Objectives: To observe the effect of moxibustion at "Xinshu"(BL15) and "Feishu"(BL13) combined with intraperitoneal injection of benazepril on cardiac function and phosphorylation of protein kinase R-like endoplasmic reticulum kinase (PERK) and eukaryotic initiation factor 2α (elF2α) proteins in myocardium of rats with chronic heart failure (CHF), so as to explore its potential mechanism underlying improvement of CHF.
Methods: A total of 42 male SD rats were randomly assigned to blank control (n=10), CHF model (n=7), medication (benazepril, n=8), moxibustion (n=8) and moxibustion+benazepril (n=9) groups, after cardiac ultrasound model identification and elimination of the dead. The CHF model was established by intraperitoneal injection of doxorubicin hydrochloride (DOX), once every week for 6 weeks. Mild moxibustion was applied to bilateral BL15 and BL13 regions for 20 min, once daily for 3 weeks. The rats of the medication group and moxibustion+benazepril group (benazepril was given first, followed by moxibustion) received intraperitoneal injection of benazepril (0.86 mg/kg) solution once daily for 3 weeks . The cardiac ejection fraction (EF) and left ventricular fractional shortening (FS) were measured using echocardiography. Histopathological changes of the cardiac muscle tissue were observed under light microscope after hematoxylin-eosin (H.E.) staining. Serum contents of B-type brain natriuretic peptide (BNP) and angiotensin Ⅱ (AngⅡ) were measured by enzyme-linked immunosorbent assay (ELISA). The expressions of phospho-PERK (p-PERK) and phospho-elF2α (p-elF2α) in the myocardium were detected by Western blot.
Results: Compared with the blank control group, the EF and FS of the left cardiac ventricle were significantly decreased (P<0.01), while the contents of serum BNP and AngⅡ, and expression levels of p-PERK and p-eIF2α significantly increased in the model group (P<0.01). In comparison with the model group, both the decreased EF and FS and the increased BNP and AngⅡ contents as well as p-PERK and p-elF2α expression levels were reversed by moxibustion, medication and moxibustion+benazepril (P<0.01). The effects of moxibustion+benazepril were markedly superior to those of simple moxibustion and simple medication in raising the levels of EF and FS rate and in down-regulating the contents of BNP, Ang Ⅱ, levels of p-PERK and p-elF2α (P<0.01, P<0.05). Outcomes of H.E. staining showed irregular arrangement of cardiomyocytes, cell swelling, vacuole and inflammatory infiltration in the model group, which was relatively milder in the 3 treatment groups. The effects of moxibustion+benazepril were superior to those of moxibustion or benazepril.
Conclusions: Moxibustion combined with Benazepril can improve the cardiac function in CHF rats, which may be related to its functions in down-regulating the expression levels of myocardial p-PERK and p-elF2α to inhibit endoplasmic reticulum stress response.
目的: 观察艾灸“心俞”“肺俞”联合贝那普利对慢性心力衰竭（CHF）大鼠心功能及心肌组织中蛋白激酶R样内质网激酶（PERK）、真核启动因子2α（eIF2α）蛋白磷酸化的影响，探讨艾灸联合贝那普利防治CHF的潜在机制。方法: 采用腹腔注射盐酸多柔比星复制CHF大鼠模型，将造模成功的SD大鼠随机分为模型组、艾灸组、药物组、艾药组，并设立空白组，每组10只。艾灸组予以艾条温和灸双侧“心俞”“肺俞”，每次20 min；药物组予以贝那普利（0.86 mg/kg）灌胃治疗；艾药组艾灸上述穴位同时予以贝那普利灌胃治疗。各组均每日治疗1次，连续干预3周。超声心动图检测大鼠心脏射血分数（EF）、左室内径缩短率（FS）；HE染色法观察心肌组织病理变化；ELISA法检测大鼠血清B型脑钠肽（BNP）和血管紧张素Ⅱ（AngⅡ）含量；Western blot法检测大鼠心肌组织磷酸化（p）-PERK、p-eIF2α的表达水平。结果: 与空白组比较，模型组大鼠EF、FS降低（P<0.01）；血清BNP和AngⅡ含量升高（P<0.01）；p-PERK、p-eIF2α蛋白表达水平升高（P<0.01）；镜下可见心肌细胞排列紊乱，出现不同程度的细胞肿胀、空泡、炎性浸润等改变。与模型组比较，艾灸组、药物组及艾药组大鼠EF、FS升高（P<0.01）；血清BNP和AngⅡ含量降低（P<0.01）；p-PERK、p-eIF2α蛋白表达水平降低（P<0.01）；镜下可见治疗后各组大鼠心肌细胞损伤减轻。艾药联合治疗效果优于艾灸组和药物组。结论: 艾灸联合贝那普利能够改善CHF，其机制与降低心肌p-PERK、p-eIF2α的蛋白表达水平，抑制心肌内质网应激反应相关。.
Keywords: Cardiac function; Chronic heart failure; Endoplasmic reticulum stress; Moxibustion.