The homing of bone marrow mesenchymal stem cells transplanted via the trachea into rats exposed to silica dust / 中国组织工程研究

ABSTRACT

BACKGROUND:Bone marrow mesenchymal stem cels transplantationvia the trachea can relieve the lung injury of rats exposed to silica dust, but their distribution and migrationin vivois stil unclear. OBJECTIVE:To investigate the distribution and homing of bone marrow mesenchymal stem cels transplanted via the trachea into rats exposed to silica dust. METHODS: Bone marrow mesenchymal stem cels from Sprague-Dawley rats were isolated through bone marrow adherent method and transfected with lentivirus carrying enhanced green fluorescent protein gene (Lv-eGFP). Trypan blue staining and cel counting kit-8 were applied to assay the viability and proliferation of the transfected and untransfected cels. Sprague-Dawley rats, SPF level, were randomized into control group and silica dust exposure group. Rats in the two groups were respectively injectedvia the trachea with 1 mL of sterile silica dust suspensions (40 g/L) and 1 mL of normal saline. At 2 days after modeling, 2.2×106 transfected bone marrow mesenchymal stem cels were injected via the trachea into the rats of control group and silica dust exposure group. Rats were kiled at weeks 1, 2, 3, 4 after transplantation, and the distribution and intensity of green fluorescence in the lung, heart, liver, spleen, kidney, and brain tissue were observed under the fluorescence microscopy by frozen sections and analyzed using imaging analysis software. RESULTS AND CONCLUSION: When the multiplicity of infection was 50, there were no significant differences between the viability and proliferation activity of the transfected and untransfected cels (P > 0.05). After transplantation of transfected bone marrow mesenchymal stem cels, strong green fluorescence was observed widely in the lung, especialy around the bronchus and blood vessels, and stil obvious at the 4th week. The fluorescence of other organs also could be observed at the 1st week. It was strong and wide in the liver, spleen and heart, while faint and less in the kidney and brain, and al reduced with time. It shows bone marrow mesenchymal stem cels transplantedvia the trachea into rats exposed to silica dust can be homing to the injured lung of rats.