Proximal Tubular Development Is Impaired with Downregulation of MAPK/ERK Signaling, HIF-1α, and Catalase by Hyperoxia Exposure in Neonatal Rats

Figure 7

Neonatal hyperoxia downregulates hypoxia-inducible factor 1α (HIF-1α) and catalase expression in mature proximal tubules. (a) Expression bands of HIF-1α and catalase in mature kidneys exposed to neonatal normoxia or hyperoxia as detected by western blotting. Relative expression adjusted to the reference gene GAPDH and then standardized to the value of the normoxia group on P30D is shown by box and whisker plots. The whiskers represent the minimal or the maximal gray value, and the boxes span the interquartile range of measurements for 10 rats with the mean value of 3 replicates (). , one-way ANOVA, Bonferroni post hoc test. (b) HIF-1α and catalase expression in the proximal tubules of adult rats exposed to neonatal normoxia or hyperoxia as detected by immunohistochemical staining (original magnification ×400; scale bar, 100 μm). (c) The immunostaining intensity of HIF-1α expression in the proximal tubules of adult rats exposed to neonatal normoxia or hyperoxia is shown by box and whisker plots. Relative expression is standardized to the value of the normoxia group on P30D. The whiskers represent the minimal intensity or the maximal intensity, and the boxes span the interquartile range of measurements for 10 rats and a mean value of 10 separate fields of view (). , one-way ANOVA, Bonferroni post hoc test. (d) The immunostaining intensity of catalase expression in the proximal tubules of adult rats exposed to neonatal normoxia or hyperoxia is shown by box and whisker plots. Relative expression is standardized to the value of the normoxia group on P30D. The whiskers represent the minimal intensity or the maximal intensity, and the boxes span the interquartile range of measurements for 10 rats and a mean value of 10 separate fields of view (). , one-way ANOVA, Bonferroni post hoc test.

(a)

(b)

(c)

(d)