糖尿病大鼠心脏结构和功能改变的研究

Changes of Cardiac Structure and Function in Diabetic Rats

目的观察糖尿病大鼠不同病程中心脏结构和功能的改变,并探讨两者之间的关系。方法 45只雄性SD大鼠随机分组,其中腹腔注射链脲佐菌素(STZ,55 mg/kg)诱导糖尿病模型,病程4周(A1组)、8周(A2组)和12周(A3组),各10只;注射柠檬酸盐液冲服的大鼠为对照组,4周(B1组)、8周(B2组)和12周(B3组)各5只。用心脏实时三维超声诊断仪评估大鼠的心功能,Masson染色观察大鼠心脏纤维化程度并计算心肌胶原容积分数。结果 A1组左室质量指数、心肌胶原容积分数及心功能指标与B1组相比,差异无统计学意义(P>0.05)。A2和A3组左室质量指数、左室收缩内径和心肌胶原容积分数均较同期对照组显著增高(P<0.05)。与B2组比较,A2组左室短轴缩短率和左室射血分数稍下降,但差异无统计学意义(P>0.05);A3组左室短轴缩短率和左心室射血分数均低于同期对照组(P<0.05)。相关分析显示,心肌胶原容积分数与左室质量指数呈显著正相关(r=0.915,P<0.05),与左室短轴缩短率及左室射血分数呈负相关(r1=-0.903,P<0.01;r2=-0.872,P<0.05)。结论 STZ诱导的糖尿病大鼠在病程的早期即可出现心脏结构和功能的改变,随着病程的延长,心脏病变加重。

Objective To observe the changes of cardiac structure and function in diabetic rats, and explore the relationship between them. Methods Fortyfive male SD rats were randomly divided into 4,8,12 weeks diabetesgroup （group A1 , group A2 and group A3 , r = 10, each group） and 4,8,12 weeks control group （group B, group B2 and group B3 ,n = 5, each group）. Diabetic rat model was induced by a single intraperitoneal injection of streptozotocin （STZ,55 mg/kg）. The controls were injected with citrate buffer. Real-time 3D ultrasonic diagnostic equipment was used to observe cardiac function of rats. Cardiac fibrosis was observed by Masson staining and collagen volume fraction （CVF） was calculated. Results There were no significant differences in left ventricular mass index （LVMI）, CVF and cardiac function indexes between group A1 and group BL （P 〉 0.05 ）. Compared with the same-time-point control group, LVMI,left ventricular systolic dimension（LVESD） and CVF significantly increased in group A2 and group A3 （P 〈 0.05 ）. Compared with group B2 ,left ventricular fractional shortening（LVFS） and left ventricular ejection fraction （LVEF） decreased in group A2, but there were no significant differences between the two groups （P 〉 O. 05）. LVFS and LVEF were much lower in group A3 than the controls （ P 〈 0.05 ）. Correlation analysis indicated that CVF correlated positively with LVMI（r = 0.915 ,P 〈 0.05） ,while correlated negatively with LVFS and LVEF（ r_1 = -0. 903 ,P 〈 0.01; r_2 = - O. 872, P 〈 O. 05 ）. Conclusion Changes of cardiac structure and function have occurred in the early stage of diabetes induced by STZ,and the injury of heart becomes more and more severe with the progression of diabetes.