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Objective To investigate the structural distribution features and mechanism of elastic fibers and collagen fibers in ventricular interstitium of aged rats. Methods Five young SD rats (24 weeks) and five old SD rats (104 weeks) were used,and their cardiac function was examined by echocardiography. Modified Weigert elastic fiber staining, immunohistochemistry, immunofluorescence and Western blotting techniques were used to detect the expression changes of type I and IH collagen fibers and their proteins, elastic fibers and their proteins, matrix metalloproteinase 2 (MMP-2), matrix metalloproteinase 9 (MMP-9) and tissue inhibitor of metalloproteinase 2 (TIMP-2), respectively. Results The type I and type IH collagen in the ventricular interstitium of aged rats was very sufficient and wrapped around the cardiomyocytes. Compared with the young rats, the content of collagen protein in the ventricular interstitium of the aged rats significantly increased (P<0. 05). Elastic fibers in the ventricular interstitium of the aged rats were and widely distributed. Compared with the young rats, the number of elastic fibers and the level of elastin in the ventricular interstitium of the aged rats significantly decreased (P<0. 05), and the expression levels of MMP-2 and MMP-9 in ventricular muscle of aged rats increased, and the)' were correlated with the level of elastin. The level of TIMP-2 in ventricular muscle of aged rats decreased with age. Conclusion The number of collagen fibers and elastic fibers in ventricular interstitium of aged rats is fluctuated with each other. With the increase of age, the contents of TIMP-2 and elastic fibers in the ventricular interstitium gradually decreased, and the ratio of collagen fibers to elastic fibers is out of balance.
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Objective To investigate the effect of CD73 on the proliferation and function of rat cardiac myocytes (CMs) in vitro. Methods The primary rat CMs and H9C2 cells were cultured in vitro, and lentivirus CD73 overexpression vector and empty vector group were constructed and transfected into CMs and H9C2 respectively. Experimental groups: CD73 overexpression group (OE group) including CMs-OE group and CMs-NC group, and negative control group (NC group) including H9C2-OE grop and H9C2-NC group, 5 in each group. After transfection, the expression of CD73 gene was detected by Real-time PCR method, and the proliferation ability was detected by MTT method, and the proliferation curve, doubling time and pulsatility of CMs were detected by non-destructive cardiomyocyte function analyzer. Results After 72 hours of lentivirus transfection, CD73 mRNA level in the over expression group was significantly higher than that in the control group (P<0. 05); the proliferation ability of CMs and H9C2 at 3-4 days after transfection in OE group was larger than that in NC group (P<0. 05); the proliferation curve of CMs and H9C2 cells in OE group was higher than that in NC group, and the doubling time of CMs and H9C2 in OE group was lower than that in NC group 72 hours after CMs transfection, the beating rate of OE group was higher than that of NC group, the expression of T-box 5(TBX5) and the secretion of vasuular endothelial growth factor VEGF) in OE group were higher than those in NC group, while the secretion of hypoxia iducible factor-1α(HIF-1α) and tumor necrosis factor-α(TNF-α) was lower than that of NC group. Conclusion CD73 can promote the proliferation of CMs and H9C2, promote CMs pulsation, TBX5 expression and VEGF secretion, and inhibit the secretion of HIF-α and TNF-α.
