The clinical treatment of joint contracture due to immobilization remains difficult. The pathological changes of muscle tissue caused by immobilization-induced joint contracture include disuse skeletal muscle atrophy and skeletal muscle tissue fibrosis. The proteolytic pathways involved in disuse muscle atrophy include the ubiquitin-proteasome-dependent pathway, caspase system pathway, matrix metalloproteinase pathway, Ca-dependent pathway and autophagy-lysosomal pathway. The important biological processes involved in skeletal muscle fibrosis include intermuscular connective tissue thickening caused by transforming growth factor-β1 and an anaerobic environment within the skeletal muscle leading to the induction of hypoxia-inducible factor-1α. This article reviews the progress made in understanding the pathological processes involved in immobilization-induced muscle contracture and the currently available treatments. Understanding the mechanisms involved in immobilization-induced contracture of muscle tissue should facilitate the development of more effective treatment measures for the different mechanisms in the future.
Atrophy ; Autophagy ; Calcium ; metabolism ; Caspases ; metabolism ; Connective Tissue ; metabolism ; pathology ; Contracture ; etiology ; metabolism ; pathology ; therapy ; Fibrosis ; Humans ; Immobilization ; adverse effects ; Joints ; Lysosomes ; metabolism ; Matrix Metalloproteinases ; metabolism ; Muscle, Skeletal ; metabolism ; pathology ; Proteasome Endopeptidase Complex ; metabolism ; Proteolysis ; Signal Transduction ; physiology ; Transforming Growth Factor beta1 ; metabolism ; Ubiquitin ; metabolism

BackgroundCorneal stromal cells (CSCs) are components of the corneal endothelial microenvironment that can be induced to form a functional tissue-engineered corneal endothelium. Adipose-derived mesenchymal stem cells (ADSCs) have been reported as an important component of regenerative medicine and cell therapy for corneal stromal damage. We have demonstrated that the treatment with ADSCs leads to phenotypic changes in CSCs in vitro. However, the underlying mechanisms of such ADSC-induced changes in CSCs remain unclear.

MethodsADSCs and CSCs were isolated from New Zealand white rabbits and cultured in vitro. An Exosome Isolation Kit, Western blotting, and nanoparticle tracking analysis (NTA) were used to isolate and confirm the exosomes from ADSC culture medium. Meanwhile, the optimal exosome concentration and treatment time were selected. Cell Counting Kit-8 and annexin V-fluorescein isothiocyanate/propidium iodide assays were used to assess the effect of ADSC- derived exosomes on the proliferation and apoptosis of CSCs. To evaluate the effects of ADSC- derived exosomes on CSC invasion activity, Western blotting was used to detect the expression of matrix metalloproteinases (MMPs) and collagens.

Results:ADSCs and CSCs were successfully isolated from New Zealand rabbits. The optimal concentration and treatment time of exosomes for the following study were 100 μg/ml and 96 h, respectively. NTA revealed that the ADSC-derived exosomes appeared as nanoparticles (40-200 nm), and Western blotting confirmed positive expression of CD9, CD81, flotillin-1, and HSP70 versus ADSC cytoplasmic proteins (all P < 0.01). ADSC-derived exosomes (50 μg/ml and 100 μg/ml) significantly promoted proliferation and inhibited apoptosis (mainly early apoptosis) of CSCs versus non-exosome-treated CSCs (all P < 0.05). Interestingly, MMPs were downregulated and extracellular matrix (ECM)-related proteins including collagens and fibronectin were upregulated in the exosome-treated CSCs versus non-exosome-treated CSCs (MMP1: t = 80.103, P < 0.01; MMP2: t = 114.778, P < 0.01; MMP3: t = 56.208, P < 0.01; and MMP9: t = 60.617, P < 0.01; collagen I: t = -82.742, P < 0.01; collagen II: t = -72.818, P < 0.01; collagen III: t = -104.452, P < 0.01; collagen IV: t = -133.426, P < 0.01, and collagen V: t = -294.019, P < 0.01; and fibronectin: t = -92.491, P < 0.01, respectively).

