| BACKGROUND:Hypertension is the most common chronic disease, which exerts adverse effects on the target organs such as the heart, the brain,the kidney and so on, in the process of development. It is seriously impairs public health. As one of the main pathological bases in hypertension heart disease, myocardial fibrosis is a process of increased collagen deposition and the proliferation of cardiac fibroblasts (CFs), which can increase myocardial stiffness, decreasse mobility, and affect the function of ventricular diastolic and systolic, and thus can lead to serious complications of cardiac arrhythmias, heart failure and sudden cardiac death. Therefore, the resreach of the role of the pathogenesis and prevention of hypertension myocardial fibrosis has become a international hot topic in recent years.Recently, more and more research find that the pathophysiology of myocardial fibrosis during hypertension is very complicated. The process of myocardial fibrosis is regulated by the immune system, renin-angiotensin-aldosterone system (RAAS) and varties of cytokines. As one of the main factors, inflammatory cytokines play an important role in the process of myocardial fibrosis.As a new member of the tumor necrosis factor family ligands,the tumor necrosis factor (TNF) mediate by a variety of cell growth, proliferation and apoptosis, and promote the role of the inflammatory response and angiogenesis, which combine with its receptor fibroblast growth factor-induced early response protein14(Fn14). In the cardiovascular system, TWEAK/Fn14play an important role in the atherosclerotic plaque, the development of cardiomyopathy and heart failure by enhancing the inflammatory response, promoting endothelial function and raising matrix metalloproteinase. Chen et al found that can promote the proliferation and collagen synthesis of rats which can induce by activation of classic of NF-κB. In addition, studies have found that TWEAK not only activate of the classic of NF-κB pathway, and can activate the non-canonical NF-κB pathway and MAPK pathway, but related research has not reported.OBJECTIVE:To investigate the mechanism and effects of tumor necrosis factor-like inducer of apoptosis (TWEAK) on the expression of collagen I and matrix metalloproteinase-1in cardiac fibroblasts(CFs).METHODS:1. CFs were isolated by trypsin digestion method from Wistar rats and identified by invert microscope and vimentin immunofluorescence.2. Cultured CFs from neonatal Wistar rats were treated with the recombinant human TWEAK and the P38MAPK specific inhibitor (SB203580). CFs were divided into three groups:①control group:CFs were cultured without any stimulus;②TWEAK group:CFs were incubated with100ng/mL TWEAK③TWEAK+SB203580group:CFs were incubated with100ng/mLTWEAK TWEAK+SB203580.3. The CFs proliferation was examined by MTT,and the expressions of collagen I and phosphor-P38MAPK protein were detected by Western blot. qRT-PCR was used to detect the expression of collagen I mRNA. ELASA was used to detect the concentration of MMP-1in CFs cell-culture supernatant.RESULTS:1. Invert microscope, CFs appear irregular triangle or fusiform, transparent cytoplasm and big oval nucleus. When identified by immunofluore-scence,the cells showed positive for vimentin. Comply with the staining characteristics of the CFs, its purity of more than95%.2. Compared with the control group (0.302±0.019), TWEAK group (0.493±0.042) significantly promote the proliferation of CFs.The difference was statistically significant (P<0.01). TWEAK+SB203580group (0.362±0.039) can also promote the proliferation of CFs, the difference was not statistically significant (P>0.05). TWEAK+SB203580group and the TWEAK group comparison, the difference was statistically significant (P<0.05).3. The TWEAK group (6.080±0.676) and TWEAK+SB203580group (3.400±0.810) express higher than the control group(P<0.05). Compared with TWEAK, TWEAK+SB203580group type I collagen mRNA express lower level of type I collagen mRNA after specific blocking P38MAPK pathway (P<0.05).4. Compared with the control group (15±5), TWEAK group (96±15) and TWEAK+SB203580group (36±14) promote the expression of the MMP-1. Compared with TWEAK group, TWEAK+the SB203580group partly inhibit of of the expression of MMP-1(P<0.05).CONCLUSIONS:1. TWEAK group can significantly promote the proliferation of CFs, increase the expression of type I collagen mRNA,the expression of type I collagen and P-P38MAPK protein, and promote the expression of MMP-1.2. Treated with P38MAPK specific inhibitor (SB203580), it can inhibit the proliferation of Cfs and partly decrease the expression of type I collagen,P-P38MAPK protein and the expression of MMP-1. |
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