OBJECTIVES: Osteoarthritis (OA) is one of the most common chronic degenerative diseases, with chondrocyte apoptosis and extracellular matrix (ECM) degradation as the major pathological changes. The mechanical stimulation can attenuate chondrocyte apoptosis and promote ECM synthesis, but the underlying molecular mechanisms remain unclear. This study aims to investigate the role of primary cilia (PC) in mediating the effects of mechanical stimulation on OA progression. METHODS: In vivo, conditional knockout mice lacking intraflagellar transport 88 (IFT88^flox/flox IFT88 knockout; i.e., primary cilia-deficient mice) were generated, with wild-type mice as controls. OA models were established via anterior cruciate ligament transection combined with destabilization of the medial meniscus, followed by treadmill exercise intervention. OA progression was evaluated by hematoxylin-eosin staining, safranin O-fast green staining, and immunohistochemistry; apoptosis was assessed by TUNEL staining; and limb function by rotarod testing. In vitro, primary articular chondrocytes were isolated from mice and transfected with lentiviral vectors to suppress IFT88 expression, thereby constructing a primary cilia-deficient cell model. Interleukin-1β (IL-1β) was used to induce an inflammatory environment, while cyclic tensile strain (CTS) was applied via a cell stretcher to mimic mechanical loading on chondrocytes. Immunofluorescence and Western blotting were used to detect the protein expression levels of type II collagen α1 chain (COL2A1), primary cilia, IFT88, and caspase-12; reverse transcription polymerase chain reaction was performed to assess COL2A1 mRNA levels; and flow cytometry was used to evaluate apoptosis. RESULTS: In vivo, treadmill exercise significantly reduced Osteoarthritis Research Society International (OARSI) scores and apoptotic cell rates, and improved balance ability in wild-type OA mice, whereas IFT88-deficient OA mice showed no significant improvement. In vitro, CTS inhibited IL-1β-induced ECM degradation and apoptosis in primary chondrocytes; however, this protective effect was abolished in cells with suppressed primary cilia expression. CONCLUSIONS Mechanical stimulation delays OA progression by mediating signal transduction through primary cilia, thereby inhibiting cartilage degeneration and chondrocyte apoptosis.
Animals ; Chondrocytes/cytology* ; Apoptosis/physiology* ; Mice ; Cilia/metabolism* ; Osteoarthritis/pathology* ; Extracellular Matrix/metabolism* ; Mice, Knockout ; Disease Progression ; Interleukin-1beta ; Male ; Cells, Cultured

Meniscus injuries are widespread and the available treatments do not offer enough healing potential. Here, we provide critical support for using pigs as a biological model for meniscal degeneration and the development of cutting-edge therapies in orthopedics. We present a single-cell transcriptome atlas of the meniscus, consisting of cell clusters corresponding to four major cell types: chondrocytes, endothelial cells, smooth muscle cells, and immune cells. Five distinct chondrocyte subclusters (CH0‒CH4) were annotated, of which only one was widespread in both the red and white zones, indicating a major difference in the cellular makeup of the zones. Subclusters distinct to the white zone appear responsible for cartilage-specific matrix deposition and protection against adverse microenvironmental factors, while those in the red zone exhibit characteristics of mesenchymal stem cells and are more likely to proliferate and migrate. Additionally, they induce remodeling actions in other chondrocyte subclusters and promote the proliferation and maturation of endothelial cells, inducing healing and vascularization processes. Considering that they have substantial remodeling capabilities, these subclusters should be of great interest for tissue engineering studies. We also show that the cellular makeup of the pig meniscus is comparable to that of humans, which supports the use of pigs as a model in orthopedic therapy development.
