The effects of aerobic exercise on atherosclerotic plaques in apolipoprotein E gene deficient mice / 中华物理医学与康复杂志

ABSTRACT

Objective To investigate the influence of aerobic exercise on the vulnerability of atherosclerotic plaques and to observe the concentration of matrix metalloproteinase-9 ( MMP-9 ) and matrix metalloproteinase-14(MMP-14) in carotid atherosclerotic plaques in apolipoprotein E (APoE) gene deficient mice.Methods Eighty male, APoE gene deficient mice were divided into two equal groups an aerobic exercise group and a limited action control group. Carotid atherosclerotic lesions were induced by perivascular constrictive collars placed on the right common carotid artery. Blood lipid levels in the exercise group were measured after 8 weeks of treadmill running and also in the control group. The morphological characteristics of carotid atherosclerotic plaques were observed in the two groups. Plaque area and fibrous cap thickness were measured. Lipid and collagen positive areas were quantified and the ratios correlated with the entimal areas were calculated. Plaque rupture rate and vulnerable index were calculated.Immunostaining was used to detect MMP-9 and MMP-14 expression in the atherosclerotic plaques. The mRNA levels of MMP-9 and MMP-14 mRNA in the fresh carotid plaques were quantified using a real-time reverse-transcriptase polymerase chain reaction (RT-PCR). Western blotting was performed for examining MMP-9 and MMP-14 protein expression in the fresh carotid plaques.Results No significant difference in serum lipid profiles or plaque area was found between the exercise and control groups. Compared with the control group, mean fibrous cap thickness, cap/core ratio and collagen content were all significantly higher in the exercise group, and lipid content was significantly lower. Plaque rupture rate and the vulnerable index were both significantly lower in the exercise group. Immunostaining showed that MMP-9 and MMP-14 expression were lower in the exercise group compared with the control group.The mRNA expression of MMP-9 and MMP-14 was also significantly lower.Conclusions Aerobic exercise can decrease the expression of MMP-9 and MMP-14 in carotid atherosclerotic plaques in ApoE gene deficient mice. Aerobic exercise may play a role in forestalling atherosclerosis by increasing the stability of plaque and decreasing plaque vulnerability.