Distribution of mesenchymal stem cells in mdx mice after transplantation

AIM: To investigate the distribution of mesenchymal stem cells in mdx mice after transplantation. METHODS: P5 mesenchymal stem cells (MSCs) of SD rats labeled with ［3H］－TdR were injected intravenously into the mdx mice preconditioned with 7 Gy γ ray. The mice were killed at 24 h, 48 h, 2 weeks, 1 month, 2 months, 4 months after transplantation of MSCs. Blood, lung, liver, bone marrow, heart, and skeletal muscle were collected, then the irradiated quantity was detected to calculate tissue specific localization account using scintillascope. RESULTS: Specific localization account in lung was the highest at 24 h. At 48 h liver was the highest. After transplantation the account of bone marrow increased and at 2 weeks reached the highest, then decreased as time going but was still higher than that of other organs. The account of skeletal muscle and heart also increased. CONCLUSION: At early time after transplantation, the MSCs labeled by ［3H］－TdR mainly distribute in lung and liver, then homing to bone marrow increasingly and the account is the highest at 2 weeks. MSCs migrate to injured organs, such as skeletal muscle and heart. The migration suggests that MSCs can settle down in muscles and provide evidence for MSCs to differentiate into myocytes.