In vivo MR imaging of magnetically labeled mesenchymal stem cells transplanted into rat liver through hepatic arterial injection.
OBJECTIVE
The aim of this study was to evaluate in vivo magnetic resonance imaging (MRI) for tracking the magnetically labeled mesenchymal stem cells (MSCs) transplanted into rat liver through hepatic arterial injection.


METHODS
MSCs, harvested from the bone marrow of Wistar rats and expanded by the adhesion method, were labeled with both Feridex and 4',6-diamidino-2-phenylindole (DAPI). Cell transplantation was performed by injection of 1 x 10(6) labeled cells (n = 20) or unlabeled cells (n = 10) via hepatic artery into rat livers treated with 2% carbon tetrachloride to induce acute liver necrosis. MR imaging was performed on a clinical 1.5 T MR scanner with a T(2)*-weighted gradient-echo sequence immediately before and at 1 h, 3 days, 7 days and 14 days after transplantation, and the signal-to-noise ratios (SNRs) were measured in liver, spleen, kidney and muscle. After MR examination, the animals were sacrificed, and the liver, kidney, lung and muscle were prepared for fluorescence observation and Prussian Blue staining.


RESULTS
In the group treated with labeled cells, the SNR of the liver after cell transplantation was 3.12 +/- 0.43 at 1 h, 7.98 +/- 1.05 at 3 days and 11.46 +/- 1.41 at 7 days. These values were significantly lower than the pre-transplantation SNR (14.40 +/- 0.37). In the group treated with unlabeled cells, no significant difference could be found between after and before transplantation liver SNRs. Prussian Blue staining showed iron particles, contained within the cytoplasm and distributed in the liver parenchyma, which corresponded to the DAPI-stained fluorescent nuclei under the fluorescence microscope.


CONCLUSIONS
The magnetically labeled MSCs transplanted into rat liver through hepatic arterial injection can be detected and monitored in vivo with a 1.5 T clinical MR scanner for up to 7 days after cell transplantation.
Cai
Jinhua
J
Department of Radiology, Children's Hospital, Chongqing Medical University, Chongqing, 400014, China. cjh710506@tom.com
Zhang
Xuemei
X
Wang
Xin
X
Li
Chuan
C
Liu
Guanxin
G
D000818:Animals; D002251:Carbon Tetrachloride; D003287:Contrast Media; D003911:Dextrans; D004195:Disease Models, Animal; D052203:Ferrosoferric Oxide; D007089:Image Enhancement / Q000379:methods*; D007269:Injections, Intra-Arterial; D007501:Iron; D008099:Liver / Q000473:pathology* / Q000601:surgery; D017114:Liver Failure, Acute / Q000139:chemically induced / Q000473:pathology* / Q000601:surgery; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles; D045164:Mesenchymal Stem Cell Transplantation / Q000379:methods*; D059630:Mesenchymal Stem Cells / Q000473:pathology*; D010087:Oxides; D051381:Rats; D017208:Rats, Wistar; D013194:Staining and Labeling / Q000379:methods; D016896:Treatment Outcome
D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; D002251:Carbon Tetrachloride; D007501:Iron; C065507:ferumoxides; D052203:Ferrosoferric Oxide