Inhibitory effects of Eplerenone on angiogenesis via modulating SGK1/TGF-ß pathway in contralateral kidney of CKD pregnancy rats.

BACKGROUND: Eplerenone is a selective aldosterone receptor blocker that is effective in preventing the progression of chroinic kidney disease (CKD). However, its mechanism and role in CKD pregnancy still remain uncertain. The aim of this study was to evaluate whether eplerenone could attenuated the fibrosis of unilateral ureteral obstruction (UUO) pregnant rats' contralateral kidney, improved pregnancy outcome and explore its therapeutic mechanisms. METHODS: A pregnancy rat model of UUO established, female Wistar rats were randomly assigned into sham-operated group (Sham group),sham-operated combined pregnancy group (SP group), unilateral ureteral obstruction combined pregnancy group (UUO + Pregnancy group), unilateral ureteral obstruction combined pregnancy, administered eplerenone (UUO + Pregnancy+Eplerenone group). On the 18th day of pregnancy, the rats were placed in a metabolic cage, 24 h urine was collected and stored at -80 °C. Next day, all animals were euthanized, and serum was collected by centrifugation and stored at -20 °C. Then the right kidney was extracted, a part of the kidney was placed in 4% paraformaldehyde for morphology, immunohistochemical staining, and immunofluorescence staining, and the other part was placed in a - 80 °C refrigerator for RNA and protein extraction. In vitro, HUVECs was treated with aldosterone, progesterone and estradiol, VEGFA and its receptor blocker bevacizumab. The ability of proliferation, migration and tubularization of HUVECs was detected by CCK-8, scratch wound assay and endothelial tube formation assay. And the co-expression of CD34 and α-SMA of HUVECs was detected by Flow cytometry. RESULTS: Immunofluorescence results showed that the co-expression of CD34 and α-SMA increased in the UUO + Pregnancy group was significantly increased. The expression of SGK-1, TGFß-1, Smad2, Smad3, VEGF-A, VEGFR2, CD34, α-SMA and Collagen I was significantly higher in the kidneys of the UUO + Pregnancy group compared to the Sham group and SP group. Eplerenone inhibited the expression of those results. In vitro, the ability of proliferation, migration and tubularization was increased after treated with aldosterone, aldosterone with progesterone and estradiol or VEGFA. Similarly, the expression of α-SMA on the surface of HUVECs treated with aldosterone, aldosterone with progesterone and estradiol were increased, while eplerenone supressed its expression. CONCLUSION: Eplerenone inhibits renal angiogenesis by blocking the SGK-1/TGFß signal transduction pathway, thereby inhibiting the phenotypic transformation of endothelial cells, slowing down renal fibrosis, and reducing kidney damage caused by pregnancy.

Esaxerenone Attenuates Aldosterone-Induced Mitochondrial Damage-Mediated Pyroptosis in Mouse Aorta and Rat Vascular Smooth Muscle Cells.

BACKGROUND: Vascular smooth muscle cell (VSMC) injury caused by the inflammatory response plays a key role in cardiovascular disease (CVD), and the vasoprotective effects of mineralocorticoid receptor blockers (MRBs) support the role of mineralocorticoid receptor (MR) activation. METHODS: C57BL/6 mice and VSMCs isolated from rats were treated with aldosterone and esaxerenone. Caspase-1, GSDMD-N, IL-1ß, and NR3C2 expression and DNA damage in aortic VSMCs were detected using immunohistochemistry, Western blotting, and TUNEL staining. Mitochondrial changes were detected by transmission electron microscopy (TEM). Reactive oxygen species (ROS), MitoTracker, JC-I, mitochondrial respiratory chain complexes I-V, and NR3C2 were detected using immunofluorescence and flow cytometry. Pyroptosis was detected with scanning electron microscopy (SEM). RESULTS: After aldosterone treatment, the number of TUNEL-positive cells increased significantly, and the expression of caspase-1, GSDMD-N, and IL-1ß increased. TEM revealed mitochondrial damage, and SEM revealed specific pyroptotic changes, such as cell membrane pore changes and cytoplasmic extravasation. Increased ROS levels and nuclear translocation of NR3C2 were also observed. These pyroptosis-related changes were reversed by esaxerenone. CONCLUSIONS: Aldosterone activates the MR and mediates mitochondrial damage, thereby inducing pyroptosis in VSMCs via the NLRP3/caspase-1 pathway. Esaxerenone inhibits MR activation and reduces mitochondrial damage and oxidative stress, thereby inhibiting pyroptosis.

Eplerenone reduces lymphangiogenesis in the contralateral kidneys of UUO rats.

