| Viral myocarditis (Viral myocarditis, VMC) is the most common disease in thepediatric cardiovascular system, severity of its clinical manifestations is different, mostpatients are lighter, The therapeutic effect is better, but some children develop into chronicmyocarditis, or even progress dilated cardiomyopathy, high mortality. VMC is one of themajor cause of acquired heart disease in children, a serious threat to the physical health ofthe children. In recent years, VMC incidence show a higher trend, therefore, causedwidespread concerned. VMC pathogenesis has not yet fully clear, but generally agreed thatthe presence of the virus in the direct damage, myocardial injury, immune mechanisms anddamage of lipid peroxidation mediated, myocardial apoptosis and myocardial fibrosis. Cytokineplays a very important role in these processes. Currently there is not specific drug for VMCtreatment. Nuclear factor-related factor2(NF-E2-related factor2, Nrf2) is a newlydiscovered transcription factor that express stable in the cardiovascular system, studies haveshown that its target gene has a protective effect in cardiovascular diseases. Therefore, wehypothesized that Nrf2may be involved in the occurrence and development process of VMC.Traditional Chinese medicine was attentioned more and more in the VMC, the pueraringenerally applied to the treatment of adult cardiovascular disease, but its cardiovascularprotective mechanism of action is not fully understood, relatively few clinical experience forVMC in children, the dose also no unified requirements.The study focuses on antioxidant, anti-apoptotic, anti-fibrotic of Nrf2in VMC andexplore the role of puerarin in these areas, and high-dose applications led to the adversereaction.250BALB/c purebred4-week-old male mice weighing15±2g, randomized to thecontrol group (20), VMC group (30), the Nrf2activator CPDT of25μM groups (20),50μM(20),75μM (20), different doses of puerarin（Pue）5mg.kg-1group (20),15mg.kg-1group (20),45mg.kg-1group (20),30mg.kg-1group (20),100mg.kg-1group (30),300mg.kg-1group (30).We made model with Coxsackie B3virus (CVB3) isolates by the method of the VMCclassical. Experimental day0,4,7,14,28, we blooded, killed mice and specimens frommyocardial tissue for subsequent experiments. Myocardial cell apoptosis of mice wasdetected with flow cytometry in each group, the application of the Real-Time PCR assayNrf2mRNA, HO-1mRNA, Fas mRNA and TGF-β1mRNA level of transcription and detected protein expression of Nrf2, HO-1, Fas and TGF-β1by Western blot.We found that Nrf2mRNA and Nrf2protein expression increased with concentration of CPDT (Nrf2activator) and Pue dose increase in each group, showed a concentration or dose-dependent mannerwithin a certain range. Given large doses of Pue (≥100mg.kg-1), a dose-dependentrelationship is broken, Nrf2showing persistently elevated or no reduced state，that HO-1mRNA and protein expression was significantly increased in CPDT and Pue groups, HO-1and Nrf2were positively correlated. Within a certain range （≤45mg.kg-1）, HO-1transcription and protein expression showed a concentration or dose-dependent manner.Given large doses of Pue (≥100mg.kg-1), a dose-dependent relationship was broken, that thenumber of apoptotic cells was decrease in CPDT and Pue group from the cells, mRNA andprotein levels. Nrf2and Fas was negatively correlated. Compared Pue100mg.kg-1groupand Pue300mg·kg-1with VMC group, it showed no significant difference (P＞0.05),Which suggested therapeutic effect of the drug was not increase accordingly with the doseincreasing, that TGF-beta1mRNA and protein expression decreased in a certainconcentration or dose gradient in CPDT and Pue groups. Nrf2and TGF-beta1was negativelycorrelated. When Pue dose increased to a certain extent (≥100mg.kg-1), TGF-beta1expression did not fall but rise. We observed that high-dose Pue does not increase the role ofdrug treatment, but there is a clear diarrhea in mice, significantly increased mortality in mice,CK-MB level was significantly higher, myocardial pathological changes serious. Nrf2, HO-1,Fas, TGF-beta1mRNA and protein expression levels were change, Nrf2and HO-1, Nrf2andFas, Nrf2and TGF-beta1was no correlation.Therefore, we concluded that Nrf2expression was elevated in VMC mice, and involvedin the occurrence and development of the VMC. Nrf2had effects of antioxidant, inhibittingmyocardial apoptosis and myocardial fibrosis in the VMC. Puerarin may be antioxidativedamage, anti-cardiomyocyte apoptosis and anti-myocardial fibrosis through activating Nrf2in VMC. But It may be has other ways to play these role at the same time. Large dosepuerarin increased adverse drug reactions of diarrhea. |
PDF Full Text Request