[Inhibitory effect of N-acetylcysteine upon atherosclerotic processes in rabbit carotid]

To discuss the effect of N-acetylcysteine (NAC) upon matrix metalloproteinases (MMP) in the atherosclerotic processes in rabbit carotid.

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.

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).

NAC inhibits the atherosclerotic formation, suppresses the levels of ox-LDL, MMP-9 and MMP-2 and downgrades the expression of matrix metalloproteinase mRNA.