Effect Of Different Intermittent Hypoxia Patterns Of Sleep Apnea Model On Superoxide Dismutase And Malondialdehyde

Objective To investigate the effect of degree and frequency of intermittent hypoxia of obstructive sleep apnea syndrome(OSAS) on the levels of superoxide dismutase(SOD) and malondialdehyde(MDA). To provide experimental data and theory evidence for studying sleep apnea and its cardia and Cerebral vessels complication.Method The experiment was divided to two parts.The first part:Human umbilical vein endothelial cells of the line ECV304 were used to set up the cells model. The experiment cell strains contained one control group and eight experimental groups.1 constance normoxia group (control group),3 different intermittent hypoxia(IH) degree groups (10%O2 group,1.5%O2 group,0.5% O2 group with 12time/h),5 different intermittent hypoxia(IH) frequency groups(40time/h,20time/h,12time/h,9.23time/h and 6.32time/h with 1.5%O2) to each IH degree group. They were putted into a program-controlled gas delivery system with different level and frequency of IH respectively. Then Enzyme Linked Immuno Sorbent Assay (ELISA) was used to examine the levels of superoxide dismutase(SOD) and malondialdehyde(MDA).The second part:All cases were collected by monitoring of polysomnography (PSG). The groups contained one control group (group A) and four experimental groups. Four experimental groups contained mild OSAS (group B), moderate OSAS (group C), severe OSAS (group D) and severe OSAS with hypertension (group E). To record the Apnea Hyponea Index(AHI) and Lowest Oxygen Saturation (LSO2)of all OSAS patients. In the morning of finishing PSG, blood specimens were collected in all groups and then ELISA was used to examine the levels of SOD and MDA in serum.Results:The first part:â‘ The level of MDA of three different degree intermittent hypoxia groups were higher than the level in the control group (P<0.01).The level of SOD in three different degree hypoxia groups is lower than the level in the group (P<0.01).The level of SOD was decreased and the level of MDA was increased gradually with the decreasing of hypoxia degree (P<0.01).â‘¡There is a trend as the level of MDA and SOD increased and decreased with frequency decreased. The level of MDA was no different between the group of frequency in 40/ hour and 20/hour (P>0.05). When hypoxia frequency decreased, the level of MDA increased, and the level of 9.2 per hour exposure group was the lowest, but the level of MDA decreased again when the frequency was reaching 6.3 per hour (P<0.01). When hypoxia frequency decreased, the level of SOD decreased, and the level of 9.2 per hour group was the highest, but the level of SOD decreased again if the hypoxia frequency was reaching 6.3 per hour (P<0.01).â‘¢The level of SOD was negative correlated to that of MDA under different hypoxia degree exposure (r=0.932, P=0.000),and the level of SOD was negative correlated to that of MDA under different frequency exposure (r=0.832, P=0.000).The second part:â‘ ontrasted with control group, the level of SOD in different OSAS groups were all lower (P<0.05),and the level of MDA in defferent OSAS groups were all higher (P<0.05).There was statistical significance between each two different OSAS groups on the level of SOD amd MDA(P<0.05).As the degree of OSAS increased, the level of SOD decreased,and the level of MDA increased.â‘¡Lower level of SOD and higher level of MDA was found in severe OSAS with hypertension group than in severe OSAS group(P<0.05).â‘¢nder different degree OSAS groups, the level of SOD was negative correlated to that of MDA(r=-0.857.P<0.01),the level of SOD was negative correlated to that of AHI(r=-0.914.P<0.01) and positive correlated to that of LSO2(r=0.752,P<0.01),the level of MDA was positive correlated to that of AHI(P=0.921.P<0.01) and was negative correlated to that of LSO2(r=-0.864,P<0.01).Conclusion:Intermittent Hypoxia of OSAS caused oxidative stress reaction and that induces the increasing of reactive oxygen species(ROS), and the antioxygen capacity become weaker. The decreasing and increasing of oxidative stress reaction depends on the degree of hypoxia. There was a trend as the level of IH frequency decreased, reactive oxygen species increased at first gradually and then decreased,the antioxygen capacity decreased at first gradually and then increased. The degree of oxidative stress reaction increased was not always with IH frequency increased. Exposed to intermittent hypoxia, the balance of oxidative stress reaction and antioxygenative system of endothelial cell was disturbed. As the degree of OSAS increased, oxidative damage of organism increased and the antioxygen capacity decreased. Oxidative stress reaction of OSAS was intimate correlated to the degree of OSAS. Oxidative stress reaction becomes stronger and antioxygen capacity becomes weaker in OSAS with hypertension. Oxidative stress reaction of OSAS maybe act important role in hypertension development of OSAS.