Figure 1.

FGF7 expression in the damaged liver is up-regulated around LPCs. (A) Liver sections prepared from DDC diet-fed mice were subjected to immunofluorescent double-staining analysis. Thy1⁺ cells (green) were observed in the immediate vicinity of CK19⁺ LPCs (red) during the course of LPC activation. Bars, 80 μm. (PV) Portal vein. (B) Thy1- and CK19-positive areas were increased in the DDC-treated livers, as determined by quantitative analysis of immunofluorescence-stained images. Mean ± SD (n = 3). (***) P < 0.001; (**) P < 0.01; (*) P < 0.05, compared with normal liver (0 wk). (C) Total RNA was isolated from whole-liver samples of normal diet-fed (0 wk) or DDC diet-fed mice, reverse-transcribed, and subjected to quantitative PCR analyses to determine expression of the LPC markers Epcam and Krt19, the mesenchymal cell marker Thy1, and Fgf7. Expression was normalized to that of Gapdh. Mean ± SD (n = 3). (***) P < 0.001; (**) P < 0.01; (*) P < 0.05, compared with the value at 0 wk. (D,E) Confocal immunofluorescence images of the livers show that FGF7 (green) protein localized in the proximity of EpCAM⁺ LPCs (D, red) and colocalized with Thy1⁺ mesenchymal cells (E, red) in the periportal region in injured livers. Bars, 50 μm. (PV) Portal vein. (F) Expression of FGF7 protein was increased in the DDC-treated livers, as determined by quantitative analysis of immunofluorescence-stained images of at least 11 periportal fields from three livers for each time point. Mean ± SE. (***) P < 0.001; (**) P < 0.01.