Correlation Between NADPH Oxidase In Peripheral Blood Mononuclear Cells And Carotid Intima-media Thickness In Elderly Men

BackgroundThe oxidation hypothesis has received much attention and suggests that the oxidation of LDL within the vessel wall plays a key role in the development of the atherosclerosis. Oxidized LDL is capable of initiating processes that contribute to the formation of atherosclerotic lesions. For example,it is the oxidized form of LDL that is taken up by macrophages and up-regulate expression of cellular adhesion molecules and stimulate smooth muscle cell proliferation. Finally, oxidized LDL can pose an oxidant stress that injures vascular smooth muscle and endothelial cells.Pathological conditions that predispose to cardiovascular events, such as hypertension, hypercholesterolemia ,and diabetes, are associated with oxidative stress. Data from numerous studies provided accumulating evidence that oxidative stress is decisively involved in the pathogenesis of endothelial dysfunction and atherosclerosis. Reactive oxygen species(ROS) have emerged as important molecules in cardiovascular function. Overproduction of ROS under pathophysiology condition is integral in the development of cardiovascular disease . In addition to mediating LDL oxidation,ROS may contribute to the pathogenesis of atherosclerosis in a variety of other ways. Among these, the ROS induces stress responses that alter cell function, including adhesion, proliferation, and motility.Several enzymes expressed in vascular tissue contribute to production and efficient degradation of reactive oxygen species. Recent work has shown that ROS of human vascular system mostly derive from NADPH oxidase.ROS produced by NADPH oxidase can interact with proteins, lipids, and DNA, cause oxidative stress and some pathophysiology changes .Cross-sectional observational studies have demonstrated an inverse relationship between endogenous serum testosterone (T) levels and atherosclerosis in males. oxidative stress is one of the mechanisms of atherosclerosis. However, no study investigated the relationship between endogenous sex hormone levels and oxidative stress.ObjectiveTo investigate the relation between carotid artery disease and the oxidative stress condition , the expression of NADPH oxidase.To get the message between endogenous testosterone and NADPH oxidase.Methods1.Detected the expression of the subunits of NADPH oxidases in MNC by PCR;2.Measured the production of ROS by flow cytometry with LDL stimulation and the inhibitor of the oxidant enzymes.;3.Thirty-two patients with IMT≥0.9 mm (higher group)and 28 control with IMT< 0.9 mm(normal group).All people were drawm fasting blood to measure biochemical markers.;4.Measured lipid peroxidation ( represented by MDA) and oxidative injury of protein (represented by protein carbaroxylaton) in serum to get an overall information of oxidative stress state of all the subjects;5.Compared the expression of the subunits of NADPH oxidases 2 on MNC between higher group and normal control by Realtime-PCR and Western blot ;6.Compared the localization of p47phox between higher group and normal control. Finally, we analyzed the clinical index, oxidative stress index and expression of NADPH oxidase by SPSS.Results1.Between two groups, age,TC, HDL-C are not significantly different. The levels of the testosterone,Hs-CRP,Uric acid,FBS,TG and LDL were significantly higher in higher group than control group,(P <0.05);2.The levels of MDA were significantly higher in higher group than control group, 6.36±3.2 (nmol/ml) versus 4.95±2.63 (nmol/ml()P <0.05). The levels of carbonyl protein also were also higher in higher group group(P<0.05);3.The expression of NOX2 on NMC mRNA was higher in higher group group than control group, 1.89±0.76 versus 1.49±0.59,P =0.038.While no significant difference was observed in other subunits. These results were further confirmed by Western blot.;4. The p47phox is highly activated on NMC in higher group , the activation rate is 30.56% in higher group and 18.70% in control group;5.Significant inverse correlation between testosterone levels and NOX2 expression level or MDA level was found in test subjects. Conclusions1.The higher levels of oxidative stress condition is one of the important mechanisms to promote atherosclerosis;2.The NADPH oxidase participate in adjust oxidative stress condition through the expression of NOX2 and the actiation of p47phox;3.The levels of testosterone has some associativity with oxidative stress and atherosclerosis.