Inflammation and fibrosis often occur in the kidney after acute injury, resulting in chronic kidney disease and consequent renal failure. Recent studies have indicated that lymphangiogenesis can drive renal inflammation and fibrosis in injured kidneys. However, whether and how this pathogenesis affects the contralateral kidney remain largely unknown. In our study, we uncovered a mechanism by which the contralateral kidney responded to injury. We found that the activation of mineralocorticoid receptors and the increase in vascular endothelial growth factor C in the contralateral kidney after unilateral ureteral obstruction could promote lymphangiogenesis. Furthermore, mineralocorticoid receptor activation in lymphatic endothelial cells resulted in the secretion of myofibroblast markers, thereby contributing to renal fibrosis. We observed that this process could be attenuated by administering the mineralocorticoid receptor blocker eplerenone, which, prevented the development of fibrotic injury in the contralateral kidneys of rats with unilateral ureteral obstruction. These findings offer valuable insights into the intricate mechanisms underlying kidney injury and may have implications for the development of therapeutic strategies to mitigate renal fibrosis in the context of kidney disease.

Esaxerenone Inhibits Interferon-γ Induced Pyroptosis of Macrophages in the Lungs of Aldosterone-treated Mice.

Lung immune cells such as lymphocytes and macrophages can induce an inflammatory response due to the activation of mineralocorticoid receptor (MR), which is manifested by the infiltration of inflammatory cells and the secretion of inflammatory cytokines and subsequent apoptosis, pyroptosis and necrosis of intrinsic lung cells and immune cells. Macrophages are immune cells that are abundant in the lung and act as the first line of defense against pathogens but are also aggravating factors of infection. The activation of the renin-angiotensin-aldosterone system (RAAS), especially aldosterone-stimulated MR activation, can induce macrophage and CD8+ T cell aggregation and the secretion of cytokines such as tumor necrosis factor-α (TNF-α) and interferon-gamma (IFN-γ). Increased IFN-γ secretion can induce macrophage pyroptosis and the release of interleukin 1-ß (IL-1ß), aggravating lung injury. In this study, lung injury in C57BL/6 mice was induced by subcutaneous micro-osmotic pump infusion of aldosterone. After 12 weeks of administration, the kidney, heart, blood vessels and lungs all showed obvious inflammatory injury, which manifested as rapid accumulation of macrophages. The overexpression of IFN-γ in the lungs of aldosterone-treated mice and the stimulation of MH-S and RAW264.7 alveolar macrophages (AMs) with aldosterone in vitro showed that IFN-γ induced pyroptosis of macrophages via the activation of the inflammasome, and the MR blocker esaxerenone effectively inhibited this effect and alleviated lung injury. In addition, IFN-γ secreted by CD8+ T cells is associated with macrophage pyroptosis. In conclusion, the inhibition of macrophage pyroptosis can effectively alleviate lung injury.

Esaxerenone Inhibits Renal Angiogenesis and Endothelial-Mesenchymal Transition via the VEGFA and TGF-ß1 Pathways in Aldosterone-Infused Mice.

Renal fibrosis is an inevitable process in the progression of chronic kidney disease (CKD). Angiogenesis plays an important role in this process. Vascular endothelial cells are involved in renal fibrosis by phenotypic transformation and secretion of extracellular matrix. Aldosterone stimulates mineralocorticoid receptor (MR) activation and induces inflammation, which is important for angiogenesis. Clinically, MR blockers (MRBs) have a protective effect on damaged kidneys, which may be associated with inhibition of angiogenesis. In this study, we used aldosterone-infused mice and found that aldosterone induced angiogenesis and that endothelial-mesenchymal transition (EndMT) in neovascular endothelial cells was involved in renal fibrosis. Notably, aldosterone induced inflammation and stimulated macrophages to secrete vascular endothelial growth factor (VEGF) A to regulate angiogenesis by activating MR, whereas EndMT occurred in response to transforming growth factor-ß1 (TGF-ß1) induction and participated in renal fibrosis. These effects were antagonized by the MRB esaxerenone. These findings suggest that reducing angiogenesis may be an effective strategy for treating renal fibrosis.

Eplerenone inhibits the macrophage-to-myofibroblast transition in rats with UUO-induced type 4 cardiorenal syndrome through the MR/CTGF pathway.

Cardiovascular complications are the leading causes of death in patients with chronic kidney disease (CKD), accounting for approximately 50% of deaths. Despite significant advances in the understanding of cardiac disease due to CKD, the underlying mechanisms involved in many pathological changes have not been fully elucidated. In our previous study, we observed severe fibrosis in the contralateral kidney of a 6-month-old rat UUO model. In the present experiment, we also observed severe fibrosis in the hearts of rats subjected to UUO and the macrophage-to-myofibroblast transition (MMT). These effects were inhibited by the mineralocorticoid receptor (MR) blocker eplerenone. Notably, in vitro, aldosterone-activated MR induced the MMT and subsequently promoted the secretion of CTGF, the target of MR, from macrophages; these changes were inhibited by eplerenone. The CTGF also induced the MMT and both the aldosterone and CTGF-induced MMT could be alleviated by the CTGF blocker. In conclusion, our results suggest that targeting the MR/CTGF pathway to inhibit the MMT may be an effective therapeutic strategy for the treatment of cardiac fibrosis.

