Upregulation of Cortical Renin and Downregulation of Medullary (Pro)Renin Receptor in Unilateral Ureteral Obstruction

Figure 1. Unilateral ureteral obstruction (UUO) induces a pro-inflammatory and pro-fibrotic phenotype at 7 days. (A) IL-1β and (B) TGF-β1 mRNA levels in the left and right kidneys. 18S mRNA was used as the housekeeping gene. One-way ANOVA test followed by Bonferroni test was performed. **P 0.01 and ***P 0.001 vs. Sham group. ### P 0.001 vs. UUO left kidney group (n = 5).

Figure 2. Unilateral ureteral obstruction (UUO) induces tubular remodeling in the renal cortex and medulla after 7 days. (A) Haematoxylin–eosin staining in the renal cortex and medulla (scale bar, 100 µm). Black arrows show the increase of tubule interstitial space, while black asterisks show tubular dilation. Quantification of tubule diameter in the (B) cortex and (C) medulla of Sham and UUO groups. Mann–Whitney statistic test. *P 0.05 vs. Sham group (n = 5).

Figure 3. Unilateral ureteral obstruction (UUO) induces upregulation of renin in left renal cortex. (A) mRNA levels for: angiotensinogen (AGT), renin, angiotensin-converting enzyme (ACE)1/2, (pro)renin receptor (PRR), and angiotensin-II receptor type 1 (AT1R) in the renal cortex. 18S mRNA was used as the housekeeping gene in qRT-PCR studies. Western blot and immunodetection of (B) renin and (C) ACE1 in the renal cortex. α-tubulin was used as internal loading control. Student’s t test was performed. **P < 0.01 or ***P < 0.001 vs. Sham group (n = 5).

Figure 4. UUO induces downregulation of (pro)renin receptor (PRR) in left renal medulla. (A) mRNA levels for: AGT, renin, ACE1/2, PRR, and AT1R in renal medulla. 18S mRNA was used as the housekeeping gene in qRT-PCR studies. Western blot and immunodetection of (B) AGT and (C) PRR in renal medulla. α-tubulin was used as internal loading control. Student’s t test was performed. *P < 0.05 or **P < 0.01 vs. Sham group (n = 5).

Figure 5. Proposal of changes in intrarenal renin–angiotensin system (iRAS) components during the inflammatory stage of UUO. Obstructive uropathy at 7 days (recognized as “the pro-inflammatory phase”) induces tubular remodeling and iRAS activation in the cortex, as reflected by the renin increase in dilated tubules. This activation may be counteracted by the iRAS components in the medulla, particularly by PRR.