Basic Research Open Access
Copyright ©The Author(s) 2005. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Aug 28, 2005; 11(32): 4953-4956
Published online Aug 28, 2005. doi: 10.3748/wjg.v11.i32.4953
Effect of Danshao Huaxian capsule on expression of matrix metalloproteinase-1 and tissue inhibitor of metalloproteinase-1 in fibrotic liver of rats
Qin Yang, Ru-Jia Xie, Bing Han, Department of Pathophysiology, Guiyang Medical College, Guiyang 550004, Guizhou Province, China
Xiao-Xia Geng, Ming-Liang Cheng, Department of Infectious Diseases, Affiliated Hospital of Guiyang Medical College, Guiyang 550004, Guizhou Province, China
Xin-Hua Luo, Department of Infectious Diseases, People’s Hospital of Guizhou Province, Guiyang 550004, Guizhou Province, China
Author contributions: All authors contributed equally to the work.
Supported by the Foundation of Traditional Chinese Medicine Modernization Project of Guizhou Province, No. 200409
Correspondence to: Dr. Ming-Liang Cheng, Department of Infectious Diseases, Affiliated Hospital of Guiyang Medical College, 4 Beijing road, Guiyang 550004, Guizhou Province, China. chengml@21.cn.com
Telephone: +86-851-6855119-3193
Received: October 30, 2004
Revised: November 16, 2004
Accepted: November 19, 2004
Published online: August 28, 2005

Abstract

AIM: To investigate the effects of Danshao Huaxian (DSHX) capsules, a preparation of traditional Chinese medicine, on the expression of matrix metalloproteinase-1 (MMP-1), and tissue inhibitor of metalloproteinase-1 (TIMP-1) in the fibrous livers of rats.

METHODS: Eighty male Wistar rats were randomly divided into normal control group (group A), CCl4-induced hepatic fibrosis group (group B), non-DSHX-treated group (group C), low dose-treated group (group D), and high dose-treated group (group E). Fibrous liver models in rats were induced by subcutaneous injection of CCl4, oral administration of alcohol and high-lipid/low-protein diet for 8 wk. After the models were established, the rats in groups D and E were orally given a low dose (0.5 g/kg) and a high dose (1.0 g/kg) of DSHX daily for 8 wk, respectively. Then, the liver indexes, serum hyaluronic acid (HA) and alanine aminotransferase (ALT) were examined. The degree of hepatic fibrosis was evaluated by optical microscopy. Hydroxyproline (Hyp) in the urine was determined, and the expression of MMP-1 and TIMP-1 was detected by immunohistochemical techniques.

RESULTS: In groups D and E, the liver indexes, levels of serum HA and ALT reduced and development of hepatic fibrosis weakened significantly. The urinary Hyp and expression of MMP-1 in the liver tissues elevated, but the expression of TIMP-1 decreased obviously, as compared to groups B and C.

CONCLUSION: DSHX enhances the expression of MMP-1 but decreases that of TIMP-1 in liver tissues of CCl4-induced hepatic fibrotic rats, which may result in its elevated activity that contributes to fighting against hepatic fibrosis.

Key Words: Danshao Huaxian capsule, Hepatic fibrosis, MMP-1, TIMP-1, Collagen



INTRODUCTION

Hepatic fibrosis is a common result of any chronic injury to the liver. It is characterized by excessive deposition of extracellular matrix (ECM), especially collagens I and III[1-4]. Matrix metalloproteinase (MMP), is a member of zinc-dependent endopeptidase family, that degrades various components of ECM. In liver tissues, 8 members of MMP have been discovered[5]. One of them is matrix metallop-roteinase-1 (MMP-1) with its specific inhibitor, tissue inhibitor of metalloproteinase-1 (TIMP-1) closely correlated with liver fibrosis due to the accumulation and degradation balance of collagens I and III[6-8]. In this study, we examined the therapeutic effect of Danshao Huaxian (DSHX) capsule on CCl4-induced hepatic fibrosis in rats and explored its mechanism.

MATERIALS AND METHODS
Experimental animals

Eighty male Wistar rats weighing 180-220 g were provided by the Experimental Animal Center of Guiyang Medical College. The rats were randomly divided into five groups: normal control group (group A), CCl4-induced hepatic fibrosis group (group B), non-DSHX-treated group (group C), low dose DSHX-treated group (group D), and high dose DSHX-treated group (group E). Each group consisted of 16 rats.

