ABSTRACT
This study was to investigate the protective effects of puerarin on myocardial ischemia/reperfusion (MI/R) injury and the underlying mechanism. The MI/R-model was established by ligating the left anterior descending artery (LAD) for 60 min followed by 24 h reperfusion, puerarin (10, 30, and 100 mg·kg-1) was orally administered 20 min before reperfusion. Cardiac function, myocardial infarct index, cardiac damage markers, inflammatory cytokines, and apoptosis index were measured to evaluate the protective effects of puerarin on MI/R injury. The activation of Nod-like receptor protein 3 (NLRP3) inflammasome and Toll like receptor 4 (TLR4)/myeloid differentiation factor 88 (Myd88)/nuclear factor kappa B (NF-κB) pathway were determined by Western blot. All animal experimental procedures were approved by the ethics committee of the Institute of Materia Medica, Peking Union Medical College, Chinese Academy of Medical Sciences. The results showed that puerarin could significantly improve cardiac function, reduce myocardial infarct size, decease the levels of lactic dehydrogenase (LDH), aspartate transaminase (AST), creatine kinase-MB (CK-MB), and cardiac troponin T (cTnT) and suppress cardiomyocyte apoptosis. Meanwhile, puerarin could notably decrease the levels of inflammatory cytokines such as interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α). Western blot analysis revealed that puerarin could downregulate the expression of TLR4, Myd88, NLRP3, apoptosis-associated speck-like protein containing a CARD (ASC), cleaved-caspase 1, cleaved-gasdermin-D (GSDMD), IL-1β, and IL-18, as well as the phosphorylation levels of inhibitor of NF-κB α (IκBα), IκB kinase β (IKKβ), and NF-κB. These findings demonstrated that puerarin could alleviate MI/R injury by suppressing NLRP3 inflammasome activation, possibly via TLR4/Myd88/NF-κB pathway.
ABSTRACT
OBJECTIVE To investigate the effects of total flavonoids of bugloss(TFB)on left ventricular (LV)remodeling after myocardial infarction(MI),LV size and function was compared in mice subjected to left anterior descending coronary artery ligation. METHODS 28 d after MI, the infarcted fraction of the LV and LV mass, systolic and diastolic function were measured. Capillary density and myocyte width in the nonischemic portion of the LV were also determined.RESULTS 28 d after MI,both groups had dilated LVs with decreased fractional shortening and lower ejection fractions. Although the infarcted size of the LV was similar in both groups,LV end-diastolic internal diameter,end-diastolic volume,and mass were lower, but fractional shortening, ejection fraction, and the maximum rate of developed LV pressure(dp/dtmax)were greater in TFB treated mice than in control mice.Impairment of diastolic func-tion, as measured by the time constant of isovolumic relaxation (t) and the maximum rate of LV pres-sure decay(dp/dtmin),was more marked in control mice than in TFB treated mice.Mortality after MI was greater in control mice than in TFB treated mice.In control mice,capillary density and myocyte width in the nonischemic portion of the LV did not differ before and 28 days after MI, whereas in TFB treated mice, capillary density increased and myocyte width declined after MI. CONCLUSION These results suggest that the presence of TFB limits LV dysfunction and remodeling in a murine model of MI in part by decreasing myocyte hypertrophy in the remote myocardium.