[Effect of N-acetyl-seryl-aspartyl-lysyl-proline on regulation of expression of ras-raf-ERK1/2 signal transduction pathway in lung of rats with silicosis].

OBJECTIVE: to investigate the effect of N-acetyl-seryl-aspartyl-lysyl-proline (AcSDKP) on the expressions of c-Raf, ERK1/2 and TGF-ß1 in the lung of rats with silicosis, thus to investigate the regulating of AcSDKP on the Ras-Raf-ERK1/2 signal transduction pathway. METHODS: rats were instilled with silica through trachea as silicotic models and administered AcSDKP in the experiment. Rats were divided into 6 groups randomly, 10 rats in each group: Control 1 and 2 of silicotic model: each rat was intratracheally instilled with 1.0 ml normal sodium and was killed after 4 or 8 weeks; Silicotic model 1 and Silicotic model 2: each rat was intratracheally instilled with 1ml silica suspension and was killed after 4 or 8 weeks; Anti-fibrosis treatment of AcSDKP: after each rat was intratracheally instilled with 1ml silica suspension for 4 weeks, AcSDKP 800 microg × kg(-1) × d(-1) was administered into every rat and rats were killed at the eighth week; Preventing fibrosis treatment of AcSDKP: after AcSDKP 800 microg × kg(-1) × d(-1) was administered into every rat for 48 hours, each rat was intratracheally instilled with 1.0 ml silica suspension and rats were killed at the eighth week. The expression of c-Raf, phospho-c-Raf, ERK1/2, phospho-ERK1/2 and TGF-ß1 was measured by immunohistochemistry and western blot assay. RESULTS: compared with the corresponding control groups, the expressions of phospho-c-Raf, phospho-ERK1/2 and TGF-ß1 increased in the lung tissue of the silicotic models. Compared with the corresponding model groups, after administration AcSDKP, the expressions of phospho-c-Raf, phospho-ERK1/2 and TGF-ß1 in the lung tissue reduced obviously. In anti-fibrosis treatment of AcSDKP group, expressions of phospho-c-Raf, phospho-ERK1/2 and TGF-ß1 decreased to 52.25%, 51.72% and 67.74% compared with those of the silicotic model 1, and expressions of phospho-c-Raf, phospho-ERK1/2 and TGF-ß1 decreased to 49.37%, 55.76%, 65.63% compared with those of the silicotic model 2; In preventing fibrosis treatment of AcSDKP group, expressions of phospho-c-Raf, phospho-ERK1/2 and TGF-ß1 decreased to 54.64%, 55.76% and 78.91% compared with those of the silicotic model 2 (P < 0.05) while the expressions of c-Raf and ERK1/2 were not different significantly among each groups. CONCLUSION: AcSDKP possibly plays an important role in anti-silicotic fibrosis by blocking the TGF-ß-induced Ras-Raf-ERK1/2 signal transduction pathway.

Therapeutic effects of conditioned medium from bone marrow-derived mesenchymal stem cells on epithelial-mesenchymal transition in A549 cells.

Pulmonary fibrosis (PF) is a chronic lung disease. The transforming growth factor-ß1 (TGF-ß1)/Smad3 signaling pathway plays an important role in the pathogenesis of pulmonary fibrosis. Bone marrow-derived mesenchymal stem cells (BMSCs) have been shown to be a modulator of the molecular aspects of the fibrosis pathway. However, it is still unknown as to whether the conditioned medium from BMSCs (BMSCs-CM) inhibits the epithelial-mesenchymal transition (EMT) process. This study confirmed the hypothesis that BMSCs-CM exerts an anti-fibrotic effect on human type II alveolar epithelial cells (A549) by suppressing the phosphorylation of Smad3. We used the A549 cells in vitro to detect morphological evidence of EMT by phase-contrast microscopy. These cells were randomly divided into 4 groups as follows: the control group, the TGF-ß1 group, the SIS3 (specific inhibitor of Smad3) group and the BMSCs-CM group. The immunofluorescence method was used to determined the location of E-cadherin (E-calcium mucins; E-cad), α-smooth muscle actin (α-SMA) and p-Smad3. The expression levels of E-cad, CK8, α-SMA, vimentin, p-Smad3, Snail1, collagen I (COLI) and collagen III (COLIII) were detected by western blot analysis. Following exposure to TGF-ß1, the A549 cells displayed a spindle-shaped fibroblast-like morphology. In accordance with these morphological changes, the expression levels of E-cad and CK8 were downregulated, while the expression levels of α-SMA and vimentin were upregulated. Along with this process, the expression levels of p-Smad3, Snail1, COLI and COLIII were increased. However, the cells in the BMSCs-CM group and SIS3 group exhibited a decrease in the levels of α-SMA and vimentin (which had been upregulated by TGF-ß1), and an increase in the levels of E-cad and CK8 expression (which had been downregulated by TGF-ß1). On the whole, these results indicated that BMSCs-CM suppressed the EMT which might be associated with TGF-ß1/Smad3. This study provides the theoretical basis for the research of the mechanisms responsible for pulmonary disease.

Electro-optical response of the in-plane switching liquid crystal device fabricated using two-easy-axes substrate.

We investigate the electro-optical response of an in-plane switching (IPS) liquid crystal (LC) device, which is fabricated using the two-easy-axes substrate. The two-easy-axes substrate is fabricated by slightly rubbing the substrate in two different directions. Experimental results indicate that the IPS LC device fabricated using the two-easy-axes substrate has a lower threshold voltage and a faster response time than the traditional IPS LC device, which is fabricated using the unidirectionally rubbed substrate. The weak anchoring condition and the anchoring strengths in two different rubbing directions on the substrate contribute to the fast electro-optical response of the IPS LC device.