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Objective To explore the relationship between the content of neuropeptide Y (NPY), calcitonin gene-related peptide (CGRP), inducible nitric oxide synthase (iNOS) and the changes of the corresponding receptors in myocardial tissue and the development of heart failure. Methods Doxorubicin was used to prepare rat heart failure models(10 rats), control group (10 rats), Cardiac ultrasound testing evaluated its cardiac function, the distribution of nerve fibers was detected by nerve staining kit method, the tissue expression levels of NPY, CGRP, iNOS and neuropeptide Y receptor Y1 (NPY1R), receptor activity modifying protein 1 (RAMP1), guanylate cyclase beta 1(GCYB1) were observed by immunofluorescence and immunohistochemical staining method. Western blotting was used to detect the protein expression levels of NPY, CGRP, iNOS and NPY1R, RAMP1, GCYB1 receptors in myocardial tissue. Results Compared with the control group, the protein expression level and tissue expression distribution of CGRP in the myocardial tissue of the heart failure group were significantly decreased (P<0.05), while the density of nerve fibers, the protein expression level and tissue expression distribution of NPY and iNOS were significantly increased (P<0.05). The protein expression levels of GCYB1 and RAMP1 in myocardial tissue of the heart failure group were significantly increased, while the protein expression levels of NPY1R were significantly decreased (P<0.05). Conclusion Heart failure can lead to remodeling of the content and distribution of nerve fibers, CGRP, NPY, iNOS and their receptors in myocardial tissue, which may be one of the causes of cardiac innervation disorders.
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Objective To investigate the expression of elastin and collagen in heart of rats with chronic heart failure and their related proteases. Methods Sprague-Dawley rat model of chronic heart failure was made by intraperitoneal injection of doxorubicin hydrochloride. Examination of cardiac function by echocardiography. ELISA and immunohistochemistry were used to detect brain natriuretic peptide ( BNP) , and Masson staining was used to detect myocardial fibrosis. The mRNA levels of elastin, I /IH collagen were detected by Real-time PCR and the expression levels of elastin, I/IH collagen, Matrix metalloproteinase (MMP)-2 and MMP-9 were detected by Western blotting. Results Compared with the control group, the heart function of rats in the model group decreased, the BNP content in serum increased, the expression of BNP in myocardial tissue was strongly positive, and the mRNA and protein expression of elastin decreased. Nevertheless, the mRNA and protein expression of I / IH collagen increased. At the same time, both MMP-2 and MMP-9 protein expression levels increased in model rat heart. Conclusion Heart failure leads to decreased expression of elastin, I /IH collagen expression increased, and the MMP-2 and MMP-9 may be involved in the regulation of this process.
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Objective To investigate the effect of fibroblast growth factor (FGF) on the proliferation and transdifferentiation of cardiac fibroblasts ( CFs ) into myofibroblasts ( MFs ). Methods Rat CFs were isolated and cultured, and then induced by FGF. CCK-8 was used to detect the cell activity and proliferation. Immunofluorescence and Western blotting were used to detect the expression of a smooth muscle actin ( α-SMA ) and collagen I ( Col I ). Results The expression and activation of α-SMA and Col I increased with the increase of CFs culture generation. The number of CFs induced by FGF did not increased significantly; the expression of α-SMA in CFs induced by FGF1 and FGF2 decreased, and the number of activated MFs decreased. Conclusion FGF family has no effect on the proliferation of CFs, but FGF1 and FGF2 can inhibit the activation of CFs and reduce the differentiation into MFs.
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Objective To study the change of vascular endothelial growth factor(VEGF) in myocardial tissue and serum of myocardial ischemia in rats.Methods Twenty SD rats were randomly divided into normal control group and test group. Test group was ligated coronary artery,and the control group was pulled on line but not ligated,then observed the change of VEGF.The histological and immunohistochemical method were used for observing the change of VEGF serum in myocardial ischemia in rats' heart.VEGF levels were measured by image analysis.Results Compared with control group,the expression of VEGF in the myocardial ischemia group was increased obviously(P
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Objective To investigate protein expression of telomerase reverse transcriptase(TERT),telomerase-associated protein 1(TP1) and telomeric repeat binding factor 2(TRF2) in human fetal cadiacmyocytes.Methods Using immunohistochemical method,sections of human fetal hearts were stained with antibodies against TERT,TP1 and TRF2.Results Expression of TERT was gradually decreased with development in human fetal cadiacmyocytes nuclear.Expression of TP1 and TRF2 was gradually increased with development in human fetal cadiacmyocytes cytoplasm.Conclusion Down-regulation of TERT and up-regulation of TP1 and TRF2 may promote the permanent withdrawal of cardiomyocytes from the cell cycle and enter terminal differentiation and myocardium hypertrophy.