[Inhibition of N-acetyl-L-cysteine on expressions of matrix metalloproteinases increased by exposure to silicon dioxide in lung fibroblasts in rats].

Objective: To explore the effect of N-acetyl L-cysteine (NAC) on expressions of matrix metalloproteinases-2, 9 (MMP-2, MMP-9) in lung fibroblasts of SiO(2) exposed rats.

Methods: Seventy-five Wistar rats were divided randomly into three groups. The control group was administered with normal Saline. The model group and the interventional group were administered with SiO(2), and the interventional group was administered with NAC before SiO(2) was administered. Lung fibroblasts were isolated on day 1, 3, 7, 14, 28 after exposure to SiO(2). The expressions of MMP-2 and MMP-9 were evaluated by Immunocytochemistry and RT-PCR.

Results: (1) The expressions of protein and mRNA of MMP-2 in the model group were higher than that in the control group on all days after exposure to SiO(2) (P < 0.01). The expression of protein of MMP-9 was higher than the control group on day 1, 3, 7, and mRNA was higher on day 1, 3 (P < 0.01). (2) The expression of protein of MMP-2 in the interventional group was lower than the model group on all days, higher than the control group on day 3, 7, 14, 28, and the expression of mRNA was higher than the control group, lower than the model group, on all days (P < 0.05 or P < 0.01). The expression of protein of MMP-9 in the interventional group was lower than the model group on day 1, 3, 7, but higher than the control group on day 3, 7, and mRNA was lower than the model group on days 1, 3, higher than the control group (P < 0.05).

Conclusion: NAC inhibits the expressions of MMP-2, MMP-9 in lung fibroblasts.