Abstract:Aim To detect the anti-oxidation efficiency of vitamin E in different low density lipoprotein （LDL） oxidation models and explore the possible reasons for low antioxidant efficiency of vitamin E. Methods The active LDL oxidation model and passive LDL oxidation model were established in CLR-1730 cell line respectively. After the co-stimulation with LDL and VE for 0 h, 12 h, and co-stimulation with LPS and VE for 0 h,3 h, the mRNA and protein expression levels of human alpha-defensin-1（HNP-1）were detected by using real time PCR and ELISA. We set up 3 different VE working groups: VE added before the oxidation model（pre-VE）,vitamin E added after oxidation model（post-VE） and the control［VE（－）］. We detected malondialde （MDA）, protein carbonyl （PCO） and super oxide dlsmutase （SOD） to determine whether vitamin E interfere with the oxidation model. The level of oxygen free radicals in cells were observed by using flow cytometry and fluorescence microscopy . Results （1） The mRNA levels and protein levels of HNP-1 were increased in oxidation models （P<0.05）. （2） PCO detection among the three groups in active model showed no significant difference （P>0.05） while in passive model the pre-VE and post-VE results were significantly lower than the VE（－） （P<0.05）. PCO detection: the difference during pre-VE and post-VE in active model was not obvious, but both were significantly lower than the VE（－） （P<0.05）. SOD detection: pre-VE in active model was significantly higher than post-VE and VE（－）（P<0.05）. （3） In both oxidation models, the intracellular oxygen free radicals in the pre-VE and post-VE groups were higher than the control. Conclusion VE would not affect the establish-ment of active and passive oxidation models. The antioxidant efficiency of anti-lipid and protein oxidation is significantly different, while the activity of SOD were enhanced in both models.

Abstract:AimTo investigate the effects of advanced glycation end products(AGE) and homocystein（Hcy）on the expression of vascular cell adhesion molecule-1(VCAM-1) mRNA via oxidative stress mechanism in human umbilical vein endothelial cell（HUVEC）.MethodsCollagenase was used to isolate the endothelial cell from human umbilical vein.RT-PCR was used to examine the expression of VCAM-1 mRNA.Inversion fluoescence microscope was used to observe the level of oxygen free radical.Results The expression of VCAM-1 mRNA was induced concentration-dependently by AGE(10－4～10－1 g/L) and Hcy(1.35×10－3～1.35 g/L); AGE combined with Hcy group could promote the expression of VCAM-1 mRNA respectively 7.78 times and 6.05 times in comparison with AGE group and Hcy group（1.09±0.18 vs 0.14±0.07；1.09±0.18 vs 0.18±0.06， P<0.01）; By comparison with AGE combined with Hcy group, the VCAM-1 expression of DPI group was obviously reduced(0.20±0.09 vs 1.19±0.23,P<0.01); In comparison with control group, AGE group and Hcy group could enhance oxygen free radical in HUVEC; The level of oxygen free radical in AGE combined with Hcy group was higher than that in AGE group and Hcy group; DPI could significantly inhibit the level of oxygen free radical.ConclusionAGE and Hcy can enhance the level of oxygen free radical in HUVEC and increase the VCAM-1 expression, and they have the cooperative effect; The enhancement of oxygen free radical is an important factor on the expression of VCAM-1 mRNA; The above process is realized possibly through activating the NADPH oxidase.

