[Endarterium injury and the related pathway in chronic intermittent hypoxia rats]

To examine the pathological change and intima thickness of thoracic aorta, detect the serum concentration of hypoxia-inducible factor-1α (HIF-1α), oxidized LDL (ox-LDL), and pentraxin 3 (PTX3) in the rat model of chronic intermittent hypoxia (CIH), and to determine the effect of CIH on endarterium injury and its possible pathway.

Twenty-four male Sprague-Dawley (SD) rats were divided into 4 groups: a CIH+Nacetylcysteine (NAC) group, a CIH+normal saline (NS) group, a CIH control group and a control group. CIH rats were subjected to alternating cycles of hypoxia (6%-8% O2 in N2 for 20-25 s) and normoxia (21% O2 in N2 for 2 min) every 180 s for 7 h/d. Rats in the control group were not treated. Rats in the CIH+NAC group were treated with NAC [800 mL/(kg.d)] intraperitoneal injection, and rats in the CIH+NS group were treated with NS [5 mL/(kg.d)] intraperitoneal injection. After 42 day treatment, the rats were sacrificed, blood taken, and thoracic aorta cut off. The serum concentration of HIF-1α, ox-LDL, and PTX3 were detected by ELISA. The thickness of intima was taken by computer digital image analysis.

Vascular endothelial cell injury and detachment were found in the thoracic aorta in the CIH and the CIH+NS group. The intima in the CIH and the CIH+NS group was thicker than that in the control and the CIH+NAC group (P<0.001). The serum concentration of HIF-1α, ox-LDL, and PTX3 in the CIH and the CIH+NS group was higher than that in the control and the CIH+NAC group (P<0.001). The serum concentration of HIF-1α, ox-LDL, and PTX3 was pairwise positive correlation, and the serum concentration of ox-LDL and PTX3 was positively correlated with the thickness of intina (P<0.001).

The vascular endothelial cell injury and endarterium thickening can be induced by CIH. It is an important pathway that CIH activates oxidative stress and elevates the levels of HIF- 1α, ox-LDL, and PTX3.