Aim To observe the effect of minocycline on atherosclerosis(As) after the treatment of atherosclerosis plaque-intervention with changes in the level of molecular pathology,evaluate drug effects on treatment of As and analyze its mechanism. Methods 5 as normal control group were randomly taken from 40 New Zealand rabbits. 35 rabbits were used as atherosclerotic animal model after balloon-induced arterial injury to the epithelium and use of high-fat diet for 3 months.In addition to death or illness of five rabbits during experiment,remaining 30 rabbits were randomly divided into 4 groups,namely,model group(8 rabbits,high fat diet for 1 month),reconverted normal diet group(7 rabbits,conventional feeding for 1 month),fluvastatin treatment group(7 rabbits,given fluvastatin 1 mg/(kg·d) intervention for 1 month);minocycline treatment group(8 rabbits,given minocycline with a dose on 3 mg/(kg·d)).The animals were sacrificed and the abdominal aorta in each group were cut,paraffin-embedded sections,Masson staining were used to observe the morphological changes of As plaque and inflammatory cells,expression levels of matrix metalloproteinases(MMP) were examined with the immuno-histochemistrical staining,using in situ hybridization-Tunel staining detection of apoptotic cells in As plaque of these animal. Results Histopathology artery wall by Masson staining showed no pathological changes in normal group,model control group and reconverted normal diet group showed the typical features of As lesions,and two groups with treatment of the minocycline and fluvastatin significantly reduce the pathological change,especially the former.In plaque of As of each group,macrophage(RAM-11) and expression levels of matrix metalloproteinase(MMP-3 and MMP-9)had positive correlation (P<0.001).But macrophage content in plaque and MMP expression level in the minocycline treatment and the fluvastatin treatment group were significantly lower compared with the model control group(P<0.05).And smooth muscle cells markedly increased in minocycline group. Conclusion Minocycline can relieve severity of As treatment of diseases and improve the stability of atherosclerotic plaque.