The Effect Of Chronic Intermittent Hypoxia On Oxidative Stress And Aorta Endothelial Cell In Rats

Objective：To make a chronic intermittent hypoxia (CIH) Sprague-Dawley（SD）rats model, as a stable and reliable experimental platform for the study ofthe Pathophysiology in sleep disorder breathing. To study the effects oforthobiosis environment, chronic intermittent hypoxia and removal ofhypoxia on oxidative stress system and aorta endothelial cell inSprague-Dawley rats, explore the possible mechanism of oxidative stresssystem disorder and the injury of aorta endothelial cell in patients with sleepdisorder breathing，and to provide a guidance for the clinical treatment ofpatients.Method：Twenty-four sex maturation rats were divided as random number intothree groups：unhandled control group (feeding for4weeks in normalenvironment, UC group), chronic intermittent hypoxia group (feeding for4weeks in chronic intermittent hypoxia cabin, CIH group), reoxygenationgroup(feeding for4weeks in normal environment after4weeks in CIH, RH group).Tested the activity of superoxide dismutase (SOD),malondialdehyde (MDA) and nitric oxide (NO) in blood serum of eachgroup after animal model accomplished. Killed rats by depletion method，dislodged rat’saortaforhematoxylinand eosin（HE）staining, observed theexpression of endothelial nitric oxide synthase (eNOS) byimmunohistochemisty.Results：1．Compared with UC group, the activities of SOD and NO weresignificantly lower in CIH group, but MDA was significantly higher. Thesedifferences were statistically significant (all of P<0.05respectively). Therewere no significantly differences in the weigh of MDA、SOD、NO betweenUC group and RH group (P>0.05).2．HE staining of the aorta: In light microscope the UC group showedaorta endothelial integrity, continuous, smooth and non-shedding ofendothelial cells；tunica intima，tunica media and tunica adventitia clear。Compared with UC group, in the CIH group, endothelial cells part off,aortic intima incomplete, partial smooth muscle cell of tunica media hyperproliferation，arrangement disorder, few smooth muscle cyrto to the tunicaintima. The aorta cells of RH group appeared similar to that of UC group inlight microscope, tunica intima cells full, smooth muscle elastic fibersarranged regularity, and no significant convex in the tunica media.3．Immunohistochemisty of the aorta: we found that brown granules were in aortic endothelialcell’s cytoplasm in UC group and RH group, dyewas lighter and brown granules was less in the endothelial of CIH group.Semi-quantitative analysis of immunohistochemical results: compared withUC group, the average gray level value was significantly below in CIHgroup (p<0.05), and there was no significant difference of average graylevel value between the UC group and RH group (p>0.05).Conclusion：1．Chronic intermittent hypoxia could activate the oxidative stresssystem， reoxygenation after hypoxia can make it back to normal levels.2．Chronic intermittent hypoxia could injure the aortal endothelialcell，and reduce the expression of nitric oxide synthase. Reoxygenationcould make the action of endothelial cell back to the normal levels.