Animals ; Swine ; Chondrocytes/physiology* ; Single-Cell Analysis ; Meniscus/blood supply* ; Endothelial Cells/cytology* ; Transcriptome ; Mesenchymal Stem Cells/cytology* ; Neovascularization, Physiologic ; Cell Proliferation

OBJECTIVES: To assess the therapeutic effect of aucubin in mice with knee osteoarthritis (KOA) and investigate the underlying mechanism. METHODS: Sixty C57BL/6J mice were randomized equally into sham operation group, KOA model group, glucosamine (positive control) treatment group, and low-, medium-, and high-dose aucubin treatment groups (2, 4, and 8 mg/kg, respectively). KOA mouse models were established by transection of the anterior cruciate ligament (ACL), and the treatment was initiated on day 1 postoperatively and administered weekly for 8 weeks. Safranin O-fast green staining, immunohistochemistry, and microCT were used to evaluate the changes in cartilage pathology, inflammatory protein expression, and subchondral bone volume fraction (BV/TV). The expression levesl of COL2, SOX9, p-P65, IL-1β and MMP13 proteins in the cartilage tissues were detected using Western blotting. In a chondrocyte model with IL-1β treatment for mimicking KOA, the effect of aucubin on chondrogenic differentiation was observed with Alcian blue and Safranin O staining, and cellular COL2, SOX9 and TNF‑α mRNA expressions were detected with RT-qPCR. RESULTS: Compared with those in the model group, the mouse models receiving aucubin treatment showed significantly upregulated COL2 and SOX9 protein levels and downregulated p-P65, IL-1β and MMP13 expressions in the cartilage tissues. In the IL-1β-induced chondrocyte model, aucubin treatment significantly upregulated the mRNA expressions of SOX9 and COL2 but lowered the mRNA expression of TNF-α. Alcian blue and Safranin O staining confirmed that aucubin promoted the synthesis of cartilage extracellular matrix and enhanced chondrogenic differentiation of the cells. CONCLUSIONS Aucubin can effectively alleviate KOA in mice by inhibiting NF‑κB-mediated cartilage inflammation, promoting cartilage matrix synthesis, and improving subchondral bone microstructure.
Animals ; Mice, Inbred C57BL ; Mice ; Osteoarthritis, Knee/drug therapy* ; Signal Transduction/drug effects* ; NF-kappa B/metabolism* ; Iridoid Glucosides/therapeutic use* ; SOX9 Transcription Factor/metabolism* ; Chondrocytes/drug effects* ; Male ; Interleukin-1beta/metabolism* ; Matrix Metalloproteinase 13/metabolism* ; Collagen Type II/metabolism* ; Disease Models, Animal

OBJECTIVE: To analyze the influences of dihydromyricetin on the proliferation and apoptosis of chondrocytes in osteoarthritis induced by hydrogen peroxide (H₂O₂) through reactive oxygen species (ROS)/p38 mitogen activated protein kinase (p38-MAPK) pathway. METHODS: Five C57BL/6J mice were euthanized by cervical dislocation after anesthesia. Chondrocytes were extracted and cultured.After passage, the chondrocytes were divided into control group, H2O2 group (0.8 μmol·L^-1 H₂O₂), dihydromyricetin low concentration group (0.8 μmol·L^-1 H₂O₂+20 μmol·L^-1 dihydromyricetin), dihydromyricetin high concentration group (0.8 μmol·L^-1 H₂O₂+80 μmol·L^-1 dihydromyricetin), and ROS inhibitor N-acetylcysteine (NAC) group (0.8 μmol·L^-1 H₂O₂+5 mmol·L^-1 NAC). The activity of chondrocytes was measured by methyl thiazolyl tetrazolium (MTT) assay. The apoptosis rate of chondrocytes was measured by Hoechst 33342 method. The level of ROS in chondrocytes was measured by 2, 7-dichlorofluorescein diacetate (DCFH-DA) fluorescence probe.The level of Type II collagen α1 (Col2α1) mRNA was measured by qRT-PCR.And the expression of Col2α1, p-p38-MAPK/p38-MAPK, B cell lymphoma gene-2 (Bcl-2) and Bcl-2 associated X protein (Bax) proteins was detected by Western blot. RESULTS: The chondrocytes showed swirling fibrous mass, and the expression of COL2α was positive. Compared with the control group, the chondrocyte viability, apoptosis rate, ROS fluorescence intensity, p-p38-MAPK/p38-MAPK, and the expression of Bax protein in H2O22 group increased, the level of Col2α1 mRNA, and the expression of Col2α1 and Bcl-2 proteins decreased (P<0.05). Compared with H₂O₂ group, the chondrocyte viability, apoptosis rate, ROS fluorescence intensity, p-p38-MAPK/p38-MAPK, and the expression of Bax protein in dihydromyricetin low concentration group, dihydromyricetin high concentration group, and NAC group decreased, the level of Col2α1 mRNA, and the expression of Col2α1 and Bcl-2 proteins increased (P<0.05). CONCLUSION Dihydromyricetin may inhibit chondrocyte apoptosis, inflammatory reaction and oxidative stress by inhibiting ROS/p38-MAPK pathway. Dihydromyricetin may be a potential drug for treating osteoarthritis.