Conclusion:The findings indicate that ADSCs might play an important role in CSC viability regulation and ECM remodeling, partially through the secretion of exosomes.

Adipose Tissue ; cytology ; Animals ; Cell Proliferation ; physiology ; Cell Survival ; physiology ; Cells, Cultured ; Exosomes ; metabolism ; Extracellular Matrix ; metabolism ; Fibroblasts ; cytology ; metabolism ; Matrix Metalloproteinases ; metabolism ; Mesenchymal Stromal Cells ; cytology ; metabolism ; Rabbits

The suitable experimental animal model is important in research of pathogenesis and therapeutic strategies of diabetic foot ulcer, and the murine model is the most commonly used one at present. It can be divided into two types: the animal model simulating pathological conditions and the model simulating clinical symptoms. This article reviews the current research progress on the mechanisms of diabetic ulcer pathogenesis, and relevant treatment strategies, including the inhibition of matrix metalloproteinases (MMPs) expression, promotion of angiogenesis and anti-inflammatory therapy.
Animals ; Anti-Inflammatory Agents ; therapeutic use ; Diabetic Foot ; etiology ; genetics ; therapy ; Disease Models, Animal ; Humans ; Matrix Metalloproteinase Inhibitors ; therapeutic use ; Matrix Metalloproteinases ; genetics ; metabolism ; Mice ; Neovascularization, Physiologic ; physiology

PURPOSE: To determine the effect of exogenous nitric oxide (NO) on the migration of trabecular meshwork (TM) cells and its association with expression of matrix metalloproteinases (MMPs). METHODS: Primary human TM cells treated with 1 or 10 microM S-nitroso-N-acetyl-penicillamine (SNAP) and examined for changes in adherence. TM cells were seeded onto transwell culture inserts, and changes in their migratory activity were quantified. Reverse transcription polymerase chain reaction was performed to determine the relative changes in mRNA expression of MMPs and tissue inhibitor of metalloproteinases (TIMPs). RESULTS: Treatment with SNAP did not significantly suppress TM cell adhesion or migration (p > 0.05). Treatment of TM cells with 10 microM SNAP decreased expression of MMP-2 and increased expression of membrane type MMP-1 and TIMP-2. Treatment with interleukin-1alpha triggered MMP-3 expression but did not exert significant effects on MMP-3 activation in response to SNAP. CONCLUSIONS: These data suggest that NO revealed no significant effect on the migration of TM cells because NO decreased MMP-2 and increased TIMP-2 expression. Although expression of certain MMPs and TIMPs change in response to NO donors, NO may modulate trabecular outflow by changing the cellular production of extracellular matrix without having a significant effect on the migration of TM cells.
Cell Movement/*drug effects ; Cell Survival/drug effects ; Cells, Cultured ; DNA Primers/chemistry ; Gene Expression Regulation, Enzymologic/*physiology ; Humans ; Matrix Metalloproteinases/*genetics ; Nitric Oxide Donors/*pharmacology ; RNA, Messenger/genetics ; Real-Time Polymerase Chain Reaction ; S-Nitroso-N-Acetylpenicillamine/*pharmacology ; Tissue Inhibitor of Metalloproteinase-2/*genetics ; Trabecular Meshwork/cytology/*drug effects/enzymology

OBJECTIVEThis study aimed to investigate the effects of in vitro continuous passaging on the morphological phenotype and differentiation characteristics of mouse hyaline chondrocytes, as well as on the balance of the extracellular matrix (ECM).

METHODSEnzymatic digestion was conducted to isolate mouse hyaline chondrocytes, which expanded over five passages in vitro. Hematoxylin-eosin stain was used to show the changes in chondrocyte morphology. Semi-quantitative polymerase chain reaction was performed to analyze the mRNA changes in the marker genes, routine genes, matrix metalloproteinases (MMPs), and tissue inhibitors of MMPs (TIMPs) in chondrocytes. Zymography was carried out to elucidate changes in gelatinase activities.

