目的 通过建立大鼠急性低氧运动模型,观察大鼠单个心室肌细胞瞬时外向钾电流(Ito)的改变,在细胞水平探究模拟高原低氧条件下力竭运动对心脏电生理的影响.方法 将40只健康雄性清洁级SD大鼠随机分为低氧运动组、低氧安静组、常氧运动组和常氧安静组,每组10只.利用小动物低压氧舱和常氧状态下进行力竭运动试验.取出各组大鼠心脏,利用灌流酶解法分离大鼠单个心室肌细胞,采用全细胞膜片钳技术记录大鼠单个心室肌细胞的瞬时外向钾电流.采用SPSS 20.0统计软件进行数据处理,多组间比较采用ANOVA方差分析,组间两两比较采用SNK-q检验.结果 与常氧安静组比较,+40 mV时,低氧运动组的Ito电流密度显著降低,且低于低氧安静组及常氧运动组,此效应呈现电压依赖性.门控机制研究显示,低氧运动时大鼠心肌细胞Ito稳态激活曲线失活向超极化方向移动,而稳态失活曲线则向去极化方向移动,二者综合效应使Ito电流显著降低.结论 急性低氧运动可通过改变钾通道稳态激活与稳态失活过程,降低大鼠心室肌细胞Ito,这可能是急性低氧运动导致心律失常的主要原因之一.

The incidence of atrial fibrillation (AF) increases with age, and telomere length gradually shortens with age. However, whether telomere length is related to AF is still inconclusive, and the exact mechanism by which aging causes the increased incidence of AF is still unclear. We hypothesize that telomere length is correlated with aging-related AF and that mitochondrial dysfunction plays a role in this. This research recruited 96 elderly male patients with AF who were admitted to the Second Medical Center of Chinese PLA General Hospital from April to October 2018. After matching by age and gender, 96 non-AF elderly male patients who were admitted to the hospital for physical examination during the same period were selected as controls. Anthropometric, clinical, and laboratory analyses were performed on all subjects. The mitochondrial membrane potential (MMP) of peripheral blood leukocytes was detected as the indicator of mitochondrial function. Compared with the control group, the leukocyte telomere length (LTL) was significantly shorter ( P < 0.001 ), and the level of PGC-1α in serum was significantly lower in AF patients. Additionally, in subjects without any other diseases, the AF patients had lower MMP when compared with the control. Multivariate logistic regression confirmed that LTL (OR 0.365; 95% CI 0.235-0.568; P < 0.001 ) and serum PGC-1α (OR 0.993; 95% CI 0.988-0.997; P = 0.002 ) were inversely associated with the presence of AF. In addition, ROC analysis indicated the potential diagnostic value of LTL and serum PGC-1α with AUC values of 0.734 and 0.633, respectively. This research concludes that LTL and serum PGC-1α are inversely correlated with the occurrence of aging-related AF and that mitochondrial dysfunction plays a role in this.

心血管疾病是目前威胁人类健康的头号杀手.过氧化物酶体增殖物激活受体γ共激活因子1α(PGC-1α)是能量代谢、氧化应激等生理过程中的关键因子,参与调节线粒体的生物合成,与动脉粥样硬化、冠心病、房颤、心肌病、心肌肥厚、心力衰竭等心血管疾病的发生发展密切相关.该文就PGC-1α在心血管疾病中的作用及可能机制研究进展进行综述.

目的 观察大蒜素对大鼠心力衰竭模型细胞迟后除极(DAD)、触发活动(TA)和离子流的作用及机制.方法 选取20只SD大鼠利用腹主动脉结扎法制备大鼠心力衰竭模型(模型组),另选取10只SD大鼠制作假手术组作为对照.采用酶解法急性分离2组大鼠心室肌细胞.根据实验设计对模型组是否给以大蒜素干预分为心力衰竭组(未给药)及给药组(200.0μmol/L大蒜素).膜片钳技术观察心力衰竭组、给药组及对照组细胞DAD和TA的发生,并记录相关离子流(Iti,ICa,L,INCX)的改变,以Flou-4AM荧光技术检测细胞内钙离子浓度变化.采用SPSS 17.0软件进行统计学分析.组间比较采用ANOVA分析及SNK-q检验.结果 (1)对照组、心力衰竭组及给药组细胞上DAD和TA发生率依次为[13.3％(2/15),0.0％(0/15)]、[60.0％(9/15),26.7％(4/15)]和[40.0％(6/15),13.3％(2/15)].与对照组比较,心力衰竭组细胞DAD和TA发生率显著增加;与心力衰竭组比较,给药组细胞上DAD和TA发生率显著下降,下降幅度分别为20.0％和13.4％,差异均有统计学意义(n=15,P<0.01).(2)与对照组比较,心力衰竭组心室肌细胞上ICa,L、Iti和INCX电流密度均增加,而与心力衰竭组比较,给药组上述电流均减少,其中Iti内向峰电流密度从(-1.05±0.06)pA/pF降至(-0.53±0.05)pA/pF(n=10,P<0.01),INCX内向电流密度从(-5.8±0.7)pA/pF降至(-4.2±0.4)pA/pF(n=10,P<0.01).同时,给药组通过大蒜素加速通道电流的稳态失活过程,降低ICa,L,ICa,L的峰电流密度由(-17.2±0.9)pA/pF降为(-13.5±1.0)pA/pF(n=15,P<0.01).(3)与对照组比较,心力衰竭组细胞静息态钙浓度、钙瞬变幅度和胞内钙最高50％的时间等参数显著升高;与心力衰竭组比较,上述参数在给药组细胞中均显著降低(n=15,P<0.01).心力衰竭组细胞内钙瞬变衰减率与对照组比较显著下降,而应用大蒜素后,得到显著恢复(P<0.05).结论 大蒜素可能通过减少心力衰竭大鼠心室肌细胞内的钙离子,阻滞Iti和INCX电流,从而降低心力衰竭后DAD和TA的发生.

随着人口老龄化进程,急性冠脉综合征(ACS)发生率逐渐升高,目前一些新型抗栓药物逐渐临床试验得到了认可和应用,本文就新型抗栓药物研究做一综述。

Objective To investigate the changes of ambulatory blood pressure after acute sleep deprivation of soldiers in the army.Methods Sixty healthy soldiers were studied using 24 hours acute sleep deprivation method.The ambulatory blood pressure was monitored during sleep deprivation.Results After sleep deprivation,the researched showed increases in night blood pressure load.The night systolic blood pressure(SBP)load was(55.3±37.0)% and the night diastolic blood pressure(DBP)was(26.5±28.8)%.The circadian rhythm of blood pressure and rate had disappeared.The rate of discrease was(0.5±4.8)% for SBP and(3.8±7.4)%.for DBP.Night rate depression divided by day rate depression was 4%.There was positive correlation between day rate and day SBP(r=0.269,P0.05).There was positive correlation between night rate and day DBP(r=0.338,P0.01).Blood pressure variability increased after sleep deprivation.Conclusions Acute sleep deprivation could lead to an increase in night blood pressure and the disappearance of circadian rhythm in healthy men.It could be the risk factor of hypertension and might increase the risk of cardiac attack.