Chemicals and reagents

DSHX capsule containing five Chinese herbal medicines (Tetrandrine, Radix Salviae Miltiorrhizae, Radix Paeoniae Rubra, Astragalus Membranaceus and Ginkgleaf) was supplied by Guiyang Pharmaceutical Company. Carbon tetrachloride (CCl4) was obtained from Chongqing Inorganic Chemistry Factory and cholesterol was from Beijing Chemical Reagent Company. Immunohistochemical kits for MMP-1 and TIMP-1, hyaluronic acid (HA) and hydroxyproline (Hyp) kits were purchased from Wuhan Boster Biological Engineering Ltd Co., Beijing Northern Biological Technical Research Institute and Nanjing Jiancheng Biological Engineering Research Institute, respectively.

Instruments

Automatic biochemical analytic instrument (Hitachi 7170A) and Olympus BX41 Microimage Collecting System were employed in the study.

CCl4-induced liver fibrosis and sample collection

Liver fibrosis was induced in four groups by a complex method[9]. The rats in groups B, C, D, and E received subcutaneous injections of 40% CCl4 solution (a mixture of pure CCl4 and peanut oil) and 0.3 mL/100 g, twice a week for 8 wk (the first dose was pure CCl4 0.5 mL/100 g). Meanwhile, they were fed with high-lipid/low-protein diet (79.5% corn farina, 20% fat, and 0.5% cholesterol) daily, and orally supplemented with 30% alcohol every other day. Rats in group A were fed only with normal diet. After liver fibrosis was produced, the rats in group B (by this time, only 12 rats survived) were killed and their blood and livers were collected. The wet livers were weighed and liver samples were fixed in 40 g/L formaldehyde. The serum was centrifuged at 1 500 r/min for 5 min and stored at -80 °C. DSHX capsules were then given to the rats in group D (0.5 g/kg, p.o., daily) and group E (1.0 g/kg, p.o., daily) for 8 wk. The rats in group C were given normal saline instead of DSHX. At the end of the experiment (by this time, the rat survivors in group A and groups C-E were 16, 10, 10, and 10, respectively), all the rats were killed, the liver and serum samples were handled in the same way as mentioned above.

Liver index calculation

Liver index was calculated according to the formula (liver weight/body weight)×100%.

Measurements of serum HA and ALT

Concentrations of serum HA and alanine aminotransferase (ALT) were measured by radioimmunoassay or automatic biochemical analytic instrument (Hitachi 7170A).

Histopathological examination

An equal portion of liver from each rat (1 cm±1 cm±0.5 cm) was fixed in 40 g/L formaldehyde for 48 h, embedded in paraffin, and sectioned with a microtome. The 5-μm-thick sections were stained with hematoxylin and eosin for general histopathology examination. Van-Gieson staining was performed for evaluating the severity of liver fibrosis. Liver fibrosis was classified as previously described[10].

Urinary Hyp determination

The 24 h urine of the rats in each experimental group was collected for determination of urinary Hyp in the 8th wk and at the end of the experiment, respectively.

Expression of MMP-1 and TIMP-1

The expressions of MMP-1 and TIMP-1 were detected by the streptavidin-biotin complex (SABC) immunohistochemical technique strictly following the directions offered. PBS was used as the negative control to produce MMP-1 and TIMP-1 polyclonal rabbit IgG. Finally, the number of positive cells per field of vision at 400× magnification was counted.

Statistical analysis

Quantitative data were expressed as mean±SD and subjected to one-way analysis of variance, followed by t test for multiple comparisons. Ordinal data were analyzed by Radit analysis. P<0.05 was considered statistically significant.

RESULTS
Effect of DSHX on liver index, concentration of serum HA and ALT in rats

As shown in Table 1, compared to group A, the liver index and concentrations of serum HA and ALT of rats in group B and group C increased greatly (P<0.05). After 8 wk of treatment with DSHX, the liver index and concentration of serum HA and ALT in groups D and E, reduced obviously compared to those in groups B and C (P<0.05).

