ABSTRACT
In order to investigate the influence of silencing soluble epoxide hydrolase (sEH) with double-stranded small interfering RNA (siRNA) on cardiomyocytes apoptosis induced by doxorubicin (DOX),two plasmids containing siRNA sequences specific to sEH were constructed and transfected into the primary cultured cardiomyocytes by using FuGENE HD transfection agents.The mRNA and protein expression levels of sEH were detected by semiquantitative RT-PCR and Western blotting respectively,and the plasmids that silenced sEH most significantly were selected,and renamed EH-R.The plasmids carrying a nonspecific siRNA coding sequence (PCN) served as the negative control.Cardiomyocytes were divided into four groups:control group,DOX group,PCN+DOX group,and EH-R+DOX group.Apoptosis of cardiomyocytes was induced by DOX at a concentration of l μmol/L.Apoptosis rate of cardiomyocytes was determined by flow cytometery.The protein expression levels of Bcl-2 and Bax were detected by Western blotting.The results showed that the expression of sEH was down-regulated by EH-R plasmid.The expression levels of sEH mRNA and protein in the EH-R+DOX group were significantly decreased as compared with other groups (P＜0.01).As compared with the control group,the apoptosis rate of cardiomyocytes in three DOX-treated groups was obviously increased,the expression levels of Bax increased,and those of Bcl-2 decreased (P＜0.01).However,the expression levels of Bax were decreased,those of Bcl-2 increased and the apoptosis rate of cardiomyocytes obviously decreased in EH-R+DOX group when compared with those in the DOX group and the PCN+DOX group (P＜0.01 for each).It was concluded that the recombinant plasmids could be successfully constructed,and transfected into the primary cultured cardiomyocytes.They could ameliorate the DOX-induced cardiomyocytes apoptosis by selectively inhibiting the expression of sEH with RNAi and increasing the expression of Bcl-2.
ABSTRACT
This study examined the role of high-sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6) and cystatin C in ischemic stroke complicating atrial fibrillation (AF) and the relationship of systemic inflammation with this disease in order to identify AF patients who are at high risk of stroke and need optimal anticoagulant therapy. A total of 103 AF patients, simple (n=75) or complicated by ischemic stroke (n=28), and 112 control subjects were recruited. IL-6 level was detected by using enzyme linked immunosorbent assay. Cystatin C and hsCRP levels were measured by means of a particle-enhanced immunonephelometric assay. The results showed that the AF patients had higher levels of hsCRP (P=0.004), IL-6 (P=0.000), and cystatin C (P=0.000) than control subjects. Plasma hsCRP level was increased in the AF patients with ischemic stroke as compared to the patients with simple AF (P=0.036). The AF patients who had the level of hsCRP exceeding 3.83 mg/L were at a higher risk than those with hsCRP level lower than 3.83 mg/L (P=0.030). After adjusting for other factors,cystatin C remained positively associated with IL-6 (r=0.613) and hsCRP (r=0.488). It was concluded that hsCRP is positively correlated with ischemic stroke complicating AF and may be a risk factor independent of other risk factors for AF. Elevated cystatin C level is also indicative of the increased risk of AF.
ABSTRACT
Summary: The aim of this study was to determine if the potassium aspartate and magnesium (PAM) prevent reperfusion-induced ventricular arrhythmias (RIVA) in ischcmia-reperfusion (IR) rabbit heart. Thirty rabbits were randomly divided into control, ischemia and PAM groups. Arterially-perfused rabbit left ventricular preparations were made, and transmural ECG as well as action potentials from both endocardium and epicardium were simultaneously recorded in the whole process of all experiments. In control group rabbit ventricular wedge preparations were continuously perfused with Tyrode's solution, and in ischemia group and PAM groups the perfusion of Tyrode's solution was stopped for 30 min. Then the ischemia group was reperfused with Tyrode's solution and the PAM group with Tyrode's solution containing 2.42 mg/L PAM, respectively. ECG, QT interval, transmural repolarization dispersion (TDR) and action potentials from epicardium and endocardium were simultaneously recorded, and the RIVA of the wedge preparation was observed. Compared with control group, TDR and incidence of RIVA were significantly increased in ischemia group (P<0.05). The incidence of RIVA in control, ischemia and PAM group was 0/10, 9/10 and 1/10, respectively. Compared with ischemia group, TDR and incidence of RIVA were significantly reduced in PAM group (P<0.05). Potassium aspartate and magnesium significantly reduce TDR and prevent ventricular arrhythmia in ischemic rabbit heart.