RESULTSAfter continuous expansion in vitro, the morphology of round or polygonal chondrocytes changed to elongated and spindled shape. The expression of marker genes significantly decreased (P < 0.05), and it was almost negatively expressed by P5 chondrocytes. By contrast, the down regulation of routine genes was insignificant. The gene expression levels of MMPs and TIMPs both decreased (P < 0.05), but the change in MMP-1 and TIMP-1 was not statistically significant (P > 0.05). Meanwhile, the ratio of MMPs/TIMPs was altered. At the protein level, the activities of gelatinases decreased after passaging, especially for P4 and P5 chondrocytes (P < 0.05).

CONCLUSIONSerially passaged chondrocytes dedifferentiated and lost specific phenotypic characteristics during in vitro expansion culture. Simultaneously, the anabolism and catabolism of the cartilage ECM became uncontrollable and led to the imbalance of ECM homeostasis. When hyaline chondrocytes are applied in research on relevant diseases or cartilage tissue engineering, P0-P2 chondrocytes should be used.

Animals ; Cartilage ; Cell Differentiation ; Cells, Cultured ; Chondrocytes ; physiology ; Cytoskeleton ; Extracellular Matrix ; Gelatinases ; Gene Expression ; Hyalin ; physiology ; Matrix Metalloproteinase 1 ; Matrix Metalloproteinases ; Mice ; RNA, Messenger ; Tissue Engineering ; Tissue Inhibitor of Metalloproteinase-1 ; Tissue Inhibitor of Metalloproteinases

Tenascin-C (TNC) is an extracellular matrix glycoprotein, which is usually highly expressed in embryonic tissues and tumor tissues, but is not expressed or just lowly expressed in mature tissues. TNC is involved in various complex signaling pathways during tumor metastasis, especially through modulating FAK, RhoA, Wnt and Notch pathways by interacting with syndecan-4, integrin α5β1, matrix metalloproteinases (MMPs) and vascular endothelial growth factor (VEGF). As a result, TNC affects epithelial mesenchymal transition, tumor cell adhesion, proliferation and angiogenesis, which eventually enhances the invasion and metastasis ability of many tumors. Further studies have demonstrated that TNC could be used as prognosis or metastasis marker of patients with malignant tumor.
Cell Adhesion ; Humans ; Integrins ; Matrix Metalloproteinases ; Neoplasm Metastasis ; Neoplasms ; Neovascularization, Pathologic ; Signal Transduction ; Tenascin ; physiology ; Vascular Endothelial Growth Factor A

Chronic spinal cord compression is the common clinical prognosis with various outcomes, but the affecting factors and mechanisms still remain unexplored. The structure and function of neurovascular unit manifest great significance in the central nervous system diseases. This paper discusses matrix metalloproteinase (MMP) impact on the stability of the neural vascular unit, by directly decomposing extracellular matrix, inducing the glial cell migration, activating angiogenesis, regulating function of blood spinal cord barrier, and put forward the MMP may be the key points in regulation of spinal cord neurovascular unit structure and function change to affect the outcome of chronic oppressive cervical spinal cord.
Cell Movement ; Humans ; Matrix Metalloproteinases ; physiology ; Nerve Compression Syndromes ; diagnosis ; enzymology ; Neurons ; cytology ; Prognosis ; Spinal Cord Injuries ; diagnosis ; enzymology