Eplerenone Prevents Cardiac Fibrosis by Inhibiting Angiogenesis in Unilateral Urinary Obstruction Rats.

Introduction: Cardiovascular disease constitutes the leading cause of mortality in patients with chronic kidney disease (CKD), which is termed cardiorenal syndrome type 4 (CRS-4). Here, we report the development of pathological cardiac remodeling and fibrosis in unilateral urinary obstruction (UUO) rats. Methods: Hematoxylin and eosin (H&E) staining was performed to observe the pathology of myocardial tissue. The degree of myocardial tissue fibrosis was observed by Masson and Sirius red staining. Immunohistochemical staining was applied to detect the expression of CD34 and CD105 in myocardial tissue, and immunofluorescent staining was performed to examine the expression of CD34, collagen I/collagen III, and alpha smooth muscle actin (α-SMA). The expression of the signal pathway-related proteins vascular endothelial growth factor A (VEGFA), vascular endothelial growth factor receptor 2 (VEGFR2), nuclear factor κB (NF-κB), and interleukin (IL)-1ß was tested by western blotting. Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the mRNA levels of serum and glucocorticoid-inducible kinase (SGK)-1, NF-κB, and interleukin-1ß (IL-1ß). Results: The results showed the development of pathological cardiac remodeling and cardiac dysfunction in UUO rats. Moreover, there was more angiogenesis and endothelial-mesenchymal transition (End-MT) in the UUO group, and these effects were inhibited by eplerenone. Conclusions: The results indicated that this cardiac fibrosis was associated with angiogenesis and that End-MT was related to aldosterone and mineralocorticoid receptor (MR) activation. Moreover, in association with the MR/IL-1ß/VEGFA signaling pathway, early treatment with the MR antagonist eplerenone in rats with UUO-induced CKD may significantly attenuate MR activation and cardiac fibrosis.

Eplerenone ameliorates lung fibrosis in unilateral ureteral obstruction rats by inhibiting lymphangiogenesis.

Chronic kidney disease (CKD) involves progressive and irreversible loss of renal function, often causing complications and comorbidities and impairing the function of various organs. In particular, lung injury is observed not only in advanced CKD but also in early-stage CKD. The present study investigated the potential involvement of mineralocorticoid receptors (MRs) and lymphatic vessels in lung injury using a 180-day unilateral ureteral obstruction (UUO) model for CKD. Changes in lung associated with lymphangiogenesis and inflammatory were analyzed in UUO rats. The pathology of the lung tissue was observed by hematoxylin and eosin and Masson's staining. Detection of the expression of lymphatic vessel endothelial hyaluronic acid receptor-1 (LYVE-1), Podoplanin, vascular endothelial growth factor receptor-3 (VEGFR-3) and VEGF C to investigate lymphangiogenesis. The mRNA and protein expression levels of IL-1ß, monocyte chemotactic protein 1, tumor necrosis factor-α, nuclear factor κB, phosphorylated serum and glucocorticoid-induced protein kinase-1 and MR were evaluated using western blot, reverse transcription-quantitative PCR, immunohistochemical staining and immunofluorescence staining. In the present study, long-term UUO caused kidney damage, which also led to lung inflammation, accompanied by lymphangiogenesis. However, treatment with eplerenone, an MR blocker, significantly reduced the severity of lung injury and lymphangiogenesis. Therefore, lymphangiogenesis contributed to lung fibrosis in UUO rats due to activation of MRs. In addition, transdifferentiation of lymphatic epithelial cells into myofibroblasts may also be involved in lung fibrosis. Collectively, these findings provided a potential mechanism for lung fibrosis in CKD and suggested that the use of eplerenone decreased kidney damage and lung fibrosis.

Esaxerenone inhibits the macrophage-to-myofibroblast transition through mineralocorticoid receptor/TGF-ß1 pathway in mice induced with aldosterone.

Renal fibrosis is the inevitable pathway of the progression of chronic kidney disease to end-stage renal disease, which manifests as progressive glomerulosclerosis and renal interstitial fibrosis. In a previous study, we observed severe interstitial fibrosis in the contralateral kidneys of 6-month unilateral ureteral obstruction (UUO) rats, which was accompanied by increased macrophage infiltration and phenotypic transformation; after eplerenone administration, these effects were reduced. Therefore, we hypothesized that this effect was closely related to mineralocorticoid receptor (MR) activation induced by the increased aldosterone (ALD) level. In this study, we used uninephrectomy plus continuous aldosterone infusion in mice to observe whether aldosterone induced macrophage-to-myofibroblast transition (MMT) and renal fibrosis and investigated the signaling pathways. Notably, aldosterone induced predominantly M1 macrophage-to-myofibroblast transition by activating MR and upregulating TGF-ß1 expression, which promoted renal fibrosis. These effects were antagonized by the MR blocker esaxerenone. These findings suggest that targeting the MR/TGF-ß1 pathway may be an effective therapeutic