Supplementary Material for: The Inhibitory Effect of Eplerenone on Cell Proliferation in the Contralateral Kidneys of Rats with Unilateral Ureteral Obstruction

Background: The unilateral ureteral obstruction (UUO)
model not only induces renal interstitial fibrosis in the obstructed
kidney but also induces injury in the contralateral kidney. We
hypothesized that activation of the mineralocorticoid receptor (MR) may
induce fibrosis in the early stage of UUO. Methods: Thirty
male Sprague-Dawley rats weighting 200 ± 10 g were used in this study
and randomly divided into 3 groups: a UUO group, a UUO and eplerenone
group, and a sham group. The contralateral kidney and plasma were
harvested for further study 10 days after surgery. Results:
The level of plasma aldosterone (869.95 ± 55.851 pg/mL) was
significantly higher in the UUO group than that in the sham group
(478.581 ± 36.186 pg/mL vs. UUO, p < 0.05). The infiltrated
inflammatory cells (F4/80) and deposited collagens were increased
significantly in the contralateral kidneys in the UUO group compared to
those in the sham group, which were decreased by eplerenone. However,
proliferating cell nuclear antigen was increased 2.47 times in the UUO
group compared to the sham group in the contralateral kidney (p
< 0.01), and those changes are attenuated by eplerenone. The
expression of SGK-1 protein and mRNA was upregulated in the
contralateral kidney in the UUO group, which is suppressed by eplerenone
treatment. NF-κB pathway effecters were also changed markedly in the
contralateral kidney in the UUO group and partly reversed by eplerenone.
Conclusion: Aldosterone induces inflammatory cell
proliferation via the MR/SGK-1 and NF-κB pathways and eventually leads
to fibrosis in the contralateral kidney.

背景：单侧输尿管梗阻（unilateral ureteral obstruction, UUO）模型不仅可在梗阻侧肾脏诱导肾间质纤维化，还可对健侧肾脏造成损伤。本研究推测，盐皮质激素受体（mineralocorticoid receptor, MR）的激活可能在UUO早期诱导纤维化发生。
方法：本研究选用30只体重为200±10 g的雄性Sprague-Dawley（SD）大鼠，随机分为3组：UUO模型组、UUO+依普利酮（eplerenone）组以及假手术组。于术后10天采集健侧肾脏及血浆样本，用于后续实验研究。
结果：UUO模型组大鼠血浆醛固酮水平（869.95±55.851 pg/mL）显著高于假手术组（478.581±36.186 pg/mL，p<0.05）。与假手术组相比，UUO模型组健侧肾脏中浸润的炎症细胞（F4/80标记）及沉积的胶原显著增多，而依普利酮可抑制上述病理变化。此外，UUO模型组健侧肾脏的增殖细胞核抗原（proliferating cell nuclear antigen）表达量较假手术组升高2.47倍（p<0.01），该变化同样可被依普利酮缓解。UUO模型组健侧肾脏中SGK-1蛋白及mRNA的表达均上调，而依普利酮治疗可抑制该上调现象。UUO模型组健侧肾脏的NF-κB通路效应分子亦发生显著改变，且该改变可被依普利酮部分逆转。
结论：醛固酮可通过MR/SGK-1及NF-κB通路诱导炎症细胞增殖，最终导致健侧肾脏发生纤维化。