Transplantation of MSCs Overexpressing HGF into a Rat Model of Liver Fibrosis

Abstract

Purpose: The aim of this study is to evaluate the effect of overexpressing human hepatocyte growth factor (HGF) for mesenchymal stem cells (MSCs) in liver fibrosis regeneration and magnetic resonance (MR) tracking of MSCs in rat liver.

Procedures: MSCs were transfected with ad-HGF/ad-green fluorescent protein (GFP) and labeled with superparamagnetic iron oxide (SPIO). The characteristics of SPIO-HGF/MSCs were investigated. Prussian blue staining for iron assessment was conducted in vitro and in vivo. SPIO-HGF/MSCs (group A) or SPIO-GFP/MSCs (group B) were transplanted into a rat model of liver fibrosis, and MR imaging of the rat liver was performed. The signal to noise ratio (SNR) and R2* (1/T2*) value were measured. Prussian blue staining was performed to detect the in vivo distribution of MSCs, and liver Ki67 immunohistochemistry (IHC) staining was studied. The serum levels of HGF, alanine aminotransferase (ALT) and hyaluronic acid (HA) were determined.

Results: The positive rate of HGF transfection was 93.17 % and the HGF/MSCs were labeled with SPIO successfully (97.80 ± 1.06 %). Labeling of MSCs with SPIO did not alter cell proliferation in vitro. The signal intensity of liver T2* WI images decreased on day 1 after cell transplantation and recovered to pre-transplantation level on day 15 (group A) and day 13 (group B). The SNR of group A were significantly lower than that of group B (P = 0.006), and the R2* values of group A were significantly higher than those of group B (P < 0.001). The R2* value had a significantly negative correlation with SNR. There were more Prussian blue-positive cells in of group A were more than in group B in vivo. The positive rate of Ki67 was 16.11 ± 2.13 %, and the serum level of ALT/HA was decreased in group A.

Conclusion: HGF transfection improved MSCs localization in the liver and aided liver repair. The R2* value might be a feasible index in addition to SNR to track the SPIO-MSC transplantation in the liver.

Keywords: Hepatocyte growth factor; Liver fibrosis; Magnetic resonance imaging; Mesenchymal stem cells; Superparamagnetic iron oxide.