Figure 6. Sphk1 is critical for UUO-induced kidney fibrosis in mice. (A) Sphk1 expression in kidney tissues of Tnfsf14+/+ mice after UUO surgery for 7 days was measured by immunohistochemistry (upper lane, original magnification ×200; lower lane, original magnification ×400). (B) Linear regression showed a close correlation between Sphk1 mRNA expression and Cola1 and Acta2 mRNA expression in kidney tissues of Tnfsf14+/+ mice after UUO surgery for 7 days. Spearman’s correlation coefficient and P value are shown (n = 10). (C–E) After UUO surgery, PF543 (1 mg/kg/day) was injected intraperitoneally for consecutive 7 days, and then kidney tissues were collected from each group. (C) Sirius Red and Masson staining of kidney tissues sections. Original magnification ×400. (D) α-SMA expression in kidney tissues was measured by immunohistochemistry. Original magnification ×200. (E) Western blot analyses of renal fibronectin and α-SMA protein in kidney tissues. Representative western blot (Left and quantitative data (Right) are presented. Sham group was used as the control of UUO. The data were representative of the results of three independent experiments. All values are represented as means ± SEM. n = 5 per group. ***P < 0.001.