Objective: To evaluate the efficacy of in vivo magnetic resonance imaging (MRI) of mesenchymal stem cells (MSCs) injected intravascularly in treatment of acute renal failure (ARF) , and to investigate the changes of renal function and pathology of ARF after MSC transplantation.
Methods: Rat MSCs were isolated and labeled with Fe2O3-PLL in vitro. Thirty SD rats underwent intramuscular injection of glycerol so as to establish ARF models and then randomly divided into 3 equal groups: Group I undergoing injection of labeled MSCs into abdominal aorta via transcatheter, Group II injected with unlabelled MSCs, and Group III injected with normal saline as controls. MRI of kidney was conducted before injection, and 0.5 h, and 1, 2, and 5 days after injection. One and 2 days after the transplantation 3 rats from each group underwent MRI and extraction of blood samples from the abdominal aorta and then killed with their kidneys taken out, and 5 days after the rest rats were all killed after MRI with their kidneys taken out. Serum creatinine (Scr) and blood urea nitrogen (BUN) were examined so as to evaluate the renal function. Microscopy was conducted to observe the pathological changes. Prussian blue + CD68 antibody staining was performed to identify the labeled MSCs.
Results: MRI showed decrease of signal intensity in renal cortex on the T2 *-weighted MR images up to 5 days after transplantation. Histological analysis showed that most Prussian blue-positive cells were in the glomerular capillaries, corresponding to the areas where signal intensity decrease was observed by MRI. The Scr and BUN levels 2 and 5 days after the implantation of Group I were both lower than those of the control group, and there were not significant differences in the Scr and BUN levels between Groups I and II. Renal tubular injury scoring showed that the renal tubular injury was significantly lighter than that of the control group.
Conclusion: 1.5-T MRI seems a good in vivo technique to monitor the magnetically labeled MSCs administered into the abdominal aorta of ARF animals, which are distributed in the glomerular capillaries in the early stage after transplantation. MSCs may promote the recovery of ARF.