Table 1 Liver index, serum HA, and ALT in rats of each group (mean±SD).
GroupnLiver index (relative liver weight)HA (ng/mL)ALT (U/L)
A160.0249±0.0027192.52±41.9732.40±2.30
B120.0423±0.0044b316.17±78.48a174.50±6.02b
C100.0295±0.0019bd300.86±72.73a104.75±6.54bd
D100.0268±0.0028de224.92±36.62ce96.13±4.94de
E100.0267±0.0017df200.78±31.71ce93.13±5.79df
Effect of DSHX on degree of hepatic fibrosis

After HE and V-G staining, hepatocytes of the normal control rats were arrayed radially along the central vein and there were no collagen fibers. The lobular structure of the liver was destroyed and the hepatic cords were disordered in the rats of group B. Also, the fibrous connective tissues containing numerous inflammatory cells regenerated in the portal area. Meanwhile, collagen fibers expanded into the hepatic parenchyma and there appeared fibrous septa surrounding and separating the normal lobules. The degree of hepatic fibrosis in this group was significantly serious compared to that in group A (P<0.01). The hepatic fibrosis in group C was alleviated and the fibrous septa were thinner than those in group B. Except for the obvious expansion of collagen fibers, pseudo lobules were also found in some severe samples from group C. The lobular structure in groups D and E was ameliorated significantly, and regeneration of fibrous connective tissues and septa reduced as compared to that in groups B and C. The degree of the hepatic fibrosis in each group is shown in Table 2.

Table 2 Degree of hepatic fibrosis in rats of each group.
GroupnDegree of hepatic fibrosis
0IIIIIIIVVAverage
A1616000000
B120001744.25d
C100143202.60df
D101351001.60af
E101621001.30bf
Effect of DSHX on urinary excretion of Hyp

Urinary Hyp is an useful index to evaluate the degradation of hepatic collagen. Compared to group A, the Hyp excretion increased in groups B and C. After being treated with DSHX, Hyp in the urine of groups D and E was more than that in groups B and C, suggesting that DSHX capsule could facilitate degradation of collagen (Table 3).

Table 3 Urinary excretion of Hyp (μg/24 h) in rats of each group (mean±SD).
GroupnUrinary excretion of Hyp
A1647.80±5.76
B1262.00±6.40b
C10182.44±30.83b
D10242.76±49.76d
E10541.09±73.39df
Effect of DSHX on expression of MMP-1 and TIMP-1

Immunohistochemical (SABC) study showed that there were only a small number of cells with positive light yellow staining of MMP-1 and TIMP-1 in the normal livers. MMP-1 was observed only in some hepatocytes and stromal cells, whereas TIMP-1 was mainly distributed in vascular endothelial cells and some fibroblasts in the portal area. In the livers of groups B, C, D, and E, the cells with MMP-1 and TIMP-1 positive staining were detected in the fibrous septa and stained dark yellow. The expression of MMP-1 and TIMP-1 in group B was higher than that in group A (P<0.01). Compared to groups B and C, the expression of MMP-1 in groups D and E increased significantly, whereas that of TIMP-1 decreased sharply. The results are shown in Table 4.

Table 4 Percentage of expression of MMP-1 and TIMP-1 in each group (mean±SD).
GroupnMMP-1 (%)TIMP-1 (%)
A160.595±0.871.08±0.68
B125.956±1.85f9.04±1.60f
C105.104±2.20f6.46±1.77bf
D108.271±3.29ad5.07±0.69bc
E108.518±1.88ad4.32±0.63bd
DISCUSSION

DSHX capsule is a mixed preparation, composed of five traditional Chinese herbal medicines. We previously reported that DSHX is effective in prevention of hepatic fibrosis[11]. In this study, we found that after DSHX treatment of rats with liver fibrosis for 8 wk, the relative liver weight and concentration of serum HA and ALT significantly reduced and liver fibrosis was alleviated, suggesting that DSHX possesses a therapeutic effect on CCl4-induced hepatic fibrosis in rats by attenuating liver inflammation, preventing necrosis of hepatocytes and promoting their generation.

Hepatic fibrosis is a common consequence of enhanced ECM synthesis and weakened breakdown of proteins in the connective tissue, which lead to increased deposition of ECM in the extracellular matrix. The main component of ECM in normal liver is collagen, which is divided into types I, III-VI. Except for these collagen fibers, there are many other non-collagen components, including fibronectin, laminin, tenascin, and entactin[12]. In fibrous liver, overaccumulated ECM is mainly interstitial collagens (types I and III). Activated hepatic stellate cells (HSCs) are the main source of ECM[13-17] during liver fibrosis. HSCs in the space of Disse are in a quiescent form without fibrogenic activity, in part because they are in contact with a complex ECM composed of collagen type IV, laminin, and proteogl-ycans[18]. When separated from these factors, they are activated into a pro-fibrogenic myofibroblastic phenotype. The expression of MMP-2 increases obviously after liver injury, which may result in excess degradation of type IV collagen and disorder of the microenvironment of the space of Disse, and then HSCs become activated. Meanwhile, Kupffer cells generate cytokines in response to liver injury, in which HSCs are activated and ECM is overexpressed. Normally, deposition of matrix components in liver is well controlled through constant remodeling by matrix-degrading enzymes. MMP is the most important among ECM-degrading enzymes. MMP, a zinc-dependent endopeptidase, can degrade specific components of ECM and its biological activity can be suppressed by TIMPs[19]. MMPs are released by a variety of cells (macrophages, neutrophils, endothelial cells, etc.) and participate in such physiological and pathological processes as ECM degradation, tissue remodeling, angiogenesis, and tumor invasion[20-22].

