Dual-modular immunosensor for bongkrekic acid detection using specific monoclonal antibody.

Bongkrekic acid (BA) is a mitochondrial toxin that causes high mortality but is often mistakenly categorized as other food poisonings. The immunoassay of BA is still challenging since the specific antibody is unavailable. In this work, a monoclonal antibody specific to BA was first generated and a dual-modular immunosensor for on-site and laboratory detection was established. The antibody showed good affinity (Kd=0.33 µM) and sensitivity (IC50 =17.9 ng/mL in ELISA) with negligible cross-reactivity with common mycotoxins. In dual-modular conditions, fluorescence assay (FA) was conducted based on the inner filter effect of carbon dots (CDs) and oxidized 3,3',5,5'-tetramethylbenzidine (TMB), while the colorimetric assay (CA) was conducted using TMB2+-mediated rapid surface etching of gold nanostars (Au NSs). The proposed immunosensor showed good sensitivity and reproducibility to BA in food samples, with a limit of detection lower than 10 ng/mL and recovery ranging from 80.0% to 103.6%, which was in good consistence with that of standard LC-MS/MS. Overall, the proposed immunosensor is an ideal tool for screening BA contaminants in food with good sensitivity and high effectivity.

[Protective effect and mechanism of curcumin on aorta in rats with metabolic syndrome].

To investigate the protective effect and mechanism of curcumin on aorta in rats with metabolic syndrome,72 SD rats were randomly divided into blank control group,model control group,positive control group,curcumin low,middle and high dose groups.The rat model of metabolic syndrome was established in all groups except the blank control group. After the intervention by curcumin,the blood pressure,blood lipid,blood glucose,serum insulin and insulin sensitivity index were measured. The contents of serum leptin(LP),adiponectin(ADP) and tumor necrosis factor-α(TNF-α) in rat aorta were detected by enzyme-linked immunosorbent assay(ELISA),and the pathological changes of rat thoracic aorta were observed by HE staining and electron microscope scanning. Western blot assay was used to detect the expression of inducible nitric oxide synthase(i NOS) and endothelial nitric oxide synthase(e NOS) in rats. The results showed that the blood lipid level,fasting blood glucose,fasting insulin,insulin sensitivity index,systolic blood pressure,LP,TNF-α and intima/media thickness ratio in the model control group were significantly higher than those in the blank control group. As compared with the model control group,the levels of blood lipids,fasting blood glucose,fasting insulin,insulin sensitivity index,systolic blood pressure,LP,TNF-α and intima/media thickness ratio were significantly decreased in positive control group,low,middle and high dose curcumin groups. The difference was statistically significant. The results of HE staining showed that the intima of the thoracic aorta in the model group was significantly thickened; the endothelial cell membrane was wrinkled and the organelle was ruptured. The intima of the thoracic aorta in the positive control group was slightly thickened and the structure of endothelial cells was intact,with no foam cells and no abnormality in the adventitia. There was no significant thickening of the thoracic aorta in the low,middle and high dose curcumin groups,and the endothelial cells were still intact. The results of Western blot assay showed that the expression levels of i NOS and e NOS were decreased significantly in the model group,while the expression levels of i NOS and e NOS were increased significantly in the positive control group and curcumin groups. The results indicated that curcumin had a certain protective effect on the aorta of rats with metabolic syndrome and improves the aortic endothelial dysfunction,and its mechanism may be related to the fact that curcumin could reduce the production of oxygen free radicals and up-regulate the expression of i NOS and e NOS in aorta.

Sulforaphane prevents rat cardiomyocytes from hypoxia/reoxygenation injury in vitro via activating SIRT1 and subsequently inhibiting ER stress.

AIM: Sulforaphane (SFN), a natural dietary isothiocyanate, is found to exert beneficial effects for cardiovascular diseases. This study aimed to investigate the mechanisms underlying the protective effects of SFN in a model of myocardial hypoxia/reoxygenation (H/R) injury in vitro. METHODS: Cultured neonatal rat cardiomyocytes pretreated with SFN were subjected to 3-h hypoxia followed by 3-h reoxygenation. Cell viability and apoptosis were detected. Caspase-3 activity and mitochondrial membrane potential (ΔΨm) was measured. The expression of ER stress-related apoptotic proteins were analyzed with Western blot analyses. Silent information regulator 1 (SIRT1) activity was determined with SIRT1 deacetylase fluorometric assay kit. RESULTS: SFN (0.1-5 µmol/L) dose-dependently improved the viability of cardiomyocytes, diminished apoptotic cells and suppressed caspase-3 activity. Meanwhile, SFN significantly alleviated the damage of ΔΨm and decreased the expression of ER stress-related apoptosis proteins (GRP78, CHOP and caspase-12), elevating the expression of SIRT1 and Bcl-2/Bax ratio in the cardiomyocytes. Co-treatment of the cardiomyocytes with the SIRT1-specific inhibitor Ex-527 (1 µmol/L) blocked the SFN-induced cardioprotective effects. CONCLUSION: SFN prevents cardiomyocytes from H/R injury in vitro most likely via activating SIRT1 pathway and subsequently inhibiting the ER stress-dependent apoptosis.

[Experimental study of electroacupuncture improving the obstruction of vestibular microcirculation in vertebrobasilar insufficiency and the effect on vestibulo-ocular reflex].

AIM: To investigate the mechanism of EA improving the obstruction of inner ear microcirculation and the effect on the vestibulo-ocular reflex (VOR) by comparing the effects of electroacupuncture (EA) with sibelium (flunarizine hydrochloride) on vertebrobasilar insufficiency(VBI). METHODS: Injected with sclerosant-775 injection into the solt tissue on the left side of cervical vertebral transverse processes of rabbits to set up the vertebral artery type of cervical spondylosis (VCS) models. Electronystagmography (ENG) induced by linear acceleration (LA) and horizontal rotation (HR), the transcranial Doppler (TCD), laser Doppler flowmetry (LDF) and hemorheology were used to measure changes of the frequencies of nystagmus, the hemodynamics in the basilar artery (BA), inner ear blood flow(IEBF) and blood viscosity in VBI rabbits. RESULTS: The frequencies of ENG, the velocity of blood flow in BA and IEBF decreased obviously, and whole blood middle where viscosity, whole blood lower where viscosity and erythrocyte distortion index ( EDI) increased significantly in the model group. Sibelium could reduce whole blood viscosity and EDI, and increased the systolic phase velocity (Vs) of blood flow in BA, but had no effect on diastolic phase velocity (Vd) and mean velocity (Vm). EA could not reduce the viscosity of blood and EDI, but had more significant effects on improving IEBF and ENG induced by LA than those of sibelium,and had the tendency of increasing Vs, Vd and Vm. EA and sibelium had no effect on improving ENG induced by HR. CONCLUSION: Inner ear microcirculation obstruction caused by VBI can induce dysfunctions of vestibule cyst macula and horizontal semicircular canals. EA may depend upon the neurohumoral regulation to improve VBI, and ameliorate inner ear blood supply obstruction by enhancing mechanism of local adjusting for microcirculation in the inner ear to recover vestibular cyst macula irritability for LA chiefly. There exist complicated mechanism that EA adjusts blood flow distribution and vestibular signal transduction in vestibular organ in VBI model likely, and remain to be researched deeply.