OBJECTIVETo explore the elastic lamina degradation and the collagen remodeling of aortic artery as well as oxides stress and inflammation of the apolipoprotein (Apo E) deficient mice with or without experimental hypertension.

METHODSEighty male Apo E deficient mice were fed with high-fat diet beginning at six weeks of age. At 8-week old, they were randomly divided into hypertension group and control group (n=40 each), the mice in hypertension group were subjected the suprarenal aortic constriction operation and then randomly divided into two subgroups: 15 weeks age and 30 weeks age groups. At the end of experiment, the vascular elastic lamina degradation and the content of collagen were determined by morphological method, plasma ICAM-1 level was measured by ELISA, and the rennin activity measured by radioimmunoassay, the superoxide anion detected by fluorescence, the MOMA-2 observed by immunofluorescence in all animals. mRNA expression of NF-κB P65 and MMP9 was detected by real-time PCR.

RESULTIn 15-week old group, the elastic lamina degradation Grade II and the intima-media thickness in the hypertension group were significantly higher than in the control group [(5.4±3.3)% vs. (8.9±2.5)%, P<0.05; (98.66±18.90) µm vs. (70.08±11.71) µm, P<0.05]. In 30-week old group, the elastic lamina degradation Grade III, the III type of collagen and the intima-media thickness were also significantly higher than in the control group [(15.2±3.7)% vs. (8.1±3.3)%, P<0.01; (23.00±7.73)% vs. (11.00±3.82)%, P<0.05; (147.31±22.60) µm vs. (103.98±17.21) µm, P<0.01]. The level of ICAM-1 in hypertension group was significantly higher than that of control group in both 15-week old and in 30-week old mice [(46.3±3.7) µg/ml vs. (40.6±5.7) µg/ml, P<0.05; (56.0±3.1) µg/ml vs. (45.2±2.8) µg/ml, P<0.05]. The superoxide anion, the MOMA-2, mRNA expression of NF-κB P65 and MMP9 in the hypertension group were significantly higher than in the control group in both 15-week old and in the 30-week old mice. The increase in hypertension group was more pronounced in the 30-week old mice than in the 15-week old mice.

CONCLUSIONThe elastic lamina degradation and the collagen remodeling of aortic artery as well as oxides stress and inflammation are more significant in the Apo E deficient mice with hypertension than in control Apo E deficient mice.