BACKGROUNDPressure therapy improves hypertrophic scar healing, but the mechanisms for this process are not well understood. We sought to investigate the differential expression of matrix metalloproteinases (Mmps) and collagen in posttraumatic hypertrophic scar tissue with mechanical pressure and delineate the molecular mechanisms of pressure therapy for hypertrophic scars.

METHODSFibroblast lines of normal skin and scar tissue were established and a mechanical pressure system was devised to simulate pressure therapy. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting assays were used to compare differences in the mRNA and protein expression of Mmps and collagen in scar fibroblasts before and after pressure therapy.

RESULTSThe expression differed between the hypertrophic scar cell line and the normal cell line. RT-PCR assays showed that Collagen I, highly expressed in the hypertrophic scar cell line, decreased significantly after pressure therapy. Mmp2, Mmp9, and Mmp12 expression in the hypertrophic scar tissue increased significantly after pressure therapy (P < 0.05). Western blotting assays further revealed that Mmp9 and Mmp12 expression increased significantly in the hypertrophic scar tissue after pressure therapy (P < 0.05) but not Mmp2 expression (P > 0.05).

CONCLUSIONMechanical pressure induces degradation of Collagen I in hypertrophic scar tissue by affecting the expression of Mmp9 and Mmp12.

Cell Line ; Cicatrix, Hypertrophic ; enzymology ; metabolism ; Collagen Type I ; genetics ; metabolism ; Humans ; Matrix Metalloproteinase 12 ; genetics ; metabolism ; Matrix Metalloproteinase 2 ; genetics ; metabolism ; Matrix Metalloproteinase 9 ; genetics ; metabolism

OBJECTIVETo study the changes of metalloproteinases 1, 2, 13 in granulation wound after the treatment of vacuum-assisted closure (VAC).

METHODSThe chronic wounds in 5 patients were treated with VAC. The expressions of MMP-1, 2, 13 in the granulation tissues of the chronic wounds were determined and quantified using RT-PCR technique before and at 1, 4, 7 days after the treatment.

RESULTSThe MMP-1, 13 mRNA showed obvious decrease, with the steepest variation of MMP-13. The MMP-2 mRNA also showed a decreased tendency, though in an undulatory fashion.

CONCLUSIONVAC can promote healing of chronic wounds through depressing the expressions of MMP-1, 2, 13 mRNA and protein synthesis, depressing the degradations of collagen and gelatin.

Collagen ; metabolism ; Humans ; Matrix Metalloproteinase 1 ; metabolism ; Matrix Metalloproteinase 13 ; metabolism ; Matrix Metalloproteinase 2 ; metabolism ; Negative-Pressure Wound Therapy ; Polymerase Chain Reaction ; Time Factors ; Wound Healing

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

AIMTo explore the changes of MMP-2/9 protein expression and excitation in brain of repetitive hypoxic mice.

METHODSThe biochemistry techniques of SDS-PAGE, Western bolt and Gel Goc Image Analysis System were applied to determine the level of MMP-2 and MMP-9 expression and activation in cortex and hippocampus of mice. The animals were randomly divided into 5 groups: the normal control group (H0), acute hypoxic (H1, hypoxic exposure once), repetitive hypoxic groups (H2-H4, repetitive hypoxia for 2-4 runs respectively).

RESULTS(1) The MMP- 2 expression level was increased first then decreased in hippocampus and the significant decrease was found in H4 group (P < 0.05, n=6), but no significant changes among the 5 groups in cortex. In addition, no activated form of 66 kD MMP-2 had been detected both in hippocampus and cortex. (2) Along with the development of brain hypoxic preconditioning, the level MMP-9 protein expression also increased first then decreased gradually in hippocampus, and the significant changes were found both in H1 and H4 groups (P < 0.05, n=7 for each group). The same trace of changes was also found in the activation of MMP-9 (include 82 and 78 kD forms) in hippocampus, and the significance both in H1 and H4 (P < 0.05, n=7 for each group) were detected. However, there was not any significant change in the level of MMP-9 protein expression or activation to be found in cortex.

CONCLUSIONThese results suggested that MMP-2 and MMP-9 might play certain role in the development of cerebral hypoxic preconditioning, the different changes of MMP-2/9 protein expression and activation both in cortex and hippocampus might be involved in their selective vulnerability to hypoxia.

Animals ; Hypoxia, Brain ; metabolism ; Ischemic Preconditioning ; Matrix Metalloproteinase 2 ; metabolism ; Matrix Metalloproteinase 9 ; metabolism ; Mice ; Mice, Inbred BALB C

