异丙肾上腺素致大鼠心肌损伤肥大时骨架蛋白的变化及意义

Role and alteration of cytoskeleton proteins in rat myocardial lesions and hypertrophy induced by isoproterenol

目的复制异丙肾上腺素(isoproteronol,Iso)致大鼠心肌损伤及肥大模型,观察细胞骨架蛋白微管蛋白(tubulin)、结蛋白(desmin)变化特点,探讨心肌支持蛋白在心肌肥厚过程中的关系和变化规律,为抑制心室肥厚的发生和发展提供实验依据。方法①将雄性Wistar大白鼠随机分成对照组和损伤肥大组(Iso组)。Iso组皮下多点注射中等剂量Iso,建立大鼠损伤、代偿性肥厚模型。②光镜观察心肌组织的病理变化。③RT-PCR法检测tubulin、desminmRAN表达。④免疫组化法检测tubulin、desmin蛋白表达。结果光镜下Iso组心肌组织有明显的损伤肥大及纤维化,tubulinmRNA(0.9252±0.3765)和desminmRNA(1.2453±0.5326)表达与对照组(0.6846±0.2372)和(0.7142±0.1416)比较明显升高,差异有统计学意义(t=2.3258,P<0.05;t=4.0972,P<0.01)。Iso组tubulin(0.75±0.32)和desmin(0.85±0.29)蛋白表达与对照组(0.56±0.25)和(0.64±0.31)比较,差异也有统计学意义(t=2.5627,P<0.05;t=2.7544,P<0.01)。结论Iso致大鼠心肌损伤肥大时,tubulin、desmin无论在蛋白水平,还是在基因水平都增加,提示异丙基肾上腺素对大鼠心肌tubulin、desmin蛋白水平和基因水平的影响是平行、一致的。

Objective To establish a rat model with myocardial lesions an d hypertrophy induced by isoproterenol and to investigate the roles of the cytos keleton alteration and its relationship with cardiac hypertrophy, thus to provid e an experimental basis for the inhibition of the genesis and progression of car diac hypertrophy. Methods Wistar rats were randomly divided into Iso-group an d control group. The rat model with cardiac lesions and compensative hypertrophy was established by subcutaneous injection in multiple sites with intermediate d osage of Iso. Pathological changes were observed by light microscope. The expres sion of tubulin and desmin were analyzed with RT-PCR and immunohistochemical met hods. Results Significant lesions, hypertrophic and fibrosis were observed un der light microscope. In the Iso-group, the mRNA levels of both tubulin(0.925 2 ± 0.376 5) and desmin(1.245 3 ± 0.532 6) increased significantly(t = 2.325 8,P < 0.05; t = 4.097 2,P < 0.01) compared with those in control group(0.684 6 ± 0 .237 2; 0.714 2 ± 0.141 6). In the Iso-group,the expressions of tubulin protein (0.75 ± 0.32) and desmin protein(0.85 ± 0.29) also increased significantly (t = 2.562 7,P < 0.05; t = 2.754 4,P < 0.01) compared with those in control group( 0.56 ± 0.25; 0.64 ± 0.31). Conclusions The expressions of tubulin and desm in increase at both gene and protein level in myocardial lesions and hypertrophy induced by isoproterenol, indicating that isoproterenol affects expressions of tubulin and desmin at both gene and protein level. [