[Effect of human silicotic alveolar macrophages on expression of matrix metalloproteinase, tissue inhibitor of metalloproteinase and collagen in human lung fibroblasts].

OBJECTIVE: To study the effect of culture supernatant of alveolar macrophage alveolar macrophages (AM) stimulated by SiO2 on the expression of matrix metalloproteinases (MMP-1), tissue inhibitor of metalloproteinase-1 (TIMP-1) and collagen of fibroblast human embryonic lung fibroblasts (HELF) in the development of silicosis fibrosis. METHODS: AMs were collected from a silicotic patient by bronchoalveolar lavage and exposed to SiO2, cultured human embryo lung fibroblast were allocated into a treated group, a control group, a positive group, and a blank group. HELF was incubated with the cultured supernatant of AMs for 6, 12, 18, 24, 36, 48 h. Immunocytochemical and Western blot technology were used to detect MMP-1 and TIMP-1 expressions in HELF and collagen expression in supernatant of HELF respectively. RESULTS: The supernatant of AM exposed to SiO2 significantly decreased the expressions of MMP-1 (0.0605 +/- 0.0201, 0.0519 +/- 0.0117, 0.0412 +/- 0.0105 and 0.0213 +/- 0.0106 in the treated group at 18, 24, 36 and 48 h) compared with the control group and the blank group (P < 0.05, P < 0.01) but stimulated expressions of TIMP-1 and collagen (P < 0.05, P < 0.01). The ratio of TIMP-1 to MMP-1 increased. The ratio of TIMP-1 to MMP-1 was positively correlated with the expression of collagen III (r = 0.88, P < 0.01). CONCLUSION: Through AM mediation SiO2 can accelerate the expression of TIMP-1 and collagen, and inhibit the expression of MMP-1. The imbalance between the expression of TIMP-1 and that of MMP-1 is related with the abnormal increase in collagen III.

[Effect of silicosis alveolar macrophages on expression of c-myc in human embryo lung fibroblast in vitro].

OBJECTIVE: To study the effect of silicosis alveolar macrophages (AM) restimulated by SiO(2) on expression of c-myc oncogene in human embryo lung fibroblasts. METHODS: The bronchoalveolar lavage of silicosis patients was collected. AMs were divided into 2 groups: (1) SiO(2): AMs were stimulated with SiO(2) (30 microg/ml) for 1, 2, 6, 12, 24 and 36 h; (2) control: treated for the same time without SiO(2). Fibroblasts were cultured with different AMs supernatants for 2 h or 7 h respectively. The expression of c-myc mRNA was determined by RT-PCR and protein by Western Blot. RESULTS: There was no c-myc expression when fibroblasts were static. The supernatants in the S6 group stimulated expression of c-myc mRNA and protein, with the peak expression at 2 h and 7 h respectively. In the control group, AMs supernatants cultured in different time stimulated expression of c-myc mRNA and protein with the most evident expression at 12 h. The ratios were 0.749 +/- 0.088 and 0.759 +/- 0.101 respectively. Compared with control in the same period, c-myc mRNA and protein expression were significantly stronger treated with the supernatants in which AMs were stimulated for 1 h, 2 h and 6 h by SiO(2) (P < 0.05 or P < 0.01). CONCLUSION: AMs stimulated with SiO(2) has the ability to induce c-myc oncogene expression in human embryo lung fibroblasts.

[Effect of SiO2 on the expression of MMP-9 and TIMP-1 in human alveolar macrophages in vitro].

OBJECTIVE: To study the effect of SiO(2) on the expression of matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinase (TIMP) in human alveolar macrophages (AMs) associated with the pathogenesis of silicotic fibrosis. METHODS: AMs were collected from a silicotic patient by bronchoalveolar lavage, and exposed to SiO(2) (50 microg/ml), and cultured in DMEM without serum for different time (2, 6, 12, 18, 24, 36 h). Immunocytochemical method was used to detect the level of expression of MMP-9 and TIMP-1 in AMs. RESULTS: The expression of MMP-9 in AMs exposed to silica was up-regulated, and reached the peak at 18 h [average optical density: (0.440 +/- 0.021) vs (0.390 +/- 0.011), P < 0.05]. After that, the expression reduced markedly. However, the expression of TIMP-1 of AMs were not significantly different from the control group [average optical density: (0.175 +/- 0.019) vs (0.162 +/- 0.044), P > 0.05]. CONCLUSION: SiO(2) could induce up-expression of MMP-9 in AMs. Degradation of basement membrane by MMP-9 produced by AMs at early stage of lung injury may associate with the immigration of various cells including lung fibroblasts into the injured region.

