RESUMO
Background: This study aimed to elucidate the effects of tumstatin (69-88) on heart failure and the underlying mechanism. Materials and methods: Myocardial infarction (MI) was induced by ligating the left coronary artery in rats to trigger heart failure. Results: Tumstatin (69-88) can reduce cardiac insufficiency in rats with heart failure. The increased cardiac fibrosis in MI rat was attenuated by tumstatin (69-88). Increase of cardiac atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in rats with myocardial infarction, and Ang II-treated NRCMs or H9C2 cells was inhibited by tumstatin (69-88). In the heart of MI rats, and Ang II-treated NRCMs or H9C2 cells, the superoxide anions and NADPH oxidase (Nox) activity rose and the superoxide dismutase (SOD) activity was reduced, which was inhibited by tumstatin (69-88). Diethyldithiocarbamate, an SOD inhibitor, increased the ANP and BNP in NRCMs or H9C2 cells. Tumstatin (69-88) inhibited the Ang II-induced raises of ANP and BNP in NRCMs or H9C2 cells, which was reversed by DETC. Conclusions: These results indicate that tumstatin (69-88) alleviates cardiac dysfunction of heart failure. Tumstatin (69-88) improves the hypertrophy of cardiomyocytes via attenuation of oxidative stress. Tumstatin (69-88) may be a potential drug for heart failure in the future.
RESUMO
Atmospheric nitrous oxide (N2O) increase contributes substantially to global climate change due to its large global warming potential. Soil N2O emissions have been widely studied, but plants have so far been ignored, even though they are known as an important source of N2O. The specific objectives of this study are to (1) reveal the effects of nitrogen and biochar addition on plant functional traits and N2O emission of Cinnamomum camphora seedlings; (2) find out the possible leaf traits affecting plant N2O emissions. The effects of nitrogen and biochar on plant functional traits and N2O emissions from plants using C. camphora seedlings were investigated. Plant N2O emissions, growth, each organ biomass, each organ nutrient allocation, gas exchange parameters, and chlorophyll fluorescence parameters of C. camphora seedlings were measured. Further investigation of the relationships between plant N2O emission and leaf traits was performed by simple linear regression analysis, principal component analysis (PCA), and structural equation model (SEM). It was found that nitrogen addition profoundly increased cumulative plant N2O emissions (+109.25%), which contributed substantially to the atmosphere's N2O budget in forest ecosystems. Plant N2O emissions had a strong correlation to leaf traits (leaf TN, P n , G s , C i , Tr, WUE L , α, ETR max, I k , Fv/Fm, Y(II), and SPAD). Structural equation modelling revealed that leaf TN, leaf TP, P n , C i , Tr, WUE L , α, ETR max, and I k were key traits regulating the effects of plants on N2O emissions. These results provide a direction for understanding the mechanism of N2O emission from plants and provide a theoretical basis for formulating corresponding emission reduction schemes.
