葛根素对心肌纤维化模型大鼠左室心肌组织中转化生长因子β_1和结缔组织生长因子表达的影响

Effects of puerarin on the expression of TGF-β_1 and CTGF in left ventricle myocardial tissue of the rats with myocardial fibrosis

目的:研究葛根素对心肌纤维化模型大鼠左室心肌组织中转化生长因子β1(TGF-β1)和结缔组织生长因子(CTGF)表达的影响。方法:采用异丙肾上腺素(5mg·kg-1.d-1×10d)皮下注射诱导大鼠心肌纤维化,给予葛根素(100mg·kg-1.d-1)干预,实验共8周。32只雄性SD大鼠随机分成4组:模型组,空白对照组,葛根素早期干预组,葛根素后期干预组;每组于实验末,计算左室质量指数,取左室心肌组织进行VG染色、免疫组化染色,分别测算胶原容积积分(CVF)、CTGF蛋白和TGF-β1蛋白含量,取左室游离壁心肌组织检测羟脯氨酸浓度和运用RT-PCR半定量分析CTGFmRNA和TGF-β1mRNA水平。结果:葛根素减少模型组大鼠左室质量指数、左室心肌组织CVF及羟脯氨酸浓度(P<0.01),模型组大鼠左室心肌组织CTGF和TGF-β1的过度表达(P<0.05)。相关分析显示4组大鼠的左室心肌组织CTGF蛋白含量与左室心肌组织CVF和羟脯氨酸浓度呈正相关(P<0.05)。结论:葛根素减少心肌纤维化大鼠的左室心肌间质胶原沉积,减轻和延缓大鼠心肌纤维化,这种作用机制可能是通过抑制左室心肌组织中CTGF、TGF-β1的过度表达来实现。

Objective：To investigate the effects of puerarin on the expression of transforming growth factor beta1 （TGF-β1） and connective tissue growth factor （CTGF） in left ventricle myocardial tissue of the rats with myocardial fibrosis induced by isoprenaline （ISO）.Method：In this study,rat model of myocardial fibrosis was established by subcutaneous injection （s.c.） with ISO （0.05% ISO,5 mg/kg per day for ten days）.Meanwhile,rats were administrated by intraperitoneal injection （i.p.） with peurarin （100 mg/kg per day for 56 or 46 days）.Thirty-two male Sprague-Dawley rats weighting 150 to 170 g were devided into four groups randomly：model group （group M,n=8）,control group （group C,n=8）,early treatment with puerarin group （group Pa,n=8）,later treatment with puerarin group （group Pp,n=8）.Until day 56,left ventricle （LV） weight to body weight ratio was assessed.The cross serial transverse sections of LV of the rats were examined microscopically after Van Gieson （VG） collagen staining,CTGF-antibody immunohistochemstry （IHC） staining and TGF-β1-antibody IHC staining.The quantitative analyses of collagen volume fraction （CVF）,CTGF protein and TGF-β1 protein were performed using an image analysis computer system.CTGF mRNA level,TGF-β1 mRNA level and ratio of hydroxyproline to the total protein in LV myocardial tissue were measured.Result：When compared with model group,LV weight/ body weight ratio,CVF and ratio of hydroxyproline/total protein in LV myocardial tissue of the treatment with puerarin groups were decreased （P0.01）.Comparing with model group,the CTGF mRNA and TGF-β1 mRNA in LV myocardial tissue of the treatment with puerarin groups were significantly downregulated （P0.01,P0.05,respectively）.However,when compared with model group,the CTGF protein and the TGF-β1 protein in LV myocardial tissue the treatment with puerarin groups were markedly decreased （P0.01,P0.05,respectively）.CTGF protein was correlated with ratio of hydroxyproline/total protein and CVF in LV of rats of every group （P0.05）.Conclusion：These data demonstrated that peurarin reduced the excessive collagen deposition in cardiac interstitial of rats with chronic myocardial fibrosis induced by ISO.One of the mechanisms of the effects is related to downregulate the overexpression of CTGF and TGF-β1,two profibrotic cytokins,in LV myocardial tissue.Furthermore,the effects of early treatment with puerarin are better than those of later treatment with puerarin.