Figure 4.

Inhibition of fibroblast growth factor 23 (FGF23) signaling decreases Fgf23 expression and circulating levels induced by lipopolysaccharide (LPS). C57BL/6J wild-type mice were injected intraperitoneally (i.p.) with C-tail FGF23 (1 mg/kg, indicated as FGF23 BL) or vehicle (HEPES buffer) for 8 hours (h). Mice were then challenged with LPS (i.p. 50 mg/kg) or vehicle (0.9% NaCl) for 4 h. (A) Quantitative real-time polymerase chain reaction (qRT-PCR) for Fgf23 expression in bone. Data are expressed as fold change (2-DDCt) relative to housekeeping gene Gapdh. (B and C) Serum concentration of (B) C-terminal FGF23 (cFGF23) and (C) intact FGF23 measured by ELISA. Samples were measured in duplicates (n=5-7 per group). Data are represented as mean+standard deviation. All data were analyzed for normality with Shapiro-Wilk test and equivalence of variance using Levene’s test. Because the samples did not show normal distribution, data were aligned in RANK transformation, and confirmed for normality. As the samples showed normal distribution, two-way ANOVA was performed with Bonferroni’s multiple comparison test. Ctl: control (vehicle), ns: not significant, *P<0.05, **P<0.01, ***P<0.001.