Animals ; Chondrocytes/metabolism* ; Apoptosis/drug effects* ; Hydrogen Peroxide/toxicity* ; Osteoarthritis/physiopathology* ; Mice, Inbred C57BL ; Reactive Oxygen Species/metabolism* ; Mice ; Flavonols/pharmacology* ; p38 Mitogen-Activated Protein Kinases/genetics* ; Cell Proliferation/drug effects* ; Male ; Signal Transduction/drug effects* ; MAP Kinase Signaling System/drug effects* ; Cells, Cultured

With the deepening understanding of the pathogenesis of osteoarthritis (OA), therapeutic strategies targeting oxidative stress in chondrocytes have gradually become a research hotspot. This article summarizes the important role of oxidative stress in the development of OA, pointing out that it is closely related to chondrocyte senescence, inflammatory cascade reaction, and cartilage matrix degradation. Given the central role of oxidative stress in the pathological process of OA, inhibiting oxidative stress and the generation of reactive oxygen species (ROS) is considered the key to alleviating chondrocyte damage and senescence, and preventing the progression of OA. Although some progress has been made in current OA research, there are still many challenges, such as the in-depth understanding of the etiology of OA and the limited selection of therapeutic drugs. Future research will focus on a more comprehensive understanding of the mechanism of oxidative stress in OA, exploring new biomarkers and therapeutic targets, and developing new drugs or treatment methods targeting oxidative stress pathways. These efforts are expected to bring more effective treatment options to OA patients, thereby improving their quality of life and prognosis.
Humans ; Oxidative Stress ; Osteoarthritis/pathology* ; Chondrocytes/pathology* ; Animals ; Reactive Oxygen Species/metabolism*

Osteoarthritis (OA) is the most common degenerative joint disease. Its pathological process is related to inflammatory response, chondrocyte apoptosis, and cartilage degeneration. Hippo-yes-associate protein(YAP) signaling pathway plays an important role in mediating organ size and tissue homeostasis. In recent years, the key effector protein YAP in the Hippo-YAP pathway has become a research hotspot in osteoarthritis. This article introduces the activation process of Hippo-YAP signaling pathway and the biological role of YAP. It reviews the progress of YAP in regulating osteoarthritis by influencing the proliferation and differentiation of mesenchymal stem cells and the proliferation, differentiation, and apoptosis of articular chondrocytes. It analyzed the problems encountered in YAP research in OA, introduces the research potential of YAP in other orthopedic diseases, and provides new ideas for subsequent research in Osteoarthritis.
Osteoarthritis/metabolism* ; Humans ; Signal Transduction ; Protein Serine-Threonine Kinases/physiology* ; Hippo Signaling Pathway ; YAP-Signaling Proteins ; Adaptor Proteins, Signal Transducing/physiology* ; Animals ; Transcription Factors ; Chondrocytes/cytology* ; Cell Cycle Proteins

Objective To explore the effect of rehmanniae radix extract(RRE)on chondrocyte apoptosis in the rabbit model of knee osteoarthritis(KOA)by regulating the miR-485-5p/heat shock protein 90 beta family member 1(Hsp90b1)axis.Methods New Zealand rabbits were randomly assigned into control,KOA,low-dose RRE,medium-dose RRE,high-dose RRE,celecoxib,high-dose RRE+antagonist control,and high-dose RRE+miR-485-5p antagonist groups,with 12 rabbits in each group.Rabbits in other groups except the control group were modeled for KOA with the improved Hulth method.After modeling for 8 weeks,the rabbits were administrated with corresponding agents for 4 weeks.The changes in the activity rating of rabbits were recorded.ELISA was employed to measure the levels of tumor necrosis factor-α(TNF-α)and interleukin(IL)-6 in the serum.Safranine O-fast green staining was conducted to reveal the pathological changes in the cartilage tissue and Mankin scoring was performed.TUNEL was employed to detect chondrocyte apoptosis.Real-time fluorescence quantitative PCR was performed to determine the expression of miR-485-5p in the cartilage tissue.Western blot was employed to determine the protein levels of Hsp90b1,cleaved cysteinyl aspartate-specific proteinase-3(Caspase-3),and Bcl2-associated-X(Bax)in the cartilage tissue.The dual-luciferase reporter assay was employed to examine the relationship between miR-485-5p and Hsp90b1.Results Compared with the control group,the KOA group showed