性别对成年小鼠心肌细胞收缩力的影响

摘要

Objective To explore the effect of gender on the contractility and calcium transient of adult C57BL/6 mouse cardiomyocytes.Methods Adult mouse cardiomyocytes were isolated by retrograde perfusion of collagenase Ⅱ enzymolysis with Langendorff perfusion system.The morphological differences of the two groups (male and female) of mouse cardiomyocytes were compared.Sarcomere length and calcium transient changes of both male and female under field stimulation were recorded synchronously with IonOptix Myocyte Calcium and Contractility System.Parameters that reflect cardiomyocyte contractility such as the sarcomere shortening amplitude,sarcomere shortening rate,the maximal systolic rate,the maximal diastolic rate,and those reflect calcium transient such as peak calcium transient,calcium transient amplitude,and calcium decay time constant were analyzed and compared between the two groups.Results The sarcomere length peak height [(0.14 ±0.02) μm vs.(0.08 ±0.01) μm],sarcomere shortening rate(7.47％ ±0.93％ vs.4.60％ ± 0.59％),the maximal systolic rate [(-3.25 ± 0.37) μm/s vs.(-2.11 ± 0.38) μm/s],and the maximal diastolic rate [(2.45 ± 0.29) μm/s vs.(1.57 ± 0.31) μm/s] of adult male C57BL/6 mice were apparendy larger than that of female.The calcium transient peak and calcium transient amplitude were also much greater than female.Accordingly,the calcium decay time constant [(122.40 ± 22.99) ms vs.(189.20 ± 19.54)ms] of adult male C57BL/6 mouse cardiomyocytes was smaller compared with that of female.Conclusions Compared with the female mice,male C57/BL6 mice have greater cardiomyocyte contractility and calcium transient.%目的 研究性别对成年C57BL/6小鼠心肌细胞收缩力和钙瞬变的影响. 方法 采用Langendorff逆行灌流、Ⅱ型胶原酶消化方法分离不同性别成年C57 BL/6小鼠心肌细胞,比较两组心肌细胞的形态学差异;运用IonOptix细胞收缩及离子浓度同步测量系统,同步记录不同性别小鼠心肌细胞肌节长度及钙瞬变随电刺激的变化,比较两组间心肌细胞收缩力(肌节缩短幅度、肌节缩短率、肌节最大收缩速度和最大舒张速度)和心肌细胞钙瞬变(钙瞬变峰值、钙瞬变幅度和钙离子消除时间常数)的差异. 结果 成年雄性C57BL/6小鼠心肌细胞收缩力指标:肌节缩短幅度[(0.14±0.02) μm比(0.08 ±0.01) μm]、肌节缩短率(7.47％ ±0.93％比4.60％±0.59％)、肌节最大收缩速度[(-3.25±0.37)μm/s比(-2.11±0.38)μm/s]和肌节最大舒张速度[(2.45±0.29) μm/s比(1.57 ±0.31) μm/s]明显高于雌性小鼠(均为P＜0.05).此外,成年雄性C57BL/6小鼠心肌细胞钙瞬变指标钙瞬变峰值和钙瞬变幅度亦显著高于雌性小鼠(均为P＜ 0.05),而雄性小鼠心肌细胞钙离子消除时间常数低于雌性小鼠[(122.40±22.99)ms比(189.20±19.54)ms,P＜0.05]. 结论 成年雄性C57BL/6小鼠的心肌细胞收缩力及钙瞬变均高于雌性小鼠.