OBJECTIVE: To investigate the expression of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) in multiple myeloma (MM) patients, and analyze the effect of doxycycline (DOX) on the expression of MMP-2 and MMP-9 in MM cells. METHODS: The peripheral blood and bone marrow samples of MM patients were collected, and the patients were divided into three groups: newly diagnosed group, remission group and relapsed/refractory group, while the peripheral blood samples of 34 health people and the bone marrow samples of 17 IDA patients were selected as normal control and control group. The levels of MMP-2 and MMP-9 were detected by ELISA. The protein levels of MMP-2 and MMP-9 in H929 cells treated by different concentrations of DOX were analyzed by Western blot. After H929 cells was treated by Akt inhibitor MK-2206 2HCl in combination with DOX, Western blot was used to detect the levels of MMP-2 and MMP-9. RESULTS: The levels of MMP-2 and MMP-9 in newly diagnosed MM patients were higher than those in control (P<0.05), while for the patients in the remission group were decreased, but still higher than those in control. The levels of MMP-2 and MMP-9 were increased again for the patients in relapsed/refractory group, and showed no significant difference as compared with those in newly diagnosed group. The levels of MMP-2 and MMP-9 could be inhibited by 10 mg/L and 15 mg/L DOX treated by H929 cell. The protein levels of MMP-2 and MMP-9 showed no altered in H929 cells treated by 5 nmol/L MK-2206 2HCl alone. DOX exerted more profound inhibitory effect to MMP-2 and MMP-9 expression in H929 cells when Akt inhibitor MK-2206 2HCl was combined with DOX. CONCLUSION The levels of MMP-2 and MMP-9 are increased in MM patients and related to the disease status of MM. DOX can inhibit the expression of MMP-2 and MMP-9 in MM cells, and antagonizing its activation of Akt signaling pathway can further enhance the inhibitory effect.
Doxycycline/pharmacology* ; Humans ; Matrix Metalloproteinase 2/metabolism* ; Matrix Metalloproteinase 9/metabolism* ; Multiple Myeloma/metabolism* ; Proto-Oncogene Proteins c-akt

OBJECTIVETo discuss the function of MMP-9, MMP-2 in the remodeling bone tissue around implant during unloaded period.

METHODSAt the anterior of the maxilla and mandibular of the Beagle dog, implants were placed at different periods, so the implant specimens of different periods were obtained after dogs were killed. The implant specimens were removed, fixed in 4% paraformaldehyde for 24 hours at 4 degrees C, decalcified with 10% EDTA at pH 7.2, embedded in paraffin wax and sectioned. The observation of the expression changes of the MMP-2, MMP-9 in the milien bone tissue of the implant at different periods were taken by immunohistochemical staining.

RESULTSMatrix metalloprotainase (MMP-9) was mostly expressed at the peripheral cytoplasmic of osteoclast, macrophage, lining cell and fibroblast. MMP-2 was mostly expressed at the peripheral cytoplasmic of osteoblast, fibroblast, some osteoclast also expressed this enzyme.

CONCLUSIONMMP-2 and MMP -9 have an important function at the injured bone absorption, healing and bone remodeling after dental implant placement.

Animals ; Bone Remodeling ; Dental Implantation, Endosseous ; Dental Implants ; Dogs ; Mandible ; Matrix Metalloproteinase 2 ; metabolism ; Matrix Metalloproteinase 9 ; metabolism ; Maxilla

Objective To explore the effect of overwork (OW) on extracellular matrix of arterial vessel wall in rats. Methods Random number grouping method was employed to assign 18 Sprague-Dawley rats into three groups(n=6):the control group(no special treatment),group OW(forced swimming twice a day for 15 days),and sleep deficiency(SD)+OW group(in addition to forced swimming twice a day,the rats were put on the platforms in water to limit sleep for 15 days).On the 16th day,the abdominal aorta and common carotid artery were collected after blood sampling from heart under deep anesthesia.A part of the abdominal aorta sample was taken for Masson staining of collagen fiber,and Verhoeff-Van Gieson staining was carried out for the elastic fiber of common carotid artery.Image J was employed for the quantitative analysis of collagen fiber and elastic fiber content.The expression of collagen 1(Col-1) protein was quantified by immunohistochemistry and the ultrastructure of vascular matrix was examined by transmission electron microscopy.The other part of the abdominal aorta sample was used to determine the mRNA levels of matrix metalloproteinase(MMP)-1,MMP-2,MMP-9,tissue inhibitor of metalloproteinases-1(TIMP-1),and Col-1 by quantitative real-time polymerase chain reaction. Results Compared with that in control group,the content of collagen fiber in groups OW and SD+OW had no significant change(all P>0.05);the content of elastic fiber in groups OW and SD+OW decreased(all P<0.001) and had no significant difference between each other(P>0.05).The vascular vessel wall of group OW showed slight fiber breakage,while that of group SD+OW presented wormhole-like or spongy fiber fragmentation.The mRNA levels of MMP-1 and MMP-2 in groups OW and SD+OW had no significant difference between each other(P>0.05) but were higher than that in control group(all P<0.001).The mRNA levels of MMP-9 and TIMP-1 had no significant difference among the three groups(all P>0.05).Groups OW and SD+OW had lower mRNA level(all P<0.001) and protein level(all P<0.001) of Col-1 than control group,while the mRNA and protein levels of Col-1 had no significant difference between groups OW and SD+OW(P>0.05). Conclusion OW can reduce the content of Col-1 and elastic fibers in the extracellular matrix of arterial vessels,destroy the elastic lamina of vascular wall,up-regulate the expression of MMP-1 and MMP-2,thereby injuring arterial vessels.
Animals ; Collagen Type I ; Extracellular Matrix/metabolism* ; Matrix Metalloproteinase 1/metabolism* ; Matrix Metalloproteinase 2/metabolism* ; Matrix Metalloproteinase 9/metabolism* ; RNA, Messenger/genetics* ; Rats ; Rats, Sprague-Dawley ; Tissue Inhibitor of Metalloproteinase-1/metabolism*

Female ; Hepatitis, Chronic ; metabolism ; Humans ; Immunohistochemistry ; Liver Cirrhosis ; metabolism ; Male ; Matrix Metalloproteinase 2 ; analysis ; Tissue Inhibitor of Metalloproteinase-2 ; analysis

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

Animals ; Extracellular Matrix ; metabolism ; Humans ; Kidney Glomerulus ; pathology ; Matrix Metalloproteinase 2 ; analysis ; physiology ; Sclerosis