Screening key factors from bone marrow mesenchymal stem cells for alleviating silicosis in mice / 中国职业医学

ABSTRACT

OBJECTIVE: To explore the mechanism of bone marrow mesenchymal stem cells(BMSCs) in alleviating silica-induced lung injury in mice. METHODS: Ten specific pathogen free healthy male C57 BL/6 mice were selected for isolating BMSCs and bone marrow macrophages(BMDMs). Transwell chamber was used, BMDMs were inoculated onto the upper chamber and BMSCs in the lower chamber. We divided them into sequencing control group and silica(SiO_2) exposure group. All cells were pre-stimulated with 50 μg/L mass concentration lipopolysaccharide for 4 hours. In the SiO_(2 ) group, 250 mg/L mass concentration SiO_2 was added to the upper chamber of transwell and cultured for 16 hours. Total RNA was extracted from the BMSCs collected from the lower chamber. HiSeq/MiSeq high-throughput sequencing technology was used to detect the BMSCs RNA paired-end sequencing. Transcriptome sequencing data was obtained and bioinformatics analysis was performed. Another 12 specific pathogen free healthy male C57 BL/6 mice were randomly divided into control group and experimental group. All mice received one intra-tracheal injection of 20.0 μL(250 g/L mass concentration) of silica dust suspension. After 6 hours, the mice in the control group was given 500.0 μL of 0.9% sodium chloride solution and mice in the experimental group was given 500.0 μL of BMSCs suspension(cell density 1×10~9/L) by tail vein infusion.Mice were sacrificed 12 hours later. The relative mRNA expression of interleukin(IL)-1 Ra, IL-10, tumor necrosis factor stimulating gene 6(TSG-6) and prostaglandin E2(PGE2) in lung tissues of mice were measured by quantitative real-time PCR(q-PCR). Meanwhile, BMDMs and BMSCs transwell co-culture models were established. The cells were divided into 5 groups BMSCs group, BMSCs+BMDMs group, BMSCs+BMDMs+ lipopolysaccharide(LPS) group, 50 mg/L SiO_2 group, and 100 mg/L SiO_2 group. After 16 hours of corresponding SiO_2 stimulation, BMSCs of each group were collected and the relative mRNA expression levels of IL-1 Ra, IL-10, TSG-6, and PGE2 in the cells were detected by q-PCR. RESULTS: Compared with sequencing control group, BMSCs co-cultured with SiO_2 had 19 genes up-regulated and 21 genes down-regulated, including 10 genes up-regulated for more than 2.0-fold. The relative mRNA expression of IL-1 Ra, IL-10, PGE2 and TSG-6 in the lung tissue of mice increased in the experimental group than that of the control group(all P<0.05). The relative mRNA expression of TSG-6 increased by 37.5 times higher than that of the control group. Compared with the BMSCs+BMDM+LPS group, the level of TSG-6 mRNA relative expression increased in both the 50 mg/L SiO_2 group and the 100 mg/L SiO_2 group(all P<0.05). CONCLUSION: TSG-6 could be the key factor of BMSCs that can attenuate silica-induced lung injury.