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OBJECTIVE：To investigate the effects of gypenosides （GPs）on gene expression of major urinary proteins （Mups） in liver tissue of hypercholesterolemia model mice. METHODS ：C57BL/6J mice were divided into control （ND）group，model （HFD）group and GPs therapy （GP）group according to body weight （BW），with 11 mice in each group. Except for ND group ， other groups were given high-lipid diet to induce hypercholesterolemia model. From the 17th week of feeding ，ND group and HFD group were given constant volume of 0.1％CMC-Na solution intragastrically ；GP group were given GPs suspension （250 mg/kg） intragastrically，once a day ，for consecutive 22 weeks. BW ，the levels of blood glucose （BG）and blood lipid （TC，LDL-C）were detected in each group. Total RNA of liver tissue was extracted ，and reverse transcription library was constructed and RNA-seq sequencing was performed. The differentially expressed genes were screened by PCA ，volcano map and scatter plot. RT-qPCR was used for verification for differentially expressed genes. The correlation between the expression of differentially expressed genes and the above pharmacodynamic indexes was analyzed by bivariate analysis. RESULTS ：Compared with ND group ，BW，the levels of BG，TC and LDL-C in HFD group were increased significantly （P＜0.05）. Compared with HFD group ，above indexes of GP group were decreased significantly except for BW （P＜0.05）. PCA showed that the data of ND group and HFD group distributed in different quadrants ，and the data distribution of GP group was between above two groups. mRNA of Mup4，Mup5，Mup11，Mup15 and Mup21 in liver tissue of mice were increased significantly after treated with high-fat diet （P＜0.05）. mRNA of Mup3，Mup4， Mup5，Mup8，Mup12 and Mup21 were decreased significantly after treated with GPs （P＜0.05）. In ND group vs. HFD group and HFD group vs. GP group ，mRNA of Mup4，Mup5 and Mup21 genes changed significantly and the trend was opposite. Results of RT-qPCR verification showed that compared with ND group ，relative mRNA expression of Mup4，Mup5 and Mup21 gene were increased significantly in HFD group （P＜0.05）. Correlation analysis revealed that mRNA expression of Mup5 was positively correlated with the levels of TC and BG （r＝0.727 1，0.670 6，P＜0.05），mRNA expression of Mup4 and Mup21 were positively correlated with the level of BG （r＝0.737 8，0.721 5，P＜0.05）. CONCLUSIONS ：GPs can regulate the expression of Mups genes in liver tissue of hypercholesterolemia model mice ， and reduce glucose and lipid level through regulating the mRNA over-expression of Mup4，Mup5 and Mup21.
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Objective: To study influence of acute hypoxia on the current of voltage-gated potassium channel (IK) in pulmonary artery smooth muscle cells (PASMC) of rats. Methods: A total of 20 male SD rats were randomly and equally divided into normoxic control group and acute hypoxia group. The rats in acute hypoxia group were kept in hypoxic chamber for 8 h before experiment. Whole cell patch-clamp technique was used to record IK in PASMC. Results: Acute hypoxia significantly decreased the IK density in PASMC of rats. During -60mV to -10mV of resting membrane potential（RMP）, acute hypoxia did not significantly decrease peak IK density in PASMC of rats, P>0.05; At 0 mV, acute hypoxia significantly decreased the peak IK density in PASMC [from（38.1 ± 5.2） pA / pF decreased to（9.82 ± 2.1） pA / pF ,P<0.05], then along with RMP increase in PASMC, the decreasing amplitude of peak IK density in PASMC gradually increased（P<0.05）; From + 30 mV to+ 60 mV, the decreasing amplitude of peak IK density in PASMC further significantly increased（P<0.01）; At + 60 mV the peak IK density decreased from（38.1 ± 5.2） pA / pF to（9.82 ± 2.1） pA / pF , and the decreasing amplitude reached (46.8±3.3)%. Conclusion: Acute hypoxia can decrease Kv current in PASMC of rats, leading to hypoxic pulmonary vasoconstriction.
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Autonomic nervous system activation can result in significant changes of atrial electrophysiology and facilitate induction of atrial fibrillation. By recording influence of different concentrations of acetylcholine (ACh) on atrial fibers (AF), we investigated the role of the increased vagal tone in electrical remodeling in atrial fibrillation. Parameters of action potentials and force contraction (Fc) in atrial fibers were recorded by using standard intracellular microelectrode technique and force transducer. It was found that: (1) ACh at 0.1 μmol/L had no significant influence on spontaneous action potentials (SAPs) and Fc (n=6, P>0.05); ACh at both 1.0 and 10.0 μmol/L shortened action potential duration (APD) and Fc of human AF from right atrium (n=6, P0.05), but ACh at 1.0 and 10.0 μmol/L had desensitization (n=6, P<0.05) to SAPs and Fc. The desensitization of ACh on APD in AF was concentration- and time-dependent. It was shown that APD was longer than the control along with extending time of continuous Tyrode's solution perfusion after desensitization. It is concluded that ACh changes the electrophysiological characteristics of human AF, indicating that increased vagal tone plays a role in the development of a vulnerable substrate for atrial electrical remodeling in atrial fibrillation.