down-regulated expression of miR-485-5p,elevated levels of TNF-α and IL-6 in the serum,cartilage erosion and losses,and increases in activity rating,Mankin score,chondrocyte apoptosis rate,and protein levels of Hsp90b1,cleaved Caspase-3,and Bax(all P<0.001).Compared with the KOA group,RRE at low,medium,and high doses,and celecoxib up-regulated the expression of miR-485-5p,lowered the levels of TNF-α and IL-6 in the serum,alleviated the pathological damage to the cartilage tissue,and decreased the activity rating,Mankin score,chondrocyte apoptosis rate,and protein levels of Hsp90b1,cleaved Caspase-3,and Bax(all P<0.05).Compared with the high-dose RRE group and the high-dose RRE+antagonist control group,high-dose RRE+miR-485-5p antagonist down-regulated the expression of miR-485-5p,elevated the levels of TNF-α and IL-6 in the serum,exacerbated the pathological damage to the cartilage tissue,and increased the activity rating,Mankin score,chondrocyte apoptosis rate,and protein levels of Hsp90b1,cleaved Caspase-3,and Bax(all P<0.05).The results indicated that there was a targeted regulatory relationship between miR-485-5p and Hsp90b1.Conclusion RRE may inhibit the expression of Hsp90b1 by up-regulating miR-485-5p,thereby inhibiting chondrocyte apoptosis in the rabbit model of KOA.
Animals ; Rabbits ; Apoptosis/drug effects* ; Chondrocytes/pathology* ; Osteoarthritis, Knee/drug therapy* ; MicroRNAs/metabolism* ; Rehmannia/chemistry* ; Disease Models, Animal ; Tumor Necrosis Factor-alpha/blood* ; Plant Extracts/pharmacology* ; Interleukin-6/blood* ; HSP90 Heat-Shock Proteins/metabolism* ; Male ; Drugs, Chinese Herbal/pharmacology*

This study aims to investigate the action mechanism of Shenzhuo Decoction(SZT, i.e., Ganjiang Lingzhu Decoction) in treating knee osteoarthritis(KOA). Network pharmacology was used to analyze the key targets of SZT in the treatment of KOA. At the cellular experimental level, primary chondrocytes extracted from rats were used for in vitro validation. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling(TUNEL) staining was employed to detect chondrocyte apoptosis in the knee joint. Western blot was performed to analyze the expression of the anti-apoptotic factor(Bcl2), the apoptosis marker gene Bax, and key proteins in the phosphoinositide 3-kinase(PI3K)-protein kinase B(Akt) signaling pathway. In animal experiments, 60 7-week-old male SD rats were used to establish a KOA model and randomly divided into a control group, a KOA model group, high-, medium-, and low-dose SZT groups, and a celecoxib group, with 10 rats in each group. Micro-CT was used to observe changes in bone mineral density and osteophytes at the articular cartilage surface. Hematoxylin-eosin(HE) staining and safranin O-fast green(SFO) staining were used to observe pathological changes in cartilage tissue. Immunohistochemistry was used to detect the expression of inflammatory factor matrix metalloproteinase 13(MMP13) and cartilage marker collagen Ⅱ. Quantitative reverse transcription-polymerase chain reaction(qRT-PCR) was used to detect the expression of chondrocyte marker SRY-box transcription factor 9(SOX9) and inflammatory markers matrix metalloproteinase 9(MMP9), interleukin-6(IL-6), interleukin-1β(IL-1β), and tumor necrosis factor-α(TNF-α). Cell experiments revealed that SZT effectively improved KOA, and the results of micro-CT and HE and SFO staining showed that compared with the control group, the model group had obvious formation of osteophytes on the joint surface, which became rough, with significant decreases in the trabecular bone volume fraction(BV/TV), trabecular number(Tb.N), and trabecular thickness(Tb.Th) and a significant increase in trabecular spacing(Tb.Sp). The SZT groups had few osteophytes and a smoother joint surface than the model group. Additionally, BV/TV, Tb.N, and Tb.Th were significantly increased, while Tb.Sp was gradually decreased. A SZT-component-KOA target network was constructed to locate the core targets in KOA treatment, which was further validated through in vivo and in vitro animal experiments. The immunohistochemistry results of the pathological section of rat joint tissue showed that compared with the control group, the model group had a significant increase in MMP13 and a decrease in collagen Ⅱ, while SZT could inhibit inflammation and strengthen the protection of collagen Ⅱ in articular cartilage. The qRT-PCR results showed that SZT could significantly inhibit the mRNA expression of IL-6, IL-1β, TNF-α, and