The matrix metalloproteinases (MMPs) play a key role in the normal physiology of connective tissue during development, morphogenesis, and wound healing. Dysregulation of their activity has been implicated in numerous diseases including encephalopathy and the process of bone loss. Thus, MMPs may play a role in the encephalopathy and post-transplantation bone disease by immunosuppressive drugs such as cyclosporine (CsA) and tacrolimus. Gelatin zymography of MMP-9 and MMP-2 was performed in the glioma cells and osteoblast after CsA or tacrolimus treatment. Glioma cells or rat osteoblast ROS17/2.8 cells were treated with CsA or tacrolimus to make final concentration from 2 to 250 µM. After incubation, gelatin zymography of MMP-9 and MMP-2 was performed. And the density for the MMP bands were measured using luminescent image analyzer system. Both MMP-9 and MMP-2 activities in the osteoblast cells were decreased depending on the concentration of CsA or tacrolimus. MMP-2 activity was increased after CsA or tacrolimus treatment in the glioma cells. However, MMP-9 activities were decreased after CsA or tacrolimus treatment in the glioma cells. These results indicate that dysregulation of MMPs in the osteoblast and in the glioma cells by immunosuppressive drugs may one of the contributing factors in post-transplantation bone disease and in the encephalopathy by tacrolimus or cyclosporine.
Animals ; Bone Diseases ; Connective Tissue ; Cyclosporine ; Gelatin ; Glioma* ; Matrix Metalloproteinases ; Morphogenesis ; Osteoblasts* ; Physiology ; Rats ; Tacrolimus ; Wound Healing

OBJECTIVETo investigate the effects of adenovirus-delivered angiopoietin-1 siRNA (Ad. Ang-1siRNA) on the expression of matrix metalloproteinase-2, 9 (MMP-2, 9) and tissue inhibitor of metallopro-teinase-1 (TIMP-1) in rats with acute lung injury (ALI) induced by phosgene (Psg).

METHODSWe first established a rat model of Psg-induced acute lung injury (ALI). The rats were randomly divided into 6 groups: air control group with exposure to air, air+adenovirus (air+Ad) group with caudal vein injection of 1×10(8) pfu/ml adenovirus 1 h after air exposure, air+Ad/Ang1 group with caudal vein injection of 1×10(8) pfu/ml Ad.Ang-1siRNA 1 h after air exposure, Psg group with exposure to 8.33 mg/L Psg (purity 100%, of the same volume as the inhaled air in the air control group) for 5 min, Psg+Ad group with caudal vein injection of 1×10(8) pfu/ml adenovirus 1 h after exposure to the same dose of Psg, and Psg+Ad/Ang1 group with caudal vein injection of 1×10(8) pfu/ml Ad.Ang-1siRNA 1 h after exposure to the same dose of Psg. Serum, bronchoalveolar lavage fluid (BALF), and lung tissue were collected 36 h after exposure. The protein expression of Ang-1, MMP-2, 9, and TIMP-1 in serum and BALF was determined by double-antibody sandwich ELISA. RT-PCR was used to determine the mRNA levels of Ang-1, MMP-2, 9, and TIMP-1 in lung tissue. The protein expression of MMP-2, 9 and TIMP-1 in lung tissue was determined by Western blot.

RESULTSA rat model of Psg-induced ALI was successfully established. The levels of MMP-2, 9 in serum, BALF, and lung tissue were significantly increased in the Psg group and Psg+Ad/Ang1 group as compared with the control group (P<0.01); no significant change was observed in serum TIMP-1 protein expression (P>0.05); interestingly, TIMP-1 protein expression in BALF and lung tissue was significantly increased (P<0.01). Compared with the Psg group, the Psg+Ad/Ang1 group showed a significant decrease in MMP-2, 9 expression in BALF, serum, and lung tissue (P<0.05), but no significant change in protein expression of TIMP-1 was discovered (P>0.05).

CONCLUSIONAd.Ang-1siRNA has a potential beneficial effect in rats with Psg-induced ALI through inhibition of MMP-2, 9 expression, but has no significant effect on the expression of TIMP-1.

Acute Lung Injury ; chemically induced ; metabolism ; Adenoviridae ; genetics ; Angiopoietin-1 ; physiology ; Animals ; Bronchoalveolar Lavage Fluid ; Chemical Warfare Agents ; toxicity ; Disease Models, Animal ; Lung ; metabolism ; Matrix Metalloproteinase 2 ; genetics ; Matrix Metalloproteinases ; metabolism ; Phosgene ; toxicity ; RNA, Messenger ; genetics ; RNA, Small Interfering ; Rats ; Tissue Inhibitor of Metalloproteinase-1 ; metabolism

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