ABSTRACT
OBJECTIVE To study the improvement effects of arbutin on myocardial fibrosis （MF） model rats and its mechanism. METHODS The network pharmacology was used to predict the potential target of arbutin in improving MF and molecular docking was used to validated. Totally 50 SD rats were given isoprenaline subcutaneously （5 mg/kg， once a day， for 14 consecutive days） to induce the MF model. Modeled rats were randomly divided into model group， captopril group （9 mg/kg）， arbutin low-dose， medium-dose and high-dose groups （50， 100， 200 mg/kg）， with 10 rats in each group. Another 10 healthy rats were included as normal group. Each group was given the corresponding drugs， once a day， for 28 consecutive days. Twenty-four hours after the final administration， electrocardiograms and heart-related indexes [heart weight index （HWI）， left ventricular weight index （LVWI）] of rats were detected； the levels of creatine kinase （CK）， lactate dehydrogenase （LDH）， N-terminal pro-brain natriuretic peptide （NT-proBNP） and type Ⅰ collagen （Col Ⅰ） and Col Ⅲ were detected in myocardial tissue of rats； the pathological changes of myocardial tissue were observed， and protein and mRNA expressions of adenosine deaminase （ADA） and adenosine kinase （ADK） were detected in the myocardial tissue of rats. RESULTS The results of network pharmacology showed that the main targets of arbutin improving MF were ADA and ADK. The results of molecular docking showed that arbutin bind stably with ADA and ADK. The results of experimental verification showed that compared with model group， the amplitude of ST and T waves in electrocardiogram were improved in administration groups， and the symptoms of atrial flutter were alleviated； HWI （except for arbutin medium-dose group）， LVWI， the levels of CK， LDH， NT-proBNP， Col Ⅰ and Col Ⅲ in the myocardial tissue of rats were decreased significantly （P＜0.05）； the degree of myocardial fibrosis in rats decreased； protein and mRNA expressions of ADA and ADK in the myocardial tissue were significantly increased （P＜0.05）. CONCLUSIONS Arbutin can improve cardiac fibrosis and cardiac function of MF model rats， the mechanism of which may be associated with up-regulating protein and mRNA expressions of ADA and ADK，influencing the nucleotide metabolism and collagen generation. zhangminghao@hactcm.edu.cn
ABSTRACT
ObjectiveTo investigate the effect of Zhishi Xiebai Guizhitang （ZXGT） on isoproterenol （ISO）-induced myocardial infarction （MI） in rats through the tumor necrosis factor/nuclear factor-κB （TNF/NF-κB） signaling pathway. MethodForty-eight SD rats were randomly divided into control group （blank）， model group， perindopril group （4 mg·kg-1）， ZXGT group （24.4 g·kg-1）， ZXGT +inhibitor group （ZXGT， 24.4 g·kg-1， TNF-α receptor inhibitor R7050， 5 mg·kg-1）， and an inhibitor group （R7050， 5 mg·kg-1）， with eight rats in each group. The rats in each group were orally administered with their respective drugs for 7 days. Additionally， in the ZXGT + inhibitor group and the inhibitor group， R7050 was injected intraperitoneally at a dose of 5 mg·kg-1 on the 6th and 7th days. Except for the control group， all other groups were given intraperitoneal injections of ISO for 2 consecutive days to induce MI in rats. On the 7th day of the experiment， the rats were anesthetized 30 min after ISO injection， and their electrocardiograms （ECGs） were recorded to observe ST-segment elevation. Small animal echocardiography was used to measure global longitudinal strain （GLS） and cardiac synchrony. Blood samples were collected from the abdominal aorta to measure the levels of serum cardiac troponin T （cTnT）， creatine kinase-MB （CK-MB）， lactate dehydrogenase （LDH）， tumor necrosis factor-α （TNF-α）， and interleukin-1β （IL-1β）. Histopathological changes in myocardial tissue were observed using hematoxylin-eosin （HE） staining. Immunohistochemistry （IHC） was used to detect the expression of TNF-α， NF-κB p65， and p-NF-κB p65 proteins in myocardial tissue. Western blot was performed to measure the expression of tumor necrosis factor receptor 1 （TNFR1）， tumor necrosis factor receptor-associated factor 2 （TRAF2）， transforming growth factor-beta-activated kinase 1 （TAK1）， NF-κB inhibitory protein alpha （IκBα）， phosphorylated （p）-IκBα， NF-κB p65， and p-NF-κB p65 proteins in myocardial tissue. ResultCompared with the control group， the model group showed significant ST segment elevation on the ECG （P<0.01）， increased GLS， and reduced cardiac synchrony on echocardiography （P<0.01）. Histopathological examination revealed extensive myocardial necrosis. Furthermore， the serum levels of cTnT， CK-MB， LDH， TNF-α， and IL-1β were significantly increased （P<0.01）， and the expression levels of TNF-α， TNFR1， TRAF2， TAK1， p-IκBα， and p-NF-κB p65 proteins in myocardial tissue were significantly elevated （P<0.01）， while the expression level of IκBα was significantly decreased （P<0.01）. Compared with the model group， the perindopril group， the ZXGT group， the ZXGT + inhibitor group， and the inhibitor group rats showed a significant reduction in ST-segment elevation on the ECG （P<0.05， P<0.01）， improvement in GLS and cardiac synchrony （P<0.05， P<0.01）， a decrease in the area of myocardial necrosis， and reduced serum levels of cTnT， CK-MB， LDH， TNF-α， and IL-1β （P<0.01）. Additionally， the ZXGT group， the ZXGT + inhibitor group， and the inhibitor group downregulated the increased TNF-α， TNFR1， TRAF2， TAK1， p-IκBα， and p-NF-κB p65 protein expression levels and upregulated IκBα expression levels in the myocardial tissue （P<0.05， P<0.01）. No significant differences were observed between the ZXGT group and the ZXGT + inhibitor group or the inhibitor group. ConclusionZXGT can protect against ISO-induced myocardial injury in rats and improve cardiac function， and its mechanism of action may be related to the regulation of the TNF/NF-κB signaling pathway.