A: The expression of p-ERK in mouse cholangiocytes (mean ± SD, n = 3), *P<0.05 vs. WT, #P<0.05 vs. BDL. B: Immunofluorescence for p-ERK (co-stained with CK19) in frozen liver sections (n=3), upper three panels: Orig. magn. ×40, scale bar 50 μm; lower panel: Orig. magn. ×40 zoom5, scale bar 10 μm (red CK19, green p-ERK, blue DAPI). C: The expression of p-ERK in cholangiocytes from apelin−/− BDL mice (mean ± SD, n = 3), *P<0.05 vs. WT, #P<0.05 vs. BDL. D: Expression of p-ERK in apelin treated HIBEpiCs (mean ± SD, n = 3), *P<0.05 vs. Control, #P<0.05 vs. apelin-13. E: The measurement of proliferation in apelin treated HIBEpiCs by MTS (mean ± SD, n = 3), *P<0.05 vs. Control, #P<0.05 vs. apelin-13. F: The mRNA expression of PCNA and KI67 in apelin treated HIBEpiCs (mean ± SD, n = 3), *P<0.05 vs. Control, #P<0.05 vs. apelin-13.