压力超负荷大鼠心肌胶原代谢的动态变化

目的:探讨压力超负荷大鼠心肌胶原代谢的动态变化。方法:采用腹主动脉缩窄法制备压力超负荷大鼠模型,并以假手术组为对照,分别于术后第3周、4周、8周和12周取材,称量大鼠体质量、心脏质量和左心室质量,计算心脏质量指数(heart mass index,HMI)和左心室质量指数(left ventricle mass index,LVMI);心肌组织Masson染色观察心肌胶原纤维沉积情况;样本碱水解法检测心肌组织羟脯氨酸(hydroxyproline,HYP)含量;ELISA法检测血清Ⅰ型前胶原羧基端肽(procollagen typeⅠcarboxy-terminal peptide,PⅠCP)、Ⅲ型前胶原氨基端肽(procollagen typeⅢamino-terminal peptide,PⅢNT)和Ⅰ型胶原C端肽(collagen C telopeptide typeⅠ,CTX-Ⅰ)水平。结果:与假手术组相比,模型组大鼠心肌血管周围及间质可见胶原纤维沉积,心肌胶原容积分数明显增高(P0.01),且随时间延长胶原沉积明显增多;模型组大鼠HMI、LVMI和HYP均明显增加(P0.05),且随时间延长大鼠HYP有升高的趋势;模型组大鼠血清PⅠCP浓度显著升高,在第4、8和12周时差异有统计学意义(P0.05);模型组大鼠血清PⅢNP浓度显著升高,CTX-Ⅰ浓度显著降低,差异均有统计学意义(P0.01)。结论:压力超负荷状态下,心肌胶原代谢紊乱,且随时间的延长心肌呈不同程度的纤维化表现。

Dynamic changes of myocardial collagen metabolism in pressure-overloaded rats

AIM: To observe the dynamic changes of myocardial collagen metabolism in pressure-overloaded rats.METHODS: The pressure-overloaded rat model was established by partial abdominal aortic coarctation. The rats underwent surgery but not constrictive were used as sham-operated control group. The rats were euthanized at 3, 4, 8 and 12 weeks. The body mass, heart mass and left ventricular mass were weighed, and the heart mass index (HMI) and left ventricle mass index (LVMI) were calculated. Masson trichrome staining was used on the myocardial sections, alkaline hydrolysis was used to detect the content of myocardial hydroxyproline (HYP), and the serum levels of procollagen type I carboxy-terminal peptide (PICP), procollagen type III amino-terminal peptide (PIIINT), and collagen C telopeptide type I (CTX-I) were also measured. RESULTS: Compared with sham-operated control group, the collagen deposition was evident, and collagen volume fraction (CVF) was increased significantly in model group (P<0.01), which further increased over time. HMI, LVMI and HYP significantly increased in model group (P<0.05), and HYP showed a tendency to increase over time. In addition, the serum concentration of PICP was increased significantly in model group, and the difference was significant at 4, 8 and 12 weeks (P<0.05). The serum concentration of PIIINP was increased significantly, but CTX-I was lowered significantly in model group (P<0.01). CONCLUSION: In the state of pressure overload, myocardial collagen metabolism is in disorder, and myocardial fibrosis is the major pathological change, which further increases over time.