Mechanism of Zhishi Xiebai Guizhitang in Alleviating Myocardial Injury in Rats with Myocardial Infarction Based on TNF/NF-κB Signaling Pathway / 中国实验方剂学杂志

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.