| BACKGROUND AND OBJECTIVEHigh density lipoprotein (HDL) plays an very important role in anti-atherosclerosis by promotion of reverse cholesterol transport (RCT), anti-inflammation and anti-oxidation. In clinical work, HDL-cholesterol complex (HDL-C) is tested to estimate the level of HDL in circulation. The fact that level of HDL-C is a negative risk factor for coronary heart disease (CHD) has been discovered for a long time. So raising the level of HDL-C is now one of the main targets of anti-atherosclerosis therapy. However, recent researches indicate that the function of HDL will decrease or even reverse under some special conditions such as acute stress or chronic inflammation. It is now universally realized that the function of HDL is as important as, or more important than the quantity.Oxidation of lipids is the core event of the starting of atherosclerosis. It causes the formation of atherosclerosis plaque by inducing the generation and apoptosis of the foam cells. Cigarette smoking is an independent risk factor for prediction of atherosclerosis. Many researches indicate that smoking can raise the level of LDL-cholesterol complex (LDL-C) and reduce the level of HDL-C simultaneously. Smoking cessation can reverse this kind of change. But the continual variation of the function of HDL in the process of smoking remains unkown. The objective of our research is to determine whether and how the anti-oxidation function of HDL varies in healthy candidates during the acute phase and chronic phase of smoking, and to find out the mechanism of that variation if it exists.METHODS1.42healthy candidates were enrolled, including20non-smokers and22chronic smokers. Plasma sample were collected and divided into4groups:non-smokers before smoking, on-smokers after smoking, smokers before smoking, and smokers after smoking.2. Lipoprotein was isolated by ultracentrifugation from plasma samples, the concentration of lipoprotein was tested by BCA kit and the purity was identified by agarose gel electrophoresis.3. The concentration of Serum Amyloid Protein A (SAA) on HDL was tested by ELISA kit.4. PON-1activity was tested by fluorometric kit. 5. The oxidation baseline and susceptibility of LDL to oxidation was tested by ultraviolet absorption spectrometry (wavelength=234nm). The baseline was estimated by basic optical density (OD). The susceptibility was estimated by time at maximal ascending velocity (time at Vmax) of the OD-t curve after copper ion added; and the final oxidation level was estimated by maximal OD (ODmax).6. LDL of non-smokers before smoking was mixed to make LDL in normal state (LDLpooi). The anti-oxidation ability of HDL was also tested by ultraviolet absorption spectrometry (wavelength=234nm). The oxidation baseline of HDL was estimated by basic OD. Then HDL was mixed with LDLpool and copper ion was added. The anti-oxdation abilty was estimated by lagging time (Tlag) and t at Vmax of the OD-t curve.RESULT1. Pluse rate (P) is higher after smoking in both non-smokers and chronic smokers (67.2±13.4vs71.5±9.9, p<0.05;74.8±10.5vs78.4±9.2, p<0.05), systolic blood pressure (SBP) obviously higher (116.2±13.4vs119.8±13.3, p<0.01;123.4±2.8vs126.2±3.9, p<0.01), diastolic blood pressure (DBP) obviously higher (71.0±8.9vs76.8±10.0, p<0.01;70.8±8.0vs74.2±7.5,<0.01).2. Bilirubin of chronic smokers is lower than non-smokers, whatever the value before or after smoking (TBil:15.15±5.42vs10.80±4.05, p<0.01,14.37±7.05vs10.80±4.05, p<0.05; DBil:5.07±2.20vs3.53±1.21, p<0.01,4.84±2.59vs3.53±1.21, p<0.05).3. Uric acid (UA) is higher after smoking in chronic smokers (273.7±56.9vs323.8±49.4, p<0.05).4. Serum amyloid A (SAA) is obviously higher after smoking in non-smokers (10.07±4.37vs15.83±8.50, p<0.01), SAA is lower in chronic smokers than non-smokers after smoking (15.83±8.50vs9.66±3.76, p<0.01).5. Basic OD of LDL of chronic smokers is higher than non-smokers, whatever the value before or after smoking (0.209±0.025vs0.276±0.054, p<0.01;0.217±0.052vs0.276±0.054, p<0.01).6. T at Vmax of LDL of chronic smokers is lower than non-smokers, whatever the value before or after smoking (52.5±15.2vs45.0±8.7, p<0.05;53.9±14.9vs45.0±8.7, p<0.01); ODmax is higher after smoking in chronic smokers (0.580±0.162vs0.707±0.118, p<0.05).7. Tlag of mixed lipoprotein is lower after smoking in both non-smokers and chronic smokers (96.0±14.4vs88.5±10.8, p<0.05;106.0±15.6vs89.4±20.3, p<0.05). Tlag of chronic smokers is higher than non-smokers, whatever the value before or after smoking (96.0±14.4vs106.0±15.6, p<0.05;89.4±20.3vs106.0±15.6, p<0.01). The margin (descending) in chronic smokers is larger than in non-smokers.8. T at Vmax of mixed lipoprotein of chronic smokers is higher than non-smokers, whatever the value before or after smoking (135.5±16.7vs145.4±14.0, p<0.05;128.1±17.7vs145.4±14.0, p<0.01).CONCLUSIONS1. Organism is under an acute stress strike after once-smoking2. Organism is under a chronic oxidation state after long-time uptake of tobacco smoke. There is an exhaustion of inner anti-oxidant such as bilirubin during long-time oxidation pressure.3. After once-smoking, the anti-oxidation ability of HDL decreases.4. The anti-oxidation ability of HDL increases in chronic smokers, which is a possible compensative mechanism of organism. But it can not correct the chronic oxidation state by long-time cigarette smoking.5. The anti-oxidation ability of HDL in chronic smokers performs a more obvious descending when organism is encountering an acute stress strike. |
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