Li Wei-Min, Sheng Li, Li Yue, Yang Bao-Feng, Gong Yong-Tai, Xue Hong-Jie, Yu Jiang-Bo, Zhang Li, Shan Hong-Bo, Liu Jie
Department of Cardiology, First Clinical Hospital, Harbin Medical University, Harbin 150001, China.
Zhonghua Yi Xue Za Zhi. 2008 Apr 8;88(14):985-9.
To evaluate the effects of oxidative stress on the protein expression of atrial calpain I and pathohistological and ultrastructural changes of atrial myocardium in atrial fibrillation (AF).
Twenty dogs were all implanted with pacemaker in a subcutaneous pocket and attached to a screw-in epicardial lead in right atrial appendage. They were randomly divided into 3 groups: sham-operation group (n = 6 without pacing), control group (n = 7 per minutes for 6 weeks), and probucol group (n = 7, pacing 1 week after recovery for 6 weeks, and administration of probucol 100 mg x kg(-1) x d(-1) 1 week before pacing till the end of pacing). One thin silicon plaque containing 4 pairs of electrodes were sutured to the right atrium. The dogs in control group, probucol group were paced at 400 beats per minutes for 6 weeks. Then the dogs were killed with their hearts taken out. The expression of atrial calpain I was measured by Western-blotting and immunohistochemistry. The pathohistological and ultrastructural changes in atrial tissue were tested by light and electron microscopy. The inducibility and duration of AF were measured in the control group and probucol group. The indexes of oxidative stress total anti-oxidation capability (T-AOC), malonyldiadehyde (MDA), and scavenging activities of superoxide anion (O2-) radical were measured by colorimetric method.
The percentage of myolysis in the left and right atria of the control group were (53.6 +/- 11.8)% and. (58.5 +/- 9.2)% respectively, significantly higher than those of the sham operation group [(4.4 +/- 3.1)% and (4.1 +/- 2.9)% respectively, both P < 0.01]. The percentage of myolysis in the left and right atria of the probucol group were (12.3 +/- 3.2)% and (12.0 +/- 2.6)% respectively, both significantly lower than those of the control group (both P < 0.01). The protein expression of calpain I of the control group was significantly higher than that of the sham-operation group, and the protein expression of calpain I of the probucol group was significantly lower than that of the control group. The AF inducibility rate after pacing of the probucol group was 60%, significantly lower than that of the control group (92.9%, P < 0.01). The average AF duration time after pacing of the probucol group was (601 +/- 328) s, significantly shorter than that of the control group (1458 +/- 498) s. The indexes of oxidative stress in probucol group were lower than the level in control group. The MDA levels of the probucol group was (3.08 +/- 0.20) mmol/mg protein, significantly lower than that of the control group (4.15 +/- 0.23) mmol/mg protein). The anti-O2- and T-AOC level of the probucol group were 279 +/- 20 U/g protein and 30.5 +/- 1.3 nmol/mg protein, both significantly higher than those of the control group (215 +/- 16 U/g protein and 25.6 +/- 1.5 nmol/mg protein respectively, both P < 0.01). There were more sarcomere vacuolization and dissolution in atrial myocytes in the control group than in the sham operation group. And the pathohistological and ultrastructural changes of the probucol were lighter than those of the control group.
Probucol prevents the pathohistological and ultrastructural changes in atrial myocardium by inhibiting calpain I expression, thus suppressing atrial structural remodeling, and preventing the induction and promotion of AF.
评估氧化应激对心房颤动（AF）时心房钙蛋白酶I蛋白表达及心房心肌病理组织学和超微结构变化的影响。
20只犬均在皮下囊袋植入起搏器，并连接至右心耳的旋入式心外膜导线。随机分为3组：假手术组（n = 6，未起搏）、对照组（n = 7，每分钟起搏400次，共6周）和普罗布考组（n = 7，恢复1周后起搏6周，起搏前1周开始给予普罗布考100 mg·kg⁻¹·d⁻¹直至起搏结束）。将一块含4对电极的薄硅片缝合至右心房。对照组和普罗布考组犬以每分钟400次的频率起搏6周。然后处死犬并取出心脏。采用蛋白质免疫印迹法和免疫组织化学法检测心房钙蛋白酶I的表达。通过光镜和电镜检测心房组织的病理组织学和超微结构变化。测量对照组和普罗布考组AF的诱发率和持续时间。采用比色法测量氧化应激指标总抗氧化能力（T-AOC）、丙二醛（MDA）和超氧阴离子（O₂⁻）自由基清除活性。
对照组左、右心房的肌溶解百分比分别为（53.6±11.8）%和（58.5±9.2）%，显著高于假手术组[分别为（4.4±3.1）%和（4.1±2.9）%，P均<0.01]。普罗布考组左、右心房的肌溶解百分比分别为（12.3±3.2）%和（12.0±2.6）%，均显著低于对照组（P均<0.01）。对照组钙蛋白酶I的蛋白表达显著高于假手术组，普罗布考组钙蛋白酶I的蛋白表达显著低于对照组。普罗布考组起搏后AF诱发率为60%，显著低于对照组（92.9%，P<0.01）。普罗布考组起搏后AF平均持续时间为（601±328）s，显著短于对照组（1458±498）s。普罗布考组氧化应激指标低于对照组水平。普罗布考组MDA水平为（3.08±0.20）mmol/mg蛋白，显著低于对照组（4.15±0.23）mmol/mg蛋白。普罗布考组抗O₂⁻和T-AOC水平分别为279±20 U/g蛋白和30.5±1.3 nmol/mg蛋白，均显著高于对照组（分别为215±16 U/g蛋白和25.6±1.5 nmol/mg蛋白，P均<0.01）。对照组心房肌细胞的肌节空泡化和溶解比假手术组更多。普罗布考组的病理组织学和超微结构变化比对照组更轻。
普罗布考通过抑制钙蛋白酶I表达预防心房心肌的病理组织学和超微结构变化，从而抑制心房结构重塑，预防AF的诱发和进展。
