AimTo investigate the intermittent hypoxia and high-fat diet promoting the formation of atherosclerosis through increasing expression of lipoprotein-associated phospholipase A₂ (Lp-PLA₂) and oxidized low density lipoprotein (ox-LDL).MethodsUsing randomized controlled study, prospective animal and factorial experiment, the animal models were established by intermittent hypoxia and high-fat diet.24 New-Zealand white rabbits (4 months old) were divided into the following 4 groups: control group, intermittent hypoxia group(IH), high-fat-feeding group(HFD) and intermittent hypoxia & high-fat-feeding group (IH+HFD).Each group had 6 rabbits.Rabbits in IH group and IH+HFD group were placed in a cabin which nitrogen and air were periodically infused every 5 minutes for 8 h/day.The lowest level of oxygen concentration was at 8%.The highest level of oxygen concentration was at 21%.The HFD group and IH+HFD group were fed with fat-rich-stoyer.The intervention experiment lasted for 12 weeks.Blood samples for measurements of Lp-PLA₂ and ox-LDL were collected at 0 w, 4 w, 8 w and 12 w.The formation of atherosclerosis in the aortic arch and abdominal aorta was observed.ResultThe Lp-PLA₂ level of IH group, HFD group and IH+HFD group at 8th and 12th week was higher than control group and at 4th week, the difference has statistic significance (p<0.05).The Lp-PLA₂ level of IH+HFD group at 4th, 8th and 12th week was higher than control group, IH group and HFD group(p<0.05).The two factors of IH and HFD had significant synergistic effects on the Lp-PLA₂ at 4th, 8th and 12th week（p=0.000,p=0.001,p=0.000）.The ox-LDL level of IH group, HFD group and IH+HFD group at 4th, 8th and 12th week was higher than control group(p<0.05).It was higher at 4th week than at 8th and 12th week (p<0.05).The ox-LDL level of IH+HFD group at 4th, 8th and 12th week was higher than control group, IH group and HFD group(p<0.05).The two factors of IH and HFD had significant synergistic effects on the ox-LDL at 4th week（p=0.000）, however they had no significant synergistic effects at 8th and 12th week（p=0.104 and p=0.166）.The formation of atherosclerosis was observed by oil red "O" staining in abdominal aortic and by HE staining in aortic arch and abdominal aorta under IH and HFD intervention.ConclusionThe intermittent hypoxia and high-fat diet can promote the formation of atherosclerosis through increasing expression of Lp-PLA₂ and ox-LDL.