Fig. 1

FGF19 induces a transient increase in mitochondrial number and an enhanced generation of ATP products. a Representative TEM images showing the changes of mitochondrial number in chondrocytes induced by FGF19 at 200 ng/ml in the presence of KLB (200 ng/ml). The images were chosen based on three independent experiments (n = 3). Orange arrows indicated individual mitochondrion. b Quantification of mitochondrial number (per cell) in chondrocytes induced by FGF19 at 200 ng/ml in the presence of KLB (200 ng/ml). Quantitative analyses of the mitochondrial number were based on nine cells (per group) from three independent experiments (n = 3). c Representative immunofluorescent staining showing the number changes of mitochondria in living chondrocytes induced by FGF19 (200 ng/ml) in the presence of KLB (200 ng/ml) for 72 h. The images were chosen based on three independent experiments (n = 3). Red, individual mitochondrion; Green, F-actin; Blue, nucleus. d Linear quantification of fluorescence intensity of mitochondrion number in chondrocytes induced by FGF19 at 200 ng/ml in the presence of KLB (200 ng/ml) by Image Pro Plus 6.0. e ATP assay showing the increase of intracellular ATP products in chondrocytes induced by FGF19 at 200 ng/ml in the presence of KLB (200 ng/ml). The results were based on three independent experiments (n = 3). f Representative western blotting showing the expression change of CS in chondrocytes induced by FGF19 at 200 ng/ml in the presence of KLB (200 ng/ml). The images were chosen based on three independent experiments (n = 3). g Quantification of CS by western blotting in (f). The data in b are shown as box (from 25, 50 to 75%) and whisker (minimum to maximum values) plots. The significant difference analysis in b, e and g was based on Student T-test