Till now, 26 members of the family of MMPs have been identified[22] and with the following characteristics[23-25]. (1) Structurally, there is a zinc atom at the active site; (2) they are often in an inactivated form, when produced; (3) their primary structures contain two highly conserved sequences, a N-terminal peptide domain and a catalytic domain; and (4) they can be inhibited by specific inhibitors known as TIMPs. The activities of MMPs are regulated at the transcriptional level, through zymogen activation and suppression by a family of inhibitory proteins, TIMPs. Four members of the TIMP family have been identified so far, including TIMPs 1-4, which are named in the order of their discovery. Their sequences possess a highly conserved secondary structure interacting with proteins via six conserved disulfide bonds. It seems that there are two domains in the TIMP molecule, a N-terminal domain that is endowed with inhibition of metalloproteinase and a C-terminal domain that may be important in protein location or combination with progelatinases[26]. TIMPs act widely and their most important action is to inhibit the activity of MMPs. TIMPs can interact with MMPs to inhibit their activities at 1:1 stoichiometry[27-29]. MMP-1, a member of the MMP family that specifically degrades native collagen types III and I, plays an important role in the accumulation and degradation balance of ECM. The level of MMP-1 increases transiently in the early stage of liver fibrosis, but becomes undetectable in the stage of cirrhosis[30]. In contrast, the level of TIMP-1, a specific tissue inhibitor of MMP-1, elevates consistently in the fibrosis process and reaches its peak in the stage of cirrhosis. Upregulation of TIMP-1 and downregulation of MMP-1 result in the inhibition of degradation of collagen types I and III, which leads to overexpression and deposition of ECM in the extracellular matrix.

In addition to inhibiting the degradation of matrix, TIMP-1 plays a significant role in regulation of the apoptosis of such cells such as B lymphocytes, breast epithelial cells and HSCs. TIMP-1 inhibits the apoptosis of HSCs, indicating another possible mechanism whereby it is implicated in the pathogenesis of liver fibrosis. In this study, we found that MMP-1 in the two groups treated with DSHX was overexpr-essed, whereas the expression of TIMP-1 reduced significantly. We conclude that DSHX can reverse the process of liver fibrosis by upregulating the gene expression and generation of MMP-1 and downregulating the TIMP-1 expression. These results may provide a therapeutic strategy to combat hepatic fibrosis by targeting MMP-1 and TIMP-1.

