyocardial cross-sectional area of transplanted heart was significantly reduced, and accompanied by excessive ECM deposition (CVF 5.22% +/- 1.6% vs. 2.21% +/- 0.9%, P < 0.05) compared to in situ heart. MMP-2 and MMP-9 activity were significantly increased, as well as mRNA level of MMP-2, MMP-9, TIMP-1 and TIMP-2 compared to in situ heart. TIMP-1 and TIMP-2 protein level in mechanically unloaded heart were significantly upregulated compared to in situ heart, especially for TIMP-1.

CONCLUSIONMechanical unloading of left ventricle may lead to excessive ECM deposition, accompanied by imbalance between MMPs and TIMPs system, especially the upregulation of TIMPs.

Animals ; Extracellular Matrix ; metabolism ; Gelatinases ; metabolism ; Heart Transplantation ; physiology ; Heart-Assist Devices ; Male ; Matrix Metalloproteinases ; metabolism ; RNA, Messenger ; metabolism ; Rats ; Rats, Inbred Lew ; Tissue Inhibitor of Metalloproteinases ; metabolism ; Transplantation, Heterotopic ; physiology ; Ventricular Dysfunction, Left ; metabolism

OBJECTIVETo study the relationship between atrial structural remodeling and the expressions of matrix metalloproteinase (MMPs) and their tissue inhibitors (TIMPs) in atrial fibrillation (AF).

METHODSBiopsy samples of the right atrial appendages were collected from 20 patients with sinus rhythm and 30 with AF undergoing heart valve replacement surgery for rheumatic heart diseases. All the patients received echocardiographic examination preoperatively. MMP-1, -3, -7, -9 and TIMP-1, -2, -3, -4 protein expressions were detected by immunohistochemistry and RT-PCR.

RESULTSCompared with those in patients with sinus rhythm, the AF patients had significantly increased left and right atrial diameters and mRNA levels of MMP-3, -7, -9 and TIMP-1, -2, -3, -4 (P<0.01). MMP-1 expression also showed an increase in AF patients, but the difference was no statistically significant from that in patients with sinus rhythm.

CONCLUSIONThe expressions of MMP-1, -3, -7, -9 and TIMP-1, -2, -3, -4 increase in fibrillating atrial tissue, which may contribute to atrial structural remodeling and atrial dilatation in AF patients.

Adult ; Aged ; Atrial Fibrillation ; enzymology ; pathology ; physiopathology ; Female ; Humans ; Male ; Matrix Metalloproteinases ; genetics ; metabolism ; Middle Aged ; Tissue Inhibitor of Metalloproteinases ; genetics ; metabolism

OBJECTIVETo investigate the expression of occludin, ZO-1, MMP-2, and MMP-9 in cerebral microvasculature following Pulse Electromagnetic Field (PEMF) induced BBB permeability change.

METHODSSprague-Dawley rats were randomized into PEMF and sham exposed groups (n = 8). After exposure to PEMF at 0.5, 1, 3, 6, and 12 h, BBB permeability was measured by Evans-Blue extravasation. The expression of occludin, ZO-1, MMP-2, and MMP-9 were detected by real-time quantitative reverse transcriptase PCR and western blotting. MMP-2 and MMP-9 activity were detected by EnzChek gelatinase assay.

RESULTSCompared with the sham group, PEMF exposure led to increased permeability of the BBB to EB, which was prolonged after exposure. BBB permeability became progressively more severe, and recovered at 6 h. The gene and protein expression of occludin and ZO-1 were significantly decreased, while MMP-2 and MMP-9 expression were significantly increased after exposure to PEMF. All levels of expression recovered 12 h following PEMF.

CONCLUSIONChanges to BBB permeability were related to the alteration expression of tight junction proteins and matrix metalloproteinase after exposure to PEMF.

Animals ; Blood-Brain Barrier ; Electromagnetic Fields ; Male ; Matrix Metalloproteinases ; metabolism ; Proteins ; metabolism ; Rats ; Rats, Sprague-Dawley ; Tight Junctions ; metabolism