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目的观察骨髓间充质干细胞(MSC)对矽尘所致大鼠肺损伤的修复作用。方法取7只无特定病原体级健康雄性SD大鼠培养MSC,并取30只同类SD大鼠随机分为对照组、染矽尘组和MSC输注组。对照组大鼠气管内注射1.0 ml生理氯化钠溶液,染矽尘组和MSC输注组均气管内注射1.0 ml质量浓度为40 g/L的矽尘混悬液,其后,MSC输注组大鼠鼠尾静脉注射0.5 ml细胞密度为5×109/L的MSC,其余2组鼠尾静脉注射0.5 ml生理氯化钠溶液。第28天处死大鼠,观察肺组织病理学改变情况,并检测肺脏器系数、肺灌洗液(BALF)细胞计数和血清丙氨酸氨基转移酶(ALT)、天冬氨酸氨基转移酶(AST)、肌酸激酶(CK)、乳酸脱氢酶(LDH)活力和尿素氮(BUN)、肌酐(Cr)水平。结果染矽尘组和MSC输注组大鼠的肺脏器系数均高于对照组[(0.528±0.044)%vs(0.435±0.027)%,(0.492±0.042)%vs(0.435±0.027)%,P<0.05],MSC输注组肺脏器系数低于染矽尘组[(0.492±0.042)%vs(0.528±0.044)%,P<0.05]。病理学检查显示:对照组无肺部炎症、矽结节和纤维化改变;染矽尘组大鼠肺部炎症最严重,并可见大量矽结节和胶原纤维沉积;与染矽尘组比较,MSC输注组肺部炎症减轻,矽结节数量减少,胶原纤维沉积面积较小。对照组大鼠BALF的总细胞数、巨噬细胞、中性粒细胞和淋巴细胞计数分别为(5.86±1.28)×106/L、(5.45±1.30)×106/L、(0.11±0.04)×106/L和(0.23±0.10)×106/L,染矽尘组的分别为(10.37±2.29)×106/L、(6.57±1.34)×106/L、(3.18±0.98)×106/L和(0.58±0.10)×106/L,MSC输注组的分别为(8.31±1.59)×106/L、(6.15±1.49)×106/L、(1.66±0.36)×106/L和(0.43±0.10)×106/L;染矽尘组和MSC输注组大鼠BALF的总细胞数、中性粒细胞和淋巴细胞计数均分别高于对照组(P<0.05),MSC输注组上述3个指标均低于染矽尘组(P<0.05)。3组血清ALT、AST、CK、LDH活力及BUN、Cr水平分别比较,差异均无统计学意义(P>0.05)。结论骨髓MSC对矽尘导致的肺部炎症及纤维化有潜在修复作用。
Objective To observe the repair effect of bone marrow mesenchymal stem cells (MSCs) on lung injury induced by silica dust in rats. Methods Seven MSCs from healthy male SD rats without specific pathogen were cultured and 30 SD rats were randomly divided into control group, silica dust group and MSC infusion group. In the control group, 1.0 ml of physiological sodium chloride solution was injected intratracheally and 1.0 ml of 40 g / L suspension of silica dust was injected intratracheally into the group of both the silica dust group and the MSC infusion group. Thereafter, the MSC infusion Rats in the tail vein of the rats were injected with 0.5 ml of MSC with a cell density of 5 × 10 9 / L, and the other two groups were injected with 0.5 ml of physiological sodium chloride solution in the caudal vein. The rats were sacrificed on the 28th day to observe the histopathological changes of the lung tissue. The lung coefficient, lung cell count (BALF), serum alanine aminotransferase (ALT), aspartate aminotransferase AST, creatine kinase (CK), lactate dehydrogenase (LDH) activity and BUN, creatinine (Cr) levels. Results Compared with the control group [(0.528 ± 0.044)% vs (0.435 ± 0.027)%, (0.492 ± 0.042)% vs (0.435 ± 0.027)%, P <0.05]. The coefficient of pulmonary organs in MSC infusion group was lower than that in silica group [(0.492 ± 0.042)% vs (0.528 ± 0.044)%, P <0.05]. Pathological examination showed that the control group had no pulmonary inflammation, changes of silicon nodules and fibrosis; the lung inflammation in rats exposed to silica dust group was the most serious, and a large number of silicon nodules and collagen fibers were seen. Compared with the silica dust group, Inflammation of the lungs in the MSC infusion group was reduced, the number of silicon nodules decreased, and the deposition area of collagen fibers was smaller. The total number of cells, the number of macrophages, neutrophils and lymphocytes in control group were (5.86 ± 1.28) × 106 / L, (5.45 ± 1.30) × 106 / L, (0.11 ± 0.04) × (10.37 ± 2.29) × 106 / L, (6.57 ± 1.34) × 106 / L, (3.18 ± 0.98) × 106 / L and And (0.58 ± 0.10) × 106 / L, respectively, and the MSC infusion group were (8.31 ± 1.59) × 106 / L, (6.15 ± 1.49) × 106 / L, ± 0.10) × 106 / L. The total cell count, neutrophil count and lymphocyte count of BALF in MSC group and siliceous dust group were higher than those in control group (P <0.05) All the three indexes were lower than that of the group with silica dust (P <0.05). The serum ALT, AST, CK, LDH activities and BUN and Cr levels in the three groups were not significantly different (P> 0.05). Conclusion Bone marrow MSCs potentially repair lung inflammation and fibrosis induced by silica dust.