BACKGROUND:Most bone marrow mesenchymal stem cel s are infused intravenously and have very low efficiency of homing to the bone marrow. However, cel infusion via the femoral approach is little reported. OBJECTIVE:To explore the distribution of luciferase gene modified red fluorescent protein transgenic bone marrow mesenchymal stem cel s in vivo through different infusion routes. METHODS:Luciferase gene modified bone marrow mesenchymal stem cel s at different gradients (5×106, 1×106, 1×105, 1×104) were seeded or injected into the in vitro pore plate or free femurs to observe the fluorescence imaging and select the best concentration of cel s. Luciferase gene modified bone marrow mesenchymal stem cel s at the best cel concentration were injected into the mice via the femur and the tail vein, respectively. The distribution of fluorescence and cel number in the mice were explored by using bioluminescence, pathological examination, flow cytometry and quantitative PCR. RESULTS AND CONCLUSION:Ex vivo fluorescence intensity of luciferase gene modified bone marrow mesenchymal stem cel s was positively correlated with the cel concentration;fluorescent cel s in vivo appeared in the femur first and then quickly spread to the lungs in the femur group, while fluorescent cel s in the tail vein group spread to the lungs quickly after cel infusion. Fluorescent cel s could be seen in the spleen, liver and other organs 24 hours later in the two groups. The distribution and migration of cel s in mice could be observed successful y by bioluminescence;5 minutes after cel infusion, the lungs of mice in the two groups began to emit fluorescence that could spread to the liver, spleen and other tissues 24 hours later, and the fluorescence intensity reached its peak after 15 minutes. The distribution of bone marrow mesenchymal stem cel s in mice had no significant difference between the femur group and the tail vein group. To conclude, cel injection through the bone marrow cavity and tail vein fails to promote the homing of bone marrow mesenchymal stem cel s to the bone marrow.