[The effect of nitric oxide on acute lung injury following ischemia/reperfusion of hind limbs in the rat].

On a model of reperfusion after ischemia in the hind limbs (LIR) of rats, we used aminoguanidine (AG) which inhibits nitric oxide synthase (NOS) and L-arginine (L-Arg), one of the substrates in the process of nitric oxide synthesis, to observe the changes in NO, NOS, malondialdehyde (MDA), myeloperoxidase (MPO) and wet/dry ratio (W/D) in both skeletal muscles and the lung as well as the changes in phosphatidyl choline (PC) of lung surfactant. The morphologic changes were observed with microscopy. It was observed that the values of NOS, MPO, MDA of the muscle and lung in LIR group increased significantly and the content of PC decreased obviously compared with those of the normal control. Pulmonary observation revealed that after LIR leucocyte assembling and infiltration took place, which was dominated by polymorphocytes with broadened pulmonary interstitial tissue. In LIR+L-Arg group the above changes were reversed, and in LIR+AG group the injuries became more serious. The results obtained suggest that the activity of NOS and the production of NO following ischemia/reperfusion of hind limbs increased significantly, and that the endogenous NO may play a protective role during the early stage of acute lung injury after LIR.

[Effect of human silicotic alveolar macrophages on the expression of matrix metalloproteinase-1 and tissue inhibitor of metalloproteinases-1 in human lung fibroblasts].

OBJECTIVE: To study the effect of the cultured supernatant of human silicotic alveolar macrophages (AM) on the expression of matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of metalloproteinase-1 (TIMP-1) in human lung fibroblasts (FB). METHODS: Human alveolar macrophages were collected from a silicotic patients by bronchoalveolar lavage and exposed to SiO(2), then the cultured supernatant were incubated with human fetal lung fibroblasts for 6, 12, 18, 24, 36, 48 h. The immunocytochemical method was used to detect the level of expression of MMP-1 and TIMP-1 in lung fibroblasts. RESULTS: The expression of MMP-1 in FB in 24 h incubation was lower in cultured supernatant of silicotic AM unexposed to SiO(2) than in blank control [integrated OD (IOD)]: 0.103 +/- 0.014 vs 0.133 +/- 0.023), while the expression of TIMP-1 was higher (IOD: 0.108 +/- 0.012 vs 0.065 +/- 0.006). The expression of MMP-1 in FB in cultured supernatant of AM exposed to SiO(2) for 24 h was further decreased (IOD: 0.062 +/- 0.008 vs 0.133 +/- 0.023), while that of TIMP-1 was further increased (IOD: 0.143 +/- 0.015 vs 0.065 +/- 0.006). CONCLUSION: SiO(2) may affect the expression of MMP-1 and TIMP-1 system through AM mediation and participate in the formation of lung fibrosis.

[The protective effect of taurine on lung injury following limbs ischemia/reperfusion of rats].

AIM: On the model of limb ischemia/reperfusion (LIR), the effects of taurine on pulmonary morphological changes in rats were observed. METHODS: Wistar rats were divided into three groups (n=8): control group, ischemia/reperfusion group (IR) and taurine + IR (Tau + IR). Then macroscopic inspection and optical and transmission electron microscopies (TEM) were performed to assess the morphological changes of the lung tissues and their lung index (LI) and lung permeability index (LPI) and reactive oxygen species (ROS), malondialdehyde (MDA) were measured as well. RESULTS: The morphological changes of lung tissue after LIR were characterized by an increase of permeability of the alveoli-capillary membrane and infiltration of inflammatory cells. Under optical microscopy, there were congestion and swelling in pulmonary microvessels with broadened the spaces around the blood vessels. Under TEM, a number of tight-junctional regions between adjacent alveolar epithelial cells and between pulmonary microvessels endothelium were "open". The LI, LPI, MDA and ROS increased. The specimens of Taurine + IR group revealed slight to moderate degrees of damages in the lung tissues. CONCLUSION: Taurine protects lung from LIR in rats and the protective action on tight-junctional regions between cells and anti-oxygen is one of the protective mechanisms of taurine.