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Objective To explore the effects of tumor necrosis factor-α (TNF-α) on ventricular arrhythmias resulted from acute myocardial infarction (AMI) in rats. Method Two hundred and forty male Wistar rats were randomized (random number) into sham operation group, AMI group and recombinant human tumor necrosis factor receptor (rhTNFR) fusion protein (Fc) group. Acute anterior wall myocardial infarction was produced in rats of AMI group with ligating the left anterior descending coronary artery (LAD) , and the rats were just operated without ligation of LAD in sham group. The rats of Fc group were treated with rhTNFR-Fc (10 mg/kg), a TNF-α antagonist, 24 hours before LAD ligation. The original ECG was recorded 10 min before ligation and the ECGs of ventricular arrhythmias occurred spontaneously or induced by programmed electrical stimulation were recorded 10 min, 20 min, 30 min, 60 min, 3 h, 6 h and 12 hours after ligation. The protein levels and mRNA expressions of TNF-α in rats in different groups were detected with histochemistry and real-time fluorescent quantitative PCR. Results The expressions of TNF-α mRNA and levels of TNF-α protein markedly increased 10 min after infarction, reached the climax 20-30 min later, and then gradually returned to the original level in AMI group and Fc group. The time-windows of spontaneous and induced ventricular arrhythmias were consistent with the time-window of expressions of TNF-α mRNA and levels of TNF-α protein. Compared with AMI group, there were lower levels of TNF-α protein and lower incidence of ventricular arrhythmias in Fc group ( P < 0.05) , but there was no significant difference in TNF-α mRNA between two groups. There was no obvious change in TNF-α in rats of sham operation group. Conclusions The expressions of TNF-α mRNA and levels of TNF-α protein induced by AMI could contribute the initiation of ventricular arrhythmias.
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L-homocysteic acid (HCA) and other amino acids were conjugated to rat brain material ( extracted rat brain protein) with glutaraldehyde to form HCA- and amino acids-brain material con-jugates. The specificity of monoclonal antibody (McAb) was tested on serial dilution test and ab-sorption test on enzyme- linked immunosorbent assay (ELISA) using these conjugates as antigens instead of amino acids-BSA (bovine serum albumin) conjugates used previously. The characterized McAb was applied for immunohistochemical staining using PAP (peroxidase antiperoxidase) tech-nique in combination with silver enhancement of diamino-benzene (DAB) products. The results in-dicated that McAb to L-HCA reacted with L-HCA-brain material conjugates, but not with other a-mino acids-brain material conjugates so far tested. McAb absorbed with L-HCA-brain material a-bolished or decreased immunoreactivity of L-HCA-brain material with McAb. The antibody selec-tively stained subpopulation of cells and processes in the hippocampus fixed with glutaradehyde. Absorption of McAb with L-HCA-brain material abolished immunohistochemical staining. These results suggested that McAb was specific for L-HCA-brain materials and could be used for imuno-histocytochemistry. This would provide a new tool for immunohistochemical visualization and locali-zation of L-HCA in the nervous system.
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AIM: To determine the effect of hydrogen peroxide(H_2O_2) on voltage-gated potassium channel currents(IKv) in pulmonary vascular smooth muscle cells(PASMCs).METHODS: Using whole cell patch-clamp technique,IKv was recorded in freshly isolated rat PASMCs with acute enzymatic digestion method.The effect of hydrogen peroxide on IKv in PASMCs was investigated in normoxia.RESULTS: IKv in PASMCs was increased significantly by H_2O_2 and the increase depended on the concentration in normoxia.Current-voltage relationship curve shifted to the left.CONCLUSION: Hydrogen peroxide is an important K~+ channel opener.
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AIM:To determine the role of Kv1 2, Kv1 5, Kv2 1 in the hypoxia pulmonary vasoconstriction (HPV). METHODS: Male Wistar rats were divided into two groups: normoxic group and hypoxic group. The single smooth muscle cell was obtained from pulmonary artery of Wistar rats with acute enzymatic digestion method. The conventional whole-cell patch clamp technique was used to record the resting membrane potential (Em) and the potassium currents of voltage-gated potassium channel (IKv) in rat pulmonary arterial smooth muscle cells (PASMC). Intracellular application of Kv1 2/Kv1 5/Kv2 1 antibodies (1∶125) was conducted through the whole-cell patch clamp system. RESULTS: ① Em of PASMC was depolarized after 24 h hypoxia compared with that of control cells [from (-51 8?0 8) mV to (-47 2? 0 7) mV, P
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AIM: To study the effect of adrenomedullin (ADM) on L-type calcium currents (I Ca,L) and its signaling transduction process in guinea-pig ventricular myocytes. METHODS: By using whole-cell patch clamp technique, the effect of ADM(1-100 nmol?L -1) on I Ca,Lmyocyte. Furthermore, the possible signaling transduction process of ADM on I Ca,L was investigated by observing the effects of ADM 22-52 (a specific ADM-receptor antagonist,100 nmol?L -1)+ADM(100 nmol?L -1), H-89 (a specific protein kinase A inhibitor, 10 ?mol?L -1) + ADM(100 nmol?L -1), PKC 19-36 (a specific protein kinase C inhibitor, 10 ?mol?L -1) + ADM(100 nmol?L -1) and PMA (a specific protein kinase C activator, 1 ?mol?L -1) on I Ca,L, respectively. RESULTS: ADM at the concentrations of 1-100 nmol?L -1 decreased I Ca,L in a dose-dependent manner (P