Study On Mechanisms Of Garlicin On Fibrosis Involvement In Cardiac Hypertrophy Of Pressure Overload Rat

Hypertension is one kind of common, frequently-occurring disease, which seriously impairs people's healthy in mind and body. The heart is one of impaired target organ in hypertension-related complications. Lasting pressure overload leads to adaptive change of heart structure and function, that is heart remodeling which mainly character is left ventricular hypertrophy (LVH). The adaptational process at initial stages of LVH is arm to balance increased stress on cardiac muscle, but extended overload stress leads to maladjust.Scholars and researchers consider LVH not only changes on cardiac myocytes, but also on cardiac interstitium and blood vessels. Inproportional proliferation of Cardiac interstitium constituent relative to substance constructs myocardium structural hetertogneity, that is myocardial fibrosis. Myocardial fibrosis is fibrous tissue accumulation or collagen contents alteration in heart tissue, and is the characteristic pathological change in LVH and hypertension heart disease(HHD). Excess cardiac fibrosis is a major determinant that contributes to the progression of arrhythmia, heart failure and cardiac sudden death in HHD. However, mechanisms of which are not well addressed.The present study was carried out to investigate the mechanisms responsible for myocardial fibrosis in left ventricular remodeling (LVR) and seek for effective pharmaceutical intervention. The whole study included five parts as follows:PartⅠ: Effects of Garlicin on Cardiac Hypertrophy of Pressure Overload RatObjective: To establish animal models of cardiac hypertrophy of pressure overload rats and observe effects of garlicin treated.Methods: Pressure overloaded myocardial hypertrophy was produced by banding of aorta abdominalis in male SD rats.The 90 rats randomized to 6 groups,they were groups of Sham, Control, Garlicin 1, Garlicin 2, Tetramethylpyrazine(TMP), Losartan, respectively. The rats were administered with drugs 3d after operation, They were examined by echocardiography on after 30 days treatment, then were sacrificed. Portions of heart were processed for histological and morphological examination,blood samples were obtained to conduct subsequent biochemical analysis.Results:LVH and dysfunction were verified by echocardiography. systolic function of left ventricular is on compensation phase, myocardial hypertrophy of this model belongs to concentric hypertrophy, the thickness of ventricular wall increased and volume decreased. Garlicin treatment could lead to certain lessening. Heart weight/body weight lowered in comparison with controls, LVH was seen in hearts of rats on 30 days after operation, Garlicin treated could ameliorate this pathological change.Conclusion:It showed that Garlicin can prevent cardiac remodeling of hypertrophy cardium induced by pressure over-load including myocardial hypertrophy.。PartⅡ:Effects of Garlicin on Myocardial Fibrosis of Pressure Overload RatsObjective: To observ effects of garlicin on myocardial fibrosis of pressure overload rats.Methods: We detected hydroxyproline(HOP) of left ventricular and carboxy terminal propeptide of procollagen type I (PⅠCP), amino terminal propeptide of procollagen type III(PⅢNP), hyaluronic acid (HA), laminin(LN) of serum. hearts were processed for histological and morphological examination.Results: Histological and serological findings showed that was reparative fibrosis, promotion of synthesis and lightened degradation of cardiac collagens were presented in heart tissue of model rats. Garlicin treatment could reduce HOP of left ventricular, PⅠCP, PⅢNP and HA of serum in comparison with controls. Garlicin could also ameliorate collagen surrounding blood vessel in heart histologically.Conclusion: It showed that Garlicin can prevent myocardial fibrosis of hypertrophy cardium induced by pressure over-load.PartⅢ: Decreasing AngⅡand Ameliorating Peroxidative Stress of Pressure Overload Rats by Garlicin treatmentObjective: To observ effects of Garlicin on AngⅡand SOD, MDA of pressure overload rats.Methods:we detected AngⅡo f blood plasma and left ventricular and superoxide anion (SOD) and malondialdehyde (MDA) of serum.Results: Pressure overload could induce increasing AngⅡstandard of blood plasma and left ventricular on SD rats. Garlicn could decrease circulating and regional abnormal AngⅡ. SOD activity of models decreased and MDA content of models increased in comparison with sham group. Pressure overload resulted in peroxidative damage in myocardial fibrosis. Garlicn could inhibit MDA and enhance SOD.Conclusion: Garlicn could decrease circulating and regional abnormal AngⅡ. Pressure overload resulted in peroxidative damage in myocardial fibrosis. Garlicn could inhibit MDA and enhance SOD.PartⅣEffects of Garlicin on Fibroblasts Proliferation and Collagen Excrete Objectiv: Investigating the effects of Garlicin on fibroblasts proliferation and collagen excretion to explore its anti-fibrosis mechanisms. the effects of garlicin on fibroblasts proliferation and collagen synthesis, to explore its anti-fibrosis mechanism.Methods: The rate of proliferation is determined by the incorporation of H3-thymidine into NIH3T3 cellular nucleic acids. We observed apoptosis on NIH3T3 cells through DNA ladder experiment. TypeⅠcollagen expression was detected by immunofluorescent microscopy. Analysising of hydroxyproline in cell culture medium based alkaline hydrolysis.Results: Garlicin could inhibit DNA synthesis in NIH3T3 fibroblasts and TypeⅠcollagen expression from 0.2 ug/ml to 5ug/ml. Garlicin also reduced hydroxyproline in cell culture medium. But we could not obserse apoptosis through DNA ladder experiment.Conclusion: Garlicin could depress fibroblasts expressing typeⅠcollagen and proliferating.PartⅤ: Influence of Garlicin on TGF-β1 Signal Transmit Passway Involvement in Myocardial FibrosisObjectiv: Investigating the influence of garlicin on TGF-β1 signal transmit passway involvement in myocardial fibrosis.Methods: detecting TGF-β1 of serum by ELISA and TGF-β1 protein expression on rats'heart by immunohistochemistry. Testing Smad2 and Smad7 mRNA expression in heart by Real-time PCR. At the same time, garlicin effected on TGF-β1 signal transmit passway was evaluated by a luciferase assay using Mv1Lu-(CAGA)12-Luc cell line responsing to TGF-β.Results: TGF-β1 of serum and TGF-β1 protein expression on rats'heart all increased in model group than sham group. Garlicin could inhibited the abnormal enhancement. Real-time RT- PCR result manifested Smad2 mRNA up-regulated and Smad7 mRNA down-regulated. Garlicin treatment could inhibit Smad2 and promoted Smad7 and lead to TGF-β1 inclining to normal standard. In vitro experiment, the luciferase activity responding to TGF-βwas inbibited obviously in 1ug/mL garlicin group under the stimulation of 2ng/mL TGF-β1 and Its inhibition ratio was about 20%. the larger dose (5ug/mL) weakened this effect.Conclusion: Pressure overload activated TGF-β1 signal transmit passway of rats. Garlicin could relieve this passway in certain degree.