Graduate School of Anhui University of Chinese Medicine, Hefei 230012, China.
Key Laboratory of Meridian and Viscera in Anhui Province, Hefei 230038.
Zhen Ci Yan Jiu. 2024 Jun 25;49(6):558-565. doi: 10.13702/j.1000-0607.20221393.
To observe the effect of electroacupuncture (EA) at "Neiguan"(PC6) on cardiac function, cardiac morphology and transient receptor potential channel (TRPC) protein expressions in myocardial tissue of mice with myocardial hypertrophy, so as to explore its mechanisms underlying improvement of myocardial hypertrophy.
Forty-five male C57BL/6 mice were randomly divided into control, model and EA groups (15 mice/group). The myocardial hypertrophy model was established by subcutaneous injection of isoproterenol hydrochloride (15 mg·kg·d) for 14 days. The mice of the control group received subcutaneous injection of same amount of normal saline. The mice of the EA group received EA stimulation (frequency of 2 Hz, intensity of 1 mA) of bilateral PC6 for 20 min each time, once a day for 14 consecutive days. After the intervention, the body weight, tibia length and heart weight were measured. The left ventricular ejection fraction (EF), fractional shortening index (FS), left ventricular end-systolic volume (LVEV), left ventricular end-systolic internal diameter (LVID) and left ventricular posterior wall thickness (LVPW) were measured by using echocardiography for evaluating the cardiac function. The mean number and surface area of myocardial cells was detected by wheat germ agglutinin (WGA) staining, and changes of the cardiac morphology were observed under light microscopy after HE staining. The expression levels of TRPC1, TRPC3, TRPC4 and TRPC6 (TRPC1/3/4/6) in the myocardial tissue were detected by real-time quantitative PCR (qPCR) and Western blot, separately.
Compared with the control group, the heart-body weight ratio(<0.05) and heart-weight-to-tibia-length ratio (<0.01), LVEV and LVID levels, the relative surface area, left ventricular area ratio, and the expression levels of cardiac TRPC1/3/4/6 were significantly increased (<0.01, <0.05), while the EF, FS, LVPW, number of cardiomyocytes, and the left ventricular posterior wall ratio were obviously decreased (<0.01, <0.05) in the model group. In comparison with the model group, the heart/body weight ratio, heart-weight-to-tibia-length ratio, LVEV and LVID levels, relative surface area, left ventricular area ratio, and the expression levels of cardiac TRPC1/3/4/6 were significantly decreased (<0.01, <0.05), while the EF, FS, LVPW, number of cardiomyocytes and left ventricular posterior wall ratio were significantly increased (<0.01, <0.05) in the EA group. H.E. staining showed disordered arrangement of cardiomyocytes and obvious myocardial interstitial inflammatory cell infiltration in the model group, and evident reduction of degree of cardiac fibrosis and interstitial edema in the EA group.
EA of PC6 can improve the cardiac function and cardiac morphology in mice with myocardial hypertrophy, which may be related to its functions in down-regulating the expression of transient receptor potential channels.
观察电针内关穴对心肌肥厚模型小鼠心功能、心脏形态学及心肌组织瞬时受体电位通道（TRPC）蛋白表达的影响，探讨其改善心肌肥厚的作用机制。
45 只雄性 C57BL/6 小鼠随机分为对照组、模型组和电针组（每组 15 只）。采用皮下注射盐酸异丙肾上腺素（15mg·kg·d）的方法制备心肌肥厚模型，连续 14 天。对照组小鼠皮下注射等体积生理盐水。电针组小鼠每天接受双侧内关穴（PC6）电刺激（频率 2Hz，强度 1mA），每次 20min，连续 14 天。干预结束后，测量小鼠体质量、胫骨长度和心脏质量。采用超声心动图检测左心室射血分数（EF）、缩短分数指数（FS）、左心室舒张末期容积（LVEV）、左心室舒张末期内径（LVID）和左心室后壁厚度（LVPW），以评估心功能。采用小麦胚凝集素（WGA）染色检测心肌细胞的平均数量和表面积，并通过 HE 染色观察心脏形态的变化。采用实时定量 PCR（qPCR）和 Western blot 分别检测心肌组织中 TRPC1、TRPC3、TRPC4 和 TRPC6（TRPC1/3/4/6）的表达水平。
与对照组比较，模型组的心体质量比（<0.05）和心脏质量/胫骨长度比（<0.01）、LVEV 和 LVID 水平、相对表面积、左心室面积比和心脏 TRPC1/3/4/6 的表达水平明显升高（<0.01，<0.05），EF、FS、LVPW、心肌细胞数量和左心室后壁比明显降低（<0.01，<0.05）。与模型组比较，电针组的心体质量比、心脏质量/胫骨长度比、LVEV 和 LVID 水平、相对表面积、左心室面积比和心脏 TRPC1/3/4/6 的表达水平明显降低（<0.01，<0.05），EF、FS、LVPW、心肌细胞数量和左心室后壁比明显升高（<0.01，<0.05）。HE 染色显示模型组心肌细胞排列紊乱，心肌间质炎症细胞浸润明显，电针组心肌纤维化和间质水肿程度明显减轻。
电针内关穴可改善心肌肥厚模型小鼠的心功能和心脏形态，其作用机制可能与下调瞬时受体电位通道的表达有关。