Footnotes

Co-first-authors: Qin Yang and Ming-Liang Cheng

Co-correspondents: Qin Yang

Science Editor Wang XL and Guo SY Language Editor Elsevier HK

References
1.  Iredale JP, Benyon RC, Pickering J, McCullen M, Northrop M, Pawley S, Hovell C, Arthur MJ. Mechanisms of spontaneous resolution of rat liver fibrosis. Hepatic stellate cell apoptosis and reduced hepatic expression of metalloproteinase inhibitors. J Clin Invest. 1998;102:538-549.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 785]  [Cited by in F6Publishing: 789]  [Article Influence: 30.3]  [Reference Citation Analysis (0)]
2.  Yang CQ, Wang JY, Guo JS, Liu JJ, Zhang C. Effects of the recombinant plasmid of rat interstitial collagenase on experimental liver fibrosis. Zhonghua Xiaohua Zazhi. 2000;20:297-300.  [PubMed]  [DOI]  [Cited in This Article: ]
3.  Yang CQ, Hu GL, Tan DM, Zhang Z. Effects of matrix metallo-proteinase-1 and antisense tissue inhibitor of metalloproteinase-1 recombinant plasmind on rat liver fibrosis. Zhonghua Chuanranbing Zazhi. 2000;18:29-32.  [PubMed]  [DOI]  [Cited in This Article: ]
4.  Yang CQ, Hu GL, Tan DM, Zhang Z. Relativity of expression of MMP-1,TIMP-1 and variability of type I, III collagen during experimental liver fibrosis. Linchuang Gandanbing Zazhi. 2000;16:222-224.  [PubMed]  [DOI]  [Cited in This Article: ]
5.  Huang YQ, Gao Y, Chen ZH, Wang Y, Fang SG, Yang JZ, Li CL. Relationship of imbalanced expression of interstitial collagenase and its inhibitors, metalloproteinase-1 gene, to liver fibrosis. Diyi Junyi Daxue Xuebao. 1999;19:208-210.  [PubMed]  [DOI]  [Cited in This Article: ]
6.  Zhang ZA, Shi SX, Lin JG, Huang YC. The expression of MMP-1 and TIMP-1 mRNA in patients with viral hepatitis gravis. Linchuang Neike Zazhi. 2002;19:258-260.  [PubMed]  [DOI]  [Cited in This Article: ]
7.  Gomez DE, De Lorenzo MS, Alonso DF, Andrade ZA. Expression of metalloproteinases (MMP-1, MMP-2, and MMP-9) and their inhibitors (TIMP-1 and TIMP-2) in schistosomal portal fibrosis. Am J Trop Med Hyg. 1999;61:9-13.  [PubMed]  [DOI]  [Cited in This Article: ]
8.  Meng EH, Zhao JM, Wang SS, Liu WX, Liu P, Zhou GD, Zhang TH. Expression of matrix metalloproteinases in liver tissues with nonalcoholic steatohepatitis. Shijie Huaren Xiaohua Zazhi. 2002;10:1257-1260.  [PubMed]  [DOI]  [Cited in This Article: ]
9.  Li CX, Li L, Lou J, Yang WX, Lei TW, Li YH, Liu J, Cheng ML, Huang LH. The protective effects of traditional Chinese medicine prescription, han-dan-gan-le, on CCl4-induced liver fibrosis in rats. Am J Chin Med. 1998;26:325-332.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 16]  [Cited by in F6Publishing: 19]  [Article Influence: 0.7]  [Reference Citation Analysis (0)]
10.  Cheng ML, Yang CQ. The basic study and clinical research on hepatic fibrosis. Beijing Renmin Weisheng Chubanshe 2002. 269-270.  [PubMed]  [DOI]  [Cited in This Article: ]
11.  Cheng ML, Lu YY, Wu J, Luo TY, Ding YS. Clinical Study on Reversing Hepatic Fibrosis with Handan Ganle Capsule. Chinese J Integrated Traditional Western Med. 2001;7:16-18.  [PubMed]  [DOI]  [Cited in This Article: ]
12.  Kossakowska AE, Edwards DR, Lee SS, Urbanski LS, Stabbler AL, Zhang CL, Phillips BW, Zhang Y, Urbanski SJ. Altered balance between matrix metalloproteinases and their inhibitors in experimental biliary fibrosis. Am J Pathol. 1998;153:1895-1902.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 140]  [Cited by in F6Publishing: 150]  [Article Influence: 5.8]  [Reference Citation Analysis (0)]
13.  Bennett RG, Kharbanda KK, Tuma DJ. Inhibition of markers of hepatic stellate cell activation by the hormone relaxin. Biochem Pharmacol. 2003;66:867-874.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 57]  [Cited by in F6Publishing: 60]  [Article Influence: 2.9]  [Reference Citation Analysis (0)]
14.  Lemos QT, Magalhães-Santos IF, Andrade ZA. Immunological basis of septal fibrosis of the liver in Capillaria hepatica-infected rats. Braz J Med Biol Res. 2003;36:1201-1207.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 10]  [Cited by in F6Publishing: 11]  [Article Influence: 0.5]  [Reference Citation Analysis (0)]
