Effect of moxibustion combined with intraperitoneal injection of benazepril on endoplasmic reticulum stress-related protein phosphorylation in rats with chronic heart failure.

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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. 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. 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. 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.