MMP9 and upregulate the mRNA level of SOX9. The TUNEL detection results showed that in the lipopolysaccharide(LPS)-induced KOA model group, chondrocyte apoptosis was significantly increased, and the fluorescence intensity was significantly enhanced. SZT, however, significantly reduced the trend of chondrocyte apoptosis and decreased the fluorescence intensity. The Western blot results showed that SZT could effectively inhibit the phosphorylation level of proteins in the PI3K-Akt pathway, reduce the expression of Bax, increase the expression of Bcl2, and inhibit the degradation of SOX9. In conclusion, SZT may alleviate the degenerative damage of KOA by inhibiting the phosphorylated expression of key proteins in the PI3K-Akt signaling pathway, reducing the release of inflammatory factors, and inhibiting chondrocyte apoptosis.
Animals ; Chondrocytes/metabolism* ; Drugs, Chinese Herbal/administration & dosage* ; Male ; Osteoarthritis, Knee/physiopathology* ; Rats, Sprague-Dawley ; Rats ; Apoptosis/drug effects* ; Signal Transduction/drug effects* ; Phosphatidylinositol 3-Kinases/metabolism* ; Proto-Oncogene Proteins c-akt/immunology* ; Humans

From the perspective of competitive endogenous RNA(ceRNA) constructed by metastasy-associated lung adenocarcinoma transcript 1(Malat1) and microRNA 16-5p(miR-16-5p), the improvement mechanism of Tonggu Xiaotong Capsules(TGXTC) on the imbalance and disorder of "cholesterol-iron" metabolism in chondrocytes of osteoarthritis(OA) was explored. In vivo experiments, 60 8-week-old C57BL/6 mice were acclimatized and fed for 1 week and then randomly divided into two groups: blank group(12 mice) and modeling group(48 mice). The animals in modeling group were anesthetized by 5% isoflurane inhalation, which was followed by the construction of OA model. They were then randomly divided into model group, TGXTC group, Malat1 overexpression group, and TGXTC+Malat1 overexpression(TGXTC+Malat1-OE) group, with 12 mice in each group. The structural changes of mouse cartilage tissues were observed by Masson staining after the intervention in each group. RT-PCR was employed to detect the mRNA levels of Malat1 and miR-16-5p in cartilage tissues. Western blot was used to analyze the protein expression of ATP-binding cassette transporter A1(ABCA1), sterol regulatory element-binding protein(SREBP), cytochrome P450 family 7 subfamily B member 1(CYP7B1), CCAAT/enhancer-binding protein homologous protein(CHOP), acyl-CoA synthetase long-chain family member 4(ACSL4), and glutathione peroxidase 4(GPX4) in cartilage tissues. In vitro experiments, mouse chondrocytes were induced by thapsigargin(TG), and the combination of Malat1 and miR-16-5p was detected by double luciferase assay. The fluorescence intensity of Malat1 in chondrocytes was determined by fluorescence in situ hybridization. The miR-16-5p inhibitory chondrocyte model was constructed. RT-PCR was used to analyze the levels of Malat1 and miR-16-5p in chondrocytes under the inhibition of miR-16-5p. Western blot was adopted to analyze the regulation of TG-induced chondrocyte proteins ABCA1, SREBP, CYP7B1, CHOP, ACSL4, and GPX4 by TGXTC under the inhibition of miR-16-5p. The results of in vivo experiments showed that,(1) compared with model group, TGXTC group exhibited a relatively complete cartilage layer structure. Compared with Malat1-OE group, TGXTC+Malat1-OE group showed alleviated cartilage surface damage.(2) Compared with model group, TGXTC group had a significantly decreased Malat1 mRNA level and an increased miR-16-5p mRNA level in mouse cartilage tissues(P<0.01).(3) Compared with the model group, the protein levels of ABCA1 and GPX4 in the cartilage tissue of mice in the TGXTC group increased, while the protein levels of SREBP, CYP7B1, CHOP and ACSL4 decreased(P<0.01). The results of in vitro experiments show that,(1) dual-luciferase was used to evaluate that miR-16-5p has a targeting effect on the Malat1 gene.(2)Compared with TG+miR-16-5p inhibition group, TG+miR-16-5p inhibition+TGXTC group had an increased mRNA level of miR-16-5p and an decreased mRNA level of Malat1(P<0.01).(3) Compared with TG+miR-16-5p inhibition group, TG+miR-16-5p inhibition+TGXTC group exhibited increased expression of ABCA1 and GPX4 proteins and decreased expression of SREBP, CYP7B1, CHOP, and ACSL4 proteins(P<0.01). The reasults showed that TGXTC can regulate the ceRNA of Malat1 and miR-16-5p to alleviate the "cholesterol-iron" metabolism disorder of osteoarthritis chondrocytes.
