目的了解骨髓间充质干细胞(BMMSC)在染矽尘大鼠体内的分布情况。方法取7只无特定病原体级健康雄性SD大鼠采用全骨髓贴壁法分离培养BMMSC,经慢病毒载体介导的增强型绿色荧光蛋白(LV-e GFP)转染后,采用台盼蓝染色和CCK-8法检测转染前后细胞的活力及增殖能力。取同批大鼠随机分为对照组和染尘组,每组4只。染尘组以1.0mL质量浓度为40 g/L的矽尘混悬液气管内注入染尘,对照组气管内注入1.0mL生理氯化钠溶液。以转染后的BMMSC经尾静脉注入2组大鼠体内,分别于移植后第1、2、3和4周取肺、肝、脾、心、肾脏和脑组织冰冻切片,荧光显微镜下观察转染LV-e GFP的BMMSC植入后在上述脏器组织的荧光分布,采用Image-pro plus 6.0图像分析软件计算组织荧光强度。结果感染复数为50时,BMMSC转染率达80.00%,绿色荧光表达强烈、持续,转染后BMMSC形态无改变;转染与未转染LV-e GFP的BMMSC的细胞存活率差异无统计学意义[(97.67±0.60)%vs(98.03±0.56)%,P>0.05]。BMMSC增殖能力在LV-e GFP转染处理的主效应上无统计学意义(P>0.05)。植入转染LV-e GFP的BMMSC后第1周,2组大鼠各脏器组织切片镜下均可见荧光分布,其中染尘组大鼠肺脏组织切片各视野均可见较强荧光,持续至植入后第4周,以气管、血管及其周围组织荧光明显,肺泡及肺间质荧光也分布较多。植入转染LV-e GFP的BMMSC后,染尘组大鼠肺脏组织4个观察时间点荧光强度均高于同时间点对照组(P<0.01),且随观察时间的延长而减弱(P<0.01);染尘组大鼠肝脏和心脏组织4个观察时间点以及肾脏组织第2、3和4周的荧光强度均低于同时间点对照组(P<0.01);染尘组大鼠脾脏组织第1和2周的荧光强度均高于同时间点对照组(P<0.01),第3和4周的荧光强度均低于同时间点对照组(P<0.01);染尘组大鼠脑组织第1周的荧光强度高于同时间点对照组(P<0.01)。染尘组大鼠肺脏组织第1和2周荧光强度均高于同组同时间点肝脏、肾脏和脑组织(P<0.01),低于脾脏组织(P<0.01);但第3和4周荧光强度均高于同组同时间点其余5种器官组织(P<0.01)。结论 BMMSC进入染矽尘大鼠体内后可归巢并定植到受损肺部。 Objective To investigate the distribution of bone marrow-derived mesenchymal stem cells (BMMSCs) in rats exposed to silica dust. Methods Seven healthy male Sprague-Dawley (SD) rats without specific pathogen were isolated and cultured by whole bone marrow adherent method. After transfection with lentiviral vector-mediated enhanced green fluorescent protein (LV-e GFP), BMMSCs were stained with trypan blue And CCK-8 assay before and after transfection cell viability and proliferation. Take the same batch of rats were randomly divided into control group and dyed group, 4 in each group. Dust group with 1.0mL mass concentration of 40g / L of silica dust suspension into the tracheal injection of dust, the control group, intratracheal injection of 1.0mL physiological sodium chloride solution. The transplanted BMMSCs were injected into the tail vein of two groups of rats, and the frozen sections of lung, liver, spleen, heart, kidney and brain were taken at 1, 2, 3 and 4 weeks after transplantation, respectively. Fluorescence distribution of BMMSCs stained with LV-e GFP in the above organs was calculated using Image-pro plus 6.0 image analysis software to calculate tissue fluorescence intensity. Results When the number of infected cells was 50, the transfection rate of BMMSC was 80.00% and the green fluorescence was strong and persistent. There was no change in the morphology of BMMSCs after transfection. There was no significant difference in cell viability between BMMSCs transfected with LV-e GFP and untransfected cells Significance [(97.67 ± 0.60)% vs (98.03 ± 0.56)%, P> 0.05]. The main effect of BMMSC proliferation on LV-e GFP transfection was not statistically significant (P> 0.05). At the first week after BMMSC transfection with LV-e GFP, the fluorescence distributions were observed under the microscope of the organs of the two groups. In each group, the fluorescence of the lung tissue sections of the dust-exposed group showed strong fluorescence, In the fourth week after implantation, the fluorescence in the trachea, blood vessels and their surrounding tissues was obvious, and the fluorescence in the alveoli and lung interstitium was also distributed more. Fluorescence intensity at 4 observation time points in the lung tissue of the dust-exposed group was significantly higher than that of the point-control group (P <0.01) after implanted with BM-MSCs transfected with LV-e GFP, and decreased with time (P <0.01). The fluorescence intensity of liver and heart in 4 groups and the fluorescence intensity in 2, 3 and 4 weeks were lower than those in the control group (P <0.01) The fluorescence intensity of spleen at 1 and 2 weeks was higher than that of the control group at the same time (P <0.01), and the fluorescence intensity at 3 and 4 weeks was lower than that of the control group at the same time point (P <0.01) Fluorescence intensity of brain tissue in the first week was higher than that in the control group at the same time point (P <0.01). The fluorescence intensity of the lungs in the dust-exposed group was higher than that in the liver, kidney and brain (P <0.01) at the same time point in the same group, but lower than that in the spleen (P <0.01) Fluorescence intensity was higher than the same group at the same time the remaining five kinds of organ tissue (P <0.01). Conclusion BMMSC can be homing and colonizing damaged lungs after entering the body of rats exposed to silica dust.