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目的观察不同病程糖尿病(DM)模型大鼠心脏功能、心脏指数、心肌形态的变化并探讨其相关性。方法将SD大鼠随机分为4组,对照组8周组和12周组,DM模型大鼠8周组和12周组,每组10只。对照组正常饲料喂养,采用链脲佐菌素50mg/kg诱发DM大鼠模型。测定各组大鼠左心室收缩压(LVSP)、左心室舒张末期压(LVEDP)、室内压最大上升速率(+dp/dtmax)、室内压最大下降速率(-dp/dtmax)、室内压上升达最大速率所需时间(t-dp/dt)和心脏指数,采用光学显微镜及电子显微镜观察心肌结构改变。结果与对照组比较,8周时DM组大鼠LVEDP明显升高,-dp/dtmax明显降低,差异均有统计学意义(均P<0.05);12周时LVEDP进一步升高,-dp/dtmax进一步降低,LVSP、+dp/dtmax显著降低,t-dp/dt显著延长,差异均有统计学意义(均P<0.01)。8周时DM组大鼠体重、心脏重量和左心室重量均明显低于对照组大鼠,但心脏指数和左心室指数则明显高于对照组大鼠,差异均有统计学意义(P<0.05)。12周时DM组体重几乎无增长,心脏重量和左心室重量显著低于对照组大鼠,心脏指数和左心室指数显著高于对照组大鼠,差异均有统计学意义(均P<0.01)。8、12周时,DM大鼠均有明显的心肌结构的改变,以12周改变更为明显。结论糖尿病大鼠出现心肌超微结构的改变,导致左室肥厚及心脏功能受损,且随病程的延长而进一步加重。
Objective To observe the changes of cardiac function, cardiac index and myocardial morphology in diabetic rats with different course of diabetes mellitus (DM) and explore their correlation. Methods SD rats were randomly divided into 4 groups, control group 8 weeks and 12 weeks group, DM model 8 weeks group and 12 weeks group, 10 rats in each group. Control group fed normal diet, streptozotocin 50mg / kg induced DM rat model. The left ventricular systolic pressure (LVSP), left ventricular end-diastolic pressure (LVEDP), maximal rate of increase of indoor pressure (+ dp / dtmax), maximal rate of decrease of indoor pressure (-dp / dtmax) The maximum rate of time required (t-dp / dt) and cardiac index, the use of optical microscopy and electron microscopy myocardial structural changes. Results Compared with the control group, LVEDP was significantly increased and -dp / dtmax was significantly decreased in DM group at 8 weeks (all P <0.05), LVEDP was further increased at 12 weeks, and -dp / dtmax Further reduction, LVSP, + dp / dtmax decreased significantly, t-dp / dt significantly prolonged, the difference was statistically significant (all P <0.01). At 8 weeks, body weight, heart weight and left ventricular weight in DM group were significantly lower than those in control group, but cardiac index and left ventricular index were significantly higher than those in control group (P <0.05 ). There was almost no increase in body weight, heart weight and left ventricular weight in DM group at 12 weeks, and cardiac index and left ventricular index were significantly higher than those in control group (all P <0.01) . At 8 and 12 weeks, there was a significant change of myocardial structure in DM rats, which was more obvious at 12 weeks. Conclusion The ultrastructural changes of myocardium in diabetic rats resulted in impaired left ventricular hypertrophy and cardiac function, and further aggravated with the prolongation of the course of disease.