Animals ; MicroRNAs/metabolism* ; RNA, Long Noncoding/metabolism* ; Chondrocytes/drug effects* ; Drugs, Chinese Herbal/pharmacology* ; Mice, Inbred C57BL ; Mice ; Osteoarthritis/drug therapy* ; Iron/metabolism* ; Male ; Cholesterol/metabolism* ; Humans ; Capsules ; RNA, Competitive Endogenous

From the perspective of circular RNA forkhead box protein O3(circFOXO3) regulating glycolysis in osteoarthritis(OA) chondrocytes, this study investigated the mechanism by which Tougu Xiaotong Capsules(TGXTC) alleviated OA degeneration. In in vivo experiments, after randomized grouping and relevant interventions, morphological staining was used to observe structural changes in cartilage tissue. The mRNA level of circFOXO3 in cartilage tissue was detected by real-time quantitative PCR(RT-qPCR). Western blot analysis was used to detect changes in the expression of glucose transporter 1(GLUT1), hexokinase 2(HK2), pyruvate kinase M2(PKM2), lactate dehydrogenase A(LDHA), and matrix metalloproteinase 13(MMP13). In in vitro experiments, fluorescence in situ hybridization(FISH) was used to detect circFOXO3 expression in chondrocytes from each group. A lentiviral vector was used to construct circFOXO3-silenced(sh-circFOXO3) chondrocytes. RT-qPCR was used to analyze the changes in circFOXO3 levels after silencing, and Western blot was used to assess the regulatory effects of TGXTC on GLUT1, HK2, PKM2, LDHA, and MMP13 proteins in interleukin-1β(IL-1β)-induced chondrocytes under sh-circFOXO3 conditions. Masson staining and alcian blue staining results showed that the cartilage layer structure in the TGXTC and positive drug groups was improved compared with that in the model group. The mRNA level of circFOXO3 was significantly upregulated in both the TGXTC and positive drug groups, while the expression of the above-mentioned proteins was significantly reduced. FISH results showed that TGXTC upregulated the fluorescence intensity of circFOXO3 in IL-1β-induced chondrocytes. In the circFOXO3 silencing experiment, compared with the IL-1β group, circFOXO3 levels in the IL-1β + sh-circFOXO3 group were significantly decreased. Compared with the IL-1β + TGXTC group, circFOXO3 levels were significantly reduced in the IL-1β + sh-circFOXO3 + TGXTC group. Western blot results indicated that the elevated levels of GLUT1, HK2, PKM2, LDHA, and MMP13 proteins in chondrocytes of the IL-1β group were significantly inhibited by TGXTC intervention. However, this regulatory effect was attenuated after circFOXO3 silencing. In conclusion, TGXTC alleviate glycolytic metabolism disorder in OA chondrocytes and delay OA degeneration by regulating circFOXO3.
Chondrocytes/metabolism* ; Animals ; Drugs, Chinese Herbal/administration & dosage* ; RNA, Circular/metabolism* ; Osteoarthritis/genetics* ; Glycolysis/drug effects* ; Humans ; Forkhead Box Protein O3/metabolism* ; Male ; Capsules ; Matrix Metalloproteinase 13/genetics*