生长激素释放肽-2对自发性高血压大鼠心肌纤维化的抑制作用

摘要

Objective To investigate whether growth hormone releasing peptide-2 (GHRP-2) could attenuate cardiac fibrosis in spontaneously hypertensive rats (SHR).Methods SHR shows severe cardiac fibrosis and were used as a model of cardiac fibrosis in this study.SHR were treated with GHRP-2 (100μg/kg,sc,qd) for4 weeks starting from the 12th week of birth.Picro-sirius red staining was used to visualize type Ⅰ and type Ⅲ collagens,Van Gienson staining was applied to visualize total collagens,and hydroxyproline assay was used to quantitatively evaluate the synthetic level of myocardial collagen.Results Compared with control Wistar rats,GHRP-2 treatment significantly decreased the levels of type Ⅰ and type Ⅲ collagens and the total collagens,and also reduced the level of hydroxyproline.Conclusion GHRP-2 attenuates cardiac fibrosis via suppressing cardiac synthesis of collagens.%目的 研究生长激素释放肽-2(GHRP-2)是否可抑制心肌纤维化.方法 由于自发性高血压大鼠(SHR)存在自然发生的严重心肌纤维化,本研究利用SHR作为心肌纤维化模型.SHR从12周龄开始给予GHRP-2皮下注射治疗(100μg/kg,每日1次,共4周),同龄Wistar大鼠皮下注射等量生理盐水作为正常对照组;利用苦味酸天狼猩红染色法显示SHR左心室肌Ⅰ型胶原和Ⅲ型胶原,用Van Gienson染色法显示左心室总胶原水平;用羟脯氨酸含量测定法评估心肌中胶原合成水平.结果 与正常对照组相比,未经处理的SHR左心室肌中Ⅰ型和Ⅲ型胶原明显增多,羟脯氨酸含量也显著增高.GHRP-2治疗可明显降低SHR心肌中Ⅰ型、Ⅲ型胶原和总胶原的水平,并降低羟脯氨酸含量.结论 GHRP-2可以通过抑制胶原合成而减轻SHR左心室纤维化.