No abstract

Tanshinone IIA has definite protective effects on various cardiovascular diseases. However, in hypertension-induced left ventricular hypertrophy (H-LVH), the signaling pathways of tanshinone IIA in inhibition of remodeling and cardiac dysfunction remain unclear. Two-kidney, one-clip induced hypertensive rats (n = 32) were randomized to receive tanshinone IIA (5, 10, 15 mg/kg per day) or 5% glucose injection (GS). Sham-operated rats (n = 8) received 5%GS as control. Cardiac function and dimensions were assessed by using an echocardiography system. Histological determination of the fibrosis and apoptosis was performed using hematoxylin eosin, Masson’s trichrome and TUNEL staining. Matrix metalloproteinase 2 (MMP2) and tissue inhibitor of matrix metalloproteinases type 2 (TIMP2) protein expressions in rat myocardial tissues were detected by immunohistochemistry. Rat cardiomyocytes were isolated by a Langendorff perfusion method. After 48 h culture, the supernatant and cardiomyocytes were collected to determine the potential related proteins impact on cardiac fibrosis and apoptosis. Compared with the sham rats, the heart tissues of H-LVH (5%GS) group suffered severely from the oxidative damage, apoptosis of cardiomyocytes and extracellular matrix (ECM) deposition. In the H-LVH group, tanshinone IIA treated decreased malondialdehyde (MDA) content and increased superoxide dismutase (SOD) activity. Tanshinone IIA inhibited cardiomyocytes apoptosis as confirmed by the reduction of TUNEL positive cardiomyocytes and the down-regulation of Caspase-3 activity and Bax/Bcl-2 ratio. Meanwhile, plasma apelin level increased with down-regulation of APJ receptor. Tanshinone IIA suppressed cardiac fibrosis through regulating the paracrine factors released by cardiomyocytes and the TGF-β/Smads signaling pathway activity. In conclusion, our in vivo study showed that tanshinone IIA could improve heart function by enhancing myocardial contractility, inhibiting ECM deposition, and limiting apoptosis of cardiomyocytes and oxidative damage.

It is known that apelin has definite protective effects on various cardiovascular diseases; however, the mechanism through which hypertension with heart failure (H-HF) is affected by pyroglutamylated apelin-13 (Pyr-AP13) remain unclear. Thus, in the present study, we investigated the effects of apelin on the cardiac hemodynamics in rats with hypertension and heart failure. In our study, cardiac function, dimensions and histological determination of the fibrosis of rats with two-kidney, one-clip induced hypertension and sham-operated rats were assessed using an echocardiography system and Masson’s trichrome. The infusion of either 5% glucose injection (GS) alone or 5% GS containing Pyr-AP13 as a dose, time-matched design on the cardiac hemodynamics in H-HF rats and sham-operated rats was recorded. For the determination of the effects of potential related proteins on cardiac hemodynamics in the H-HF rats, the animals were divided into 5 groups: i) the sham-operated group (n=8); ii) H-HF (n=8); iii) H-HF with infusion of 0.1 μg dose of Pyr-AP13 (n=8) or 5% glucose (GS) (n=8); iv) H-HF with infusion of 1 μg dose of Pyr-AP13 (n=8) or 5% GS (n=8); and v) H-HF with infusion of 10 μg dose of Pyr-AP13 (n=8) or 5% GS (n=8). The concentration of cyclic adenosine 3′,5′-monophosphate (cAMP) was determined by ELISA. The expression of membrane and cytosolic proteins was evaluated by western blot analysis. Significant cardiac and perivascular fibrosis was observed in the H-HF rats. Following the infusion of Pyr-AP13, the systolic and diastolic function was significantly improved in the cardiac hemodynamic parameters in the H-HF rats treated with Pyr-AP13. The apelin receptor (APJ), which was activated by the exogenous infusion of Pyr-AP13, was partially recycled from the cytoplasm back to the plasma membrane; however, membrane APJ was eventually downregulated in the H-HF rats treated with Pyr-AP13 compared with the sham-operated group rats. Our findings suggested that a complex was formed after Pyr-AP13 combined with cellular membrane APJ receptor. However, the endogenous downregulation of the APJ receptor results in benefits from the exogenous administration of apelin.

This paper comprehensively describes the development process, existing problems and future solutions of wheat straw and rice straw cement-based building materials in China. Straw cement-based building materials are environmentally friendly and have excellent thermal insulation, impact resistance, as well as social and economic benefits. In this paper, straw cement-based building materials are divided into mechanical and composite-type building materials; previously, composite-type materials have mainly been studied. As the percentage of straw increases, the compressive strength of these materials decreases; therefore, composite-type building materials with a straw content of no greater than 5% can be used for non-load-bearing structures. These materials have problems such as difficulty in stirring and slow hardening during preparation. Modification treatments can improve the compressive strength and flexural strength, but these processes often result in energy consumption and environmental pollution. For the two types of straw building materials, additional research is needed to determine the relationship between the mechanical properties and the microstructure and failure mechanism. A new concept of a mechanical bionic straw material is proposed that can overcome the above problems, suggesting the possible development of a new type of bionic light straw building material.