The Study On Coagulation Disorders And Atorvastatin Intervention Caused By IH Of OSA Model In Rats

Obstructive sleep apnea hypopnea syndrom (OSAHS) is a highly prevalent disease, characterized by repeated hypoxia/reoxygenation, namely the intermittent hypoxia (IH), recognized as an independent risk factor for various cardiovascular diseases. Clinical research showed obstructive sleep apnea (OSA) could cause hypercoagulation, while the mechanism remains unclear and related basic research rare. Basic research is ongoing to explore medical intervention on prevention of cardiovascular complications induced by OSA. Statins have remarkable efficacy in cardiovascular field, while can the patients with OSA benefit from the statins? So IH of OSA model in rats was developed to observe if IH can induce hypercoagulation and explore the mechanisms, and with atorvastatin intervention to evaluate its protection effect of the injury initiated by IH. The research was expected to provide experimental data and theoretical basis for clinical work.Contents1. Observe if IH of typical OSA model can induce hypercoagulation and explore the mechanisms2. To evaluate if atorvastatin intervention can inhibit or reverse the damage induced by IH with application of atorvastatin in different time and analyze the impact on the efficacy of treatment timeMethods1. Twelve adult male Wistar rats, were randomly divided into2groups, the IH group and the control group, each group of six. IH group exposed to IH environment, the frequency of45times/h,5-8%, the lowest oxygen concentration,8hours a day; the control group normal oxygen. The rats were sacrificed12weeks later. Blood were collected to prepare serum, platelet-rich plasma and platelet-poor plasma respectively. The positive rates of platelet-rich plasma platelet membrane antibody CD62p and CD63were tested for by flow cytometry, platelet-poor plasma levels of FIB, Ⅷ were detected by coagulation assay to evaluate the coagulation status. The thoracic aorta were taken to observe the thrombosis and the injury of vascular endothelium by light microscope and electron microscope. And detect serum levels of inflammatory factors of TNF-a, IL-8, IL-1β by radioimmunoassay; serum levels of MDA and SOD with colorimetric method; plasma levels of NO and vWF by nitrate reductase assay and immunonephelometry respectively; to explore the mechanism of coagulation disorders caused by IH.2. Twenty-four adult male Wistar rats were randomly divided into4groups:statin beginning group (atorvastatin given gavage10mg/kg/d at the beginning of IH expose), statin4w group (atorvastatin given gavage10mg/kg/d after exposure of IH for4weeks), free after IH group (backyard after IH exposure for8weeks)and IH group (the same as the first part), with the same IH exposure conditions in the four groups. The rats were sacrificed12weeks later. Measurements were the same as the first part. Observe and analyze the differences of the above markers among the groups.ResultsThe first part:1. Compared with control group, in IH group the platelet membrane antibody positive rates of CD62p and CD63increased significantly (p<0.01); levels of plasma FIB and FⅦ did not show statistical difference, but with a rising trend. The vascular pathology of light microscope and electron microscope in IH group showed thrombosis and injury of vascular endothelium.2. Levels of serum TNF-a and IL-8increased significantly in IH group than control group (p<0.01), IL-1β mildly elevated (p<0.05); serum MDA elevated (p<0.01) and SOD decreased (p<0.01); plasma level of NO decreased (p<0.01) and vWF increased (p<0.01)significantly.3. Plasma CD62p and NO showed negative correlation((r=-0.874,p<0.01). The correlations between CD62p and vWF, CD62p and MDA, CD62p and TNF-a showed significant positive correlation (r=0.658,0.681,0.636,p<0.05).The second part:1. In statin beginning group plasma levels of CD62p and CD63were significantly reduced(F=19.228,9.608, P=0.000) than IH group. Levels of FIB and Ⅷ showed a decreasing trend, but no statistical difference among groups. Pathology revealed that in statin beginning group vascular endothelial injury was significantly reduced with no obvious thrombosis.2. In statin beginning group, serum levels of TNF-α、IL-8、IL-1β and MDA significantly decreased, SOD elevated (F=6.182,5.627,3.904,7.048,4.906, P <0.05), plasma level of NO increased and vWF decreased(F=7.709,5.700, P<0.01) than IH group.3. In statin beginning group, plasma levels of CD62p and CD63, serum levels of inflammation and oxidative stress markers were decreased further than statin4w group and free after IH group (P<0.05), and light microscopy and electron microscopy showed vascular endothelial injury significantly improved.Conclusions1. IH of OSA model caused platelet activation and hypercoagulation state with thrombosis.2. IH of OSA caused oxidative stress, systemic inflammation and vascular endothelial injury. And oxidative stress and systemic inflammatory involved in vascular endothelial injury.3. Platelet activation was not only related to vascular endothelial injury, oxidative stress and inflammation might directly involve in platelet activation process, leading to hypercoagulable state.4. Atorvastatin inhibited platelet activation and hypercoagulation state, and it could improve endothelial injury.5. The protective effect of atorvastatin may be achieved through inhibiting the activity of inflammatory cytokines and oxidative stress.6. The protection effect of earlier application of atorvastatin was more significant.