[Expression changes of miRNA-29b-3p and miRNA-34c-3p in lung tissue of rats exposed to silica and A549 cells].

Objective: To investigate the role of microRNA-29b-3p (miRNA-29b-3p) and miRNA-34c-3p in the process of pulmonary fibrosis, we detected the expression levels of miRNA-29b-3p and miRNA-34c-3p in the lung tissue of rats exposed to silica and A549 cells. Methods: SPF male Wistar rats were randomly divided into 1, 7, 14, 21, 28 d control group and silica (SiO(2)) dusting group, with 6 rats in each group. One-time non-exposure method was used to infuse 1ml SiO(2) suspension. The rat SiO(2) dusting group was established in the liquid, and the control rats were intratracheally injected with 1 ml of sterile physiological saline in the same manner. The lung tissues of each group were collected at the corresponding time points after dusting. Three of the rats were taken out for pathological observation, and the other three were used to screen differentially expressed miRNAs in lung tissue by miRNA microarray technology. A549 cells were cultured at the in vitro cell level and divided into control group, SiO(2) stimulation group and TGF-ß(1) stimulation group, and cells were collected at 12, 24 and 48 h after treatment. The expression levels of miRNA-29b-3p and miRNA-34c-3p in rat lung tissue and A549 cells were verified by real-time PCR (qRT-PCR), target gene prediction of miRNA-29b-3p and miRNA-34c-3p and perform GO enrichment analysis and KEGG pathway analysis. Results: The weight growth rate of the control group was significantly higher than that of the SiO(2) dusting group. Compared with the control group, the lung mass and lung coefficient of the SiO(2) dusting group were significantly increased (P<0.05). The inflammatory response of the lungs in the control group was significantly reduced at 21 and 28 days, and the inflammatory cells infiltrated in the lung tissue of the SiO2 group. The rats in the control group had a small amount of collagen at 21 and 28 days. A large amount of collagen fiber deposition began to appear in the lung tissue of rats exposed to SiO(2) for 21 days. Compared with the control group, the expression levels of miRNA-29b-3p and miRNA-34c-3p in the SiO(2) dusting group were significantly down-regulated, and there was significant difference compared with the control group (P<0.05). The expression levels of miRNA-29b-3p and miRNA-34c-3p in A549 cells treated with SiO(2) and human recombinant TGF-ß1 were significantly lower than those in the control group at 24 h and 48 h, and the difference was statistically significant (P<0.05). Conclusion: Down-regulation of miRNA-29b-3p and miR-34c-3p in rat lung tissue A549 cells may be associated with the development of early silicosis and is expected to be an indicator of early silicosis diagnosis and prognosis.

[Preliminary analysis of differential expression of miRNA-423-5p and miRNA-26a-5p in lung tissue of early silicotic rats].

Objective: To screen the changes of microRNA (miRNA) expression profiles in lung tissues of early silicosis rats, and provide a basis for functional analysis of differential microRNA. Methods: SPF Wistar male rats were randomly divided into a negative control group and SiO(2)-exposed groups, with 30 rats in each group. The model of silicosis in rats was established by intratracheal instillation of 1 ml SiO(2) suspension, and the control rats were treated with 1mL in the same way to sterilize normal saline. The lung tissues of two group were collected at the 1, 7, 14, 21, 28 d after SiO(2)-exposed. Three of the rat lung tissues were used for pathological observation, and the other three were used to screen differentially expressed miRNAs in lung tissue by miRNA microarray technology. miRNA chip screening and RT-qPCR were used to verify the expression levels of miRNA-423-5p and miRNA-26a-5p in the two groups. miRNA-423-5p and miRNA-26a-5p are predicted by target genes and analyzed by GO (gene ontology) enrichment analysis and KEGG (kyoto encyclopedia of genes and genomes) pathway analysis. Results: In the control group, the inflammatory response of lung tissue 21 and 28 days was significantly reduced compared with 1, 7 and 14 days, and the inflammatory cells infiltrated in the lung tissue of the SiO(2)-exposed rats. The rats in the control group had a small amount of collagen at 21 and 28 days, but a large amount of collagen fiber deposition began to appear in the lung tissue of rats exposed to SiO(2) after 21 days. Compared with the control group, the expression levels of micro RNA-423-5p was significantly up-regulated and the expression of microRNA-26a-5p was significantly down-regulated in the SiO(2)-exposed rats lung tissues dust at different time points (P<0.05) . Conclusion: The up-regulation of miRNA-423-5p and the down-regulation of miRNA-26a-5p in lung tissues of early silicotic rats may be related to the occurrence and development of early silicosis.

[Repair effect of adipose-derived mesenchymal stem cells on lung injury in rats exposed to silica].

Objective: To observe the repairing effect of adipose mesenchymal stem cells (ADSCs) on lung injury induced by silica in rats. Methods: Primary ADSCs-GFP was obtained from rats. ADSCs-GFP was injected into tail vein of silicosis model rats. The expression of green fluorescence in lungs was observed regularly to determine the homing ability of ADSCs. Primary ADSCs of rats were obtained and randomly divided into control group, exposure group, vehicle group and ADSCs group. Silicosis rat model was established by non-exposed tracheal drip method. 24 hours after silica exposure, rats in ADSCs group were injected with ADSCs of 1×10(6)/kg body weight through tail vein, and the pathological changes of lung tissue were observed and evaluated 28 days after intervention. To explore the early intervention mechanism of ADSCs on pulmonary fibrosis in silicosis model rats, apoptosis-related proteins were detected by immunohistochemistry. Results: 28 days after exposure to silica, rats in the exposure group showed obvious pulmonary fibrosis. Compared with exposure group and vehicle group, ADSCs group showed less pulmonary inflammation, less silica nodules and less collagen deposition area. Immunohistochemical results showed that the expression of Caspase-3 and cytochrome C protein decreased and Bcl-2 protein increased after ADSCs transplantation. Conclusion: ADSCs infusion has an obvious intervention effect on postponing early silicosis fibrosis in rats exposed to silica, and its mechanism is related to the regulation of apoptotic process.