Figure 2.
Spontaneous development of kidney fibrosis in heterozygous vascular endothelial growth factor receptor type 2 (VEGFR2)+/− mice. Wild-type (WT) and VEGFR2+/− mice were fed with normal rodent chow, and 48 mice were enrolled and randomly assigned into each group. Six mice per group were euthanized at the age of 6, 12, 24, and 52 wk. The plasma and kidneys were collected for further experiments. A: plasma creatinine (Cr) and phosphate (Pi). B: kidney fibrosis was assessed with trichrome staining. Representative microscopic images of mice from each group from 6 to 52 wk old are shown. Scale bar = 50 µm. C: quantitative analysis of kidney fibrosis based on trichrome-stained kidney sections with ImageJ software. D: quantitative analysis of CD31 mRNA in the kidneys with quantitative PCR. Data in A, C, and D are expressed as means ± SD of at least four mice from each group at the age of 6–52 wk. Statistical analysis was evaluated by an unpaired Student’s t test, and significance was accepted when *P < 0.05 and **P < 0.01 between two groups at same age. The results shown in A, C, and D are presented as mixed sexes. E: immunoblot analysis for endothelial marker (CD31), Klotho, α-smooth muscle actin (α-SMA), connective tissue growth factor (CTGF), and β-actin in total kidney lysates from two genotyped mice at 6 and 12 wk old. E, left: representative immunoblots. E, right: quantitative analysis of all immunoblots from each group. E: quantitative data are expressed with scatterplots of individual data points (open circles indicate male mice and pink circles indicate female mice) and means ± SD (bars and errors). Statistical significance was evaluated by two-way ANOVA followed by a Student–Newman–Keuls test. Statistical significance was accepted when *P < 0.05 and **P < 0.01 between two groups. The sample number in each group is presented in parentheses underneath each corresponding bar. VR2, VEGFR2.