3D nanocake-like Au-MXene/Au pallet structure-based label-free electrochemical aptasensor for paraquat determination.

3D nanocake-like Au-MXene and Au pallet (Au-MXene/AuP) nanocomposite-modified screen-printed carbon electrodes (SPCEs) were utilized to construct an ultrasensitive label-free electrochemical aptasensor through a self-assembly procedure for trace paraquat (PQ) residue detection. Benefiting from the excellent electrochemical (EC) performances (e.g., high conductivity and large surface area) of Au-MXene nanocomposites and AuP substrate, the developed Apt/Au-MXene/AuP/SPCE-based EC aptasensor displayed excellent specificity and anti-interference ability, good repeatability, and stability. A linear relationship between the log value of the change in current intensity [lg (ΔI)] and the log value of the concentration of PQ [lg (CPQ)] was obtained in the range 0.05-1000 ng/mL. The limit of detection was 0.028 ng/mL, and the sensitivity was 255.5 µA/(µM·cm2). Practical applications in malt and mint samples confirmed the accuracy of the EC aptasensor in complex matrices for PQ detection, providing a universal analytical tool for other trace pesticides in different food samples by simply replacing the corresponding aptamers.

[Protective effect of oxymatrine on chronic heart failure and ADMA metabolism pathway in isoproterenol-induced chronic heart failure in rats].

OBJECTIVE: To investigate the protective effects of oxymatrine on chronic heart failure induced by isoproterenol (ISO) and to observe its effects on ADMA metabolism pathway in ISO-induced chronic heart failure in rats. METHOD: Male Sprague-Dawley rats were given oxymatrine (100,50 mg kg-1) orally for 14 days. Heart failure was induced in rats by subcutaneous injection of isoproterenol (5 mg kg-1 d-1 ) at the 8th day for 1 week. Serum parameters, haemodynamic parameters, Heart weight, and histopathological variables were analysed. Expression of protein levels were measured by Western blot. RESULT: Oxymatrine (100,50 mg kg-1) significantly attenuated serum content of cTn I, improved left ventricle systolic and diastolic function and left ventricular remodeling, reduced the ISO-induced myocardial pathological changes compared with ISO group. In addition, oxymatrine (100,50 mg kg-1) significantly reduced serum level of ADMA (P <0. 01), normalize the reduced dimethylarginine dimethylaminohydrolase 2 (DDAH2) expression (P <0. 01) , but had no effect on the isoproterenol-induced upregulated protein arginine methyltransferases 1 expression. CONCLUSION: Oxymatrine could ameliorate the experimental ventricular remodeling in ISO-induced chronic heart failure in rats and the mechanism involved in reducing serum content of ADMA and increased DDAH2 expression.

Protective Effects of 18ß-Glycyrrhetinic Acid on Monocrotaline-Induced Pulmonary Arterial Hypertension in Rats.

Pulmonary arterial hypertension (PAH) is a destructive and rare disorder characterized by a progressive increase in pulmonary artery pressure and vasoconstriction, ultimately leading to right ventricular failure and death. 18ß-Glycyrrhetinic acid (18ß-GA) is an active ingredient in the commonly used Chinese herbal medicine radix glycyrrhizae, and it possesses antioxidant, anti-inflammatory, anti-tumor, and other pharmacological properties. This study aimed to determine whether 18ß-GA has protective effects against monocrotaline (MCT)-induced PAH and whether it is associated with oxidative stress. The PAH of rats was induced by MCT (60 mg/kg) and oral administration of 18ß-GA (100, 50, or 25 mg/kg/day), sildenafil (30 mg/kg), or saline for 21 consecutive days. The development of PAH was evaluated by hemodynamic parameters and right ventricular hypertrophy index. Hematoxylin and eosin staining, Masson trichrome staining, and electron microscopy were used to determine the degree of vascular remodeling and proliferation in lung tissue. Moreover, the antioxidant capacity and malondialdehyde levels in the lungs were measured according to the instructions provided by the test kits, and the expression levels of nicotinamide adenine dinucleotide phosphate oxidase-2 (Nox2) and Nox4 were detected through Western blot analysis. Results of our study indicated that 18ß-GA treatment significantly improved the hemodynamic and pathomorphological data of the rats, reduced the changes in oxidative stress biomarkers, and inhibited Nox2 and Nox4 expression. Our research indicated that 18ß-GA has a protective effect against MCT-induced PAH by inhibiting oxidative stress in rats.