15.  Benyon RC, Arthur MJ. Extracellular matrix degradation and the role of hepatic stellate cells. Semin Liver Dis. 2001;21:373-384.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 358]  [Cited by in F6Publishing: 388]  [Article Influence: 16.9]  [Reference Citation Analysis (0)]
16.  Song LL, Luo HS, Yu BP. Effects of hepatocyte growth factor on fibrosis and hepatic expression of MMP-1 and TIMP-1. Shijie Huaren Xiaohua Zazhi. 2003;11:209-213.  [PubMed]  [DOI]  [Cited in This Article: ]
17.  Xu JW, Gong J, Feng XL, Chang XM, Luo JY, Dong L, Jia K, Xu GP. Effects of estradiol on type I, III collagens and TGFβ1 in hepatic fibrosis in rats. Shijie Huaren Xiaohua Zazhi. 2003;11:1185-1188.  [PubMed]  [DOI]  [Cited in This Article: ]
18.  Wu YJ, Zhai WR, Zhuang L, Zhang YE, Zhu HG. Expression of matrix metalloproteinase-2 and its tissue inhibitor in rat liver fibrosis model. Shanghai Yike Daxue Xuebao. 1999;26:261-264.  [PubMed]  [DOI]  [Cited in This Article: ]
19.  Li W, Cao L, Chen Z, Li W, Du Q, Chen G. Study on the effects of FCu-IUD and FICu-IUD on matrix metalloproteinases in human uterine flushing and endometrium. J Huazhong Univ Sci Technolog Med Sci. 2002;22:9-11, 16.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 2]  [Cited by in F6Publishing: 2]  [Article Influence: 0.1]  [Reference Citation Analysis (0)]
20.  Zhang J, Cao YJ, Liu WM, Zhao BS, Zeng GQ, Duan EK. Expression of matrix metalloproteinase-28 in human normal cytotrophoblast cells and a choriocarinoma cell line, JEG-3. Chinese Sci Bulletin. 2002;47:732-736.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 3]  [Cited by in F6Publishing: 3]  [Article Influence: 0.1]  [Reference Citation Analysis (0)]
21.  Lichtinghagen R, Bahr MJ, Wehmeier M, Michels D, Haberkorn CI, Arndt B, Flemming P, Manns MP, Boeker KH. Expression and coordinated regulation of matrix metalloproteinases in chronic hepatitis C and hepatitis C virus-induced liver cirrhosis. Clin Sci (Lond). 2003;105:373-382.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 61]  [Cited by in F6Publishing: 64]  [Article Influence: 3.0]  [Reference Citation Analysis (0)]
22.  Zhao H, Cai G, Du J, Xia Z, Wang L, Zhu T. Expression of matrix metalloproteinase-9 mRNA in osteoporotic bone tissues. J Tongji Med Univ. 1997;17:28-31.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 20]  [Cited by in F6Publishing: 20]  [Article Influence: 0.8]  [Reference Citation Analysis (0)]
23.  Li KQ, Li CH. Matrix metalloproteinase and their inhibitors: molecular aspects of their roles in the tumor metastasis. Chinese J Cancer Res. 2000;12:239-243.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 4]  [Cited by in F6Publishing: 1]  [Article Influence: 0.0]  [Reference Citation Analysis (0)]
24.  Bai JT, Lu FX. Matrix metalloproteinases in relation to cardiovascular diseases. Xinxueguanbingxue Jinzhan. 2003;24:43-47.  [PubMed]  [DOI]  [Cited in This Article: ]
25.  Yao GY, Yang MT. Matrix metalloproteinases and breast cancer. Ai Zheng. 2002;21:1029-1034.  [PubMed]  [DOI]  [Cited in This Article: ]
26.  Zhu F, Liu XG, Liang NC. The relationship of matrix metalloproteinases and its tissue inhibitors to tumor invasion and metastasis. Guowai Yixue Linchuang Shengwu Huaxue Yu Jianyanxue Fence. 2001;22:229-231.  [PubMed]  [DOI]  [Cited in This Article: ]
27.  Zhao YD, Liu NF, He QL, Xu GM. Expression of MMP-3 mRNA in hypertrophic scar fibroblasts and MMP-3 gene transfection. J Med Coll PLA. 1998;13:244-248.  [PubMed]  [DOI]  [Cited in This Article: ]
28.  Li L, Zhang S, Lin H, Lin JY. Relationship of expression unbalance of matrix metalloproteinase and tissue inhibitor of metalloproteinase to invasiveness and metastasis in gastric carcinomas. Ai Zheng. 2002;21:305-310.  [PubMed]  [DOI]  [Cited in This Article: ]
29.  Lv J, Hu MJ, Cai WM. The expression of MMP-1 and TIMP-1 in peripheral mononucleocytes of patients with chronic hepatitis. Linchuang Gandanbing Zazhi. 2002;18:31-32.  [PubMed]  [DOI]  [Cited in This Article: ]
30.  Arthur MJ. Fibrogenesis II. Metalloproteinases and their inhibitors in liver fibrosis. Am J Physiol Gastrointest Liver Physiol. 2000;279:G245-G249.  [PubMed]  [DOI]  [Cited in This Article: ]