Abstract:Aim To investigate the electrocardiographic features and its possible mechanisms at the moment of myocardial ischaemia and reperfusion injury (IRI) in patients with acute ST segment elevation myocardial infarction (STEMI). Methods The electrocardiographic changes during reperfusion of acute STEMI by thrombolysis or percutaneous coronary intervention (PCI) were analysed. Effective data of IRI electrocardiographic pattern were explored with univariate analysis. 60 cases of acute STEMI were classified into myocardial reperfusion with IRI electrocardiographic changes group (reperfusion group A,n=39) and without IRI electrocardiographic changes group (reperfusion group B,n=21). The levels of serum reactive oxygen species (ROS),malondialdehyde (MDA),reduced glutathione (GSH),total antioxidative capacity (T-AOC) and γ-glutamylcysteine synthatase (γ-GCS ) activity were measured in control group (n=43),myocardial ischaemia group (before reperfusion therapy,n=60),reperfusion group A and reperfusion group B. Results Among the 60 cases of acute STEMI,39 patients (65.00%) with IRI arrhythmia (accelerated idioventricular rhythm 26.67%,non-paroxysmal ventricular tachycardia 10.00%,sinus bradycardia 10.00%,and atrioventricular nodol block 8.33%)as well as 28 patients (46. 67%) with IRI ST segment elevation were observed. Univariate analysis revealed that the duration from chest pain to receiving reperfusion therapy,the peak time of CK-MB ,and reperfusion time were shorter in the reperfusion group B than those in the reperfusion group A (P><0.05). The more IRI electrocardiographic changes were detected during reperfusion treated by thrombolysis than by PCI (P><0.05). The levels of serum ROS and MDA in the reperfusion group A were significantly higher,but the GSH and T-AOC were significantly lower than those in the control group,myocardial ischaemia group,and reperfusion group B (P><0.05). The γ-GCS activity in reperfusion group A was significantly higher than that in the control group and myocardial ischaemia group (P><0.05). Conclusion This study confirms the occurrence of specific electrocardiographic changes (IRI arrhythmia and ST segment elevation) at the time of reperfusion. Systemic oxygen free radicals oxidative/antioxidative imbalance occurs at the moment of reperfusion in patients with acute STEMI,which may correlate to IRI electrocardiographic changes.

Abstract:By means of cell counting and MTT assay, we observed that cultured bovine aortic smooth muscle cells (SMC) incubated with oxidized low density lipoprotein (OLDL, 0. 2 g protein·L-1 )for 12 hours and xanthine (X, 100 μmol·L-1) plus xanthine oxidase(XO, 100 U. L-1 ) for 2 hours showed multiplication of bovine aortic smooth muscle cells and that the effects of OLDL and X-XO were significantly inhibited by probucol. Synthesis inhibitor of nitric oxide (NO) NG-nitro-L-arginine(NG-L-Arg, 100 μmol· L-1) could not abolish the effect of probucol. Our data indicates that probucol could contend with multiplication of SMC induced by OLDL or X-XO.

Abstract:We investigated the effects of probucol on endothelial damage induced by exogenous free radicals and on activity of nitric oxide (NO).The results demonstrated that rabbit aortic rings incubated with xanthine(X,100 μmolL-1) and xanthine oxidase(XO,100 U·L-1) for 30min showed weak response to acetylcholine and that cultured bovine aortic endothelial cells incubated with X-XO for 30 min showed decrease of NO release and increase of malondialdehyde content.Probucol (40, 80 and 120 μmol·L-1) could protect endothelial cells from injury due to X-XO in a concentration-dependent menner, Inactivator of NO oxidized hemoglobin(OHb, 100μmol·L-1), not synthesis inhibitor of NO NG-nitro-L-arginie(NG-L-Arg,100 μmol·L-1), could abolish the effect of probucol. In the inhibitive experiment of NO synthesis and effect, we observed that the acetylcholine -induced relaxation ratio of aortic rings was reduced by NG-L-Arg, OHb and NO antagonist methylene blue(MB,100 μmol·L-1).Probucol 80 μmol·L-1 could contend with the relaxing inhibition of O Hb and MB not NG-L-Arg. Our data indicate that probucol can protect endothelial cells from damage due to free radicals. The mechanism of such protection may be partly associated with the maintenance of NO activity.

Abstract:This study was to investigated the effect of exogenous oxygen free radicals(OFR)on the rabbit basilar artery. Exogenous OFR were generated by electrolysis of Krebs solution. The perfusion pressure and malonyldialdehyde content in basilar artery were increased, meanwhile release of endothelium derived relaxing factor,nitrite content and superoxide dismutase activity decreased after OFR damage, These data indicated that OFR induced cerebral vasospasm is mainly mediated by cerebral vascular endothelial damage and lipid peroxide formation.