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目的通过高脂饮食诱导方法筛选出肥胖易感(OP)大鼠和和肥胖抵抗(OR)大鼠动物模型,分析肥胖大鼠心律失常易感性的发生机制。方法高脂饲料喂饲60只健康雄性SD大鼠12周后,筛选出肥胖易感(OP)大鼠,基础组大鼠和肥胖抵抗(OR)大鼠动物模型,各组分别为15只大鼠。实验结束后,处死动物,测量体脂肪含量,并收集血清,以检测血脂水平。采用酶法分离心肌细胞,Fluo-3/AM负载后采用激光共聚焦扫描显微镜观察各组大鼠心肌细胞内钙离子强度([Ca2+]i)。结果 OP大鼠睾周脂肪、肾周脂肪、网膜脂肪、体脂比[(20.15±3.38)、(8.74±1.66)、(9.23±0.94)、(7.71±0.74)mmol·L-1]均显著高于基础组大鼠[(8.98±1.19)、(4.70±0.59)、(6.28±0.40)、(4.69±0.37)mmol·L-1]和OR组大鼠[(6.83±1.05)、(3.35±0.48)、(6.16±0.30)、(4.08±0.22)mmol·L-1],OP组与基础组和OR组比较差异有统计学意义(P<0.05);OP大鼠血清总胆固醇、甘油三酯和低密度脂蛋白水平[(1.26±0.04)、(0.58±0.10)、(0.51±0.04)mmol·L-1]显著高于基础组大鼠[(0.92±0.08)、(0.29±0.03)、(0.31±0.04)mmol·L-1]和OR组大鼠[(0.81±0.05)、(0.21±0.03)、(0.29±0.02)mmol·L-1],OP组与基础组和OR组比较差异有统计学意义(P<0.05);OP组大鼠心室肌细胞内游离钙离子荧光强度(247.96±20.03)明显高于基础组大鼠(174.25±23.13)和OR组大鼠(145.12±19.11),OP组与基础组和OR组比较差异有统计学意义(P<0.05)。结论肥胖大鼠心肌细胞内钙离子变化可能是肥胖心律失常发生机制之一。
OBJECTIVE: To screen the animal models of obesity-prone (OP) and obesity-resistant (OR) rats by high-fat diet induction and to analyze the mechanism of arrhythmia susceptibility in obese rats. Methods Sixty healthy male SD rats were fed with high-fat diet for 12 weeks. The animal models of obesity-susceptible (OP) rats, basal rats and obesity-resistant (OR) rats were screened. The rats in each group were 15 large mouse. At the end of the experiment, the animals were sacrificed, the body fat content was measured, and the serum was collected to detect the level of blood fat. Cardiomyocytes were isolated by enzymatic method and intracellular Ca2 + concentration ([Ca2 +] i) was measured by laser scanning confocal microscopy after loaded with Fluo-3 / AM. Results Compared with the control group, the peri-fat, perirenal fat, omental fat, body fat ratio [(20.15 ± 3.38), (8.74 ± 1.66), (9.23 ± 0.94), (7.71 ± 0.74) mmol·L- Were significantly higher than those in the control rats [(8.98 ± 1.19), (4.70 ± 0.59), (6.28 ± 0.40) and (4.69 ± 0.37) mmol·L-1, respectively 3.35 ± 0.48, 6.16 ± 0.30 and 4.08 ± 0.22 mmol·L-1, respectively. There was significant difference between OP group and OR group (P <0.05). The levels of serum total cholesterol, The levels of triglyceride and low density lipoprotein were significantly higher than those in the basal group [(1.26 ± 0.04), (0.58 ± 0.10), (0.51 ± 0.04) mmol·L-1] [(0.92 ± 0.08), (0.29 ± 0.03), (0.31 ± 0.04) mmol·L-1] and OR group [(0.81 ± 0.05), (0.21 ± 0.03), (0.29 ± 0.02) mmol·L-1] (P <0.05). The intracellular free calcium fluorescence intensity of ventricular myocytes in OP group (247.96 ± 20.03) was significantly higher than that in basic group (174.25 ± 23.13) and OR group 145.12 ± 19.11). There was significant difference between OP group and OR group (P <0.05). Conclusion The changes of intracellular calcium in obese rats may be one of the mechanisms of obesity arrhythmia.