Abstract:

BACKGROUND: Allogeneic mesenchymal stem cells transplantation is widely used in clinics, but the required dose, duration and whether the side effects exists are still a research hotspot.
OBJECTIVE: To study the time- and dose-dependent immunomodulatory effect of allogeneic bone marrow mesenchymal stem cells in vivo. 
METHODS: Bone marrow-derived mesenchymal stem cells were isolated from mice with normal immune system. Twenty-four BALB/c mice were randomly divided into four groups. In experimental group, each mouse was injected with 0.3 mL cells suspension containing 5×10⁵, 5×10⁴, 5×10³ bone marrow-derived mesenchymal stem cells via the tail vein, respectively. In control group, the mice were only injected with 0.3 mL normal saline. The lymphocyte proliferation test, mixed lymphocyte reaction and experiments about the effect of bone marrow-derived mesenchymal stem cells transplantation on the immune system of allogeneic mice were performed and detected.
RESULTS AND CONCLUSION: After cell transplantation, bone marrow-derived mesenchymal stem cells exerted the in vivo immunomodulatory effect in a dose-dependent manner. Mesenchymal stem cells could promote the allogeneic graft implantation, and the immunomodulatory effect reached the peak at the 2nd week, gradually decreased at the 1st month and disappeared at the 2nd month. It is indicated that the immunomodulatory effects of mesenchymal stem cells are presented in a dose-dependent manner, which can only be maintained for some time.