RESUMO
OBJECTIVE: To discuss the effect of N-acetylcysteine (NAC) upon matrix metalloproteinases (MMP) in the atherosclerotic processes in rabbit carotid. METHODS: The atherosclerotic models were generated in vitro by injuring rabbit internal carotid with arterial canal balloon. These rabbits were divided into 3 groups (15 mg/kg NAC, 30 mg/kg NAC and control group) and treated for 8 weeks. HE staining and immunohistochemistry were used to observe the plaque formation and the distribution of MMPs and ox-LDL. ELISA was used to detect the level of ox-LDL. And the protein levels of MMP-2 and MMP-9 in rabbit venous blood were detected by SDS PAGE zymography. The mRNA level of MMP-2 and MMP-9 were measured by RT-PCR and electrophoresis. RESULTS: As compared with the control group, NAC (15 mg/kg) group had a reduction of neointima of arterial lumen [(1.79 +/- 0.24) vs (2.78 +/- 0.17) mm2]. A decrease of endothelial thickness [(0.16 +/- 0.01) vs (0.24 +/- 0.02) mm2] and an increase of vascular cavity transverse [(0.58 +/- 0.10) vs (0.33 +/- 0.1) mm2] (P < 0.05) were observed. At week 8, the oxLDL levels decreased by 16% in NAC (30 mg/kg) group [(30.5 +/- 1.2) vs (36.2 +/- 1.8) mmol/L] (P < 0.01). Serum levels of pro-MMP-2, MMP-2 and pro-MMP-9 decreased markedly [INT/mm2: (311 +/- 19, 208 +/- 8, 283 +/- 7 vs 619 +/- 17, 574 +/- 8, 564 +/- 10) respectively, P < 0.01] in NAC (30 mg/kg) group. The levels of mRNA expression of MMP-2 and MMP-9 were (2.4 +/- 0.4, 2.8 +/- 0.2) vs (3.4 +/- 0.3, 3.7 +/- 0.5) respectively (P < 0.05). CONCLUSION: NAC inhibits the atherosclerotic formation, suppresses the levels of ox-LDL, MMP-9 and MMP-2 and downgrades the expression of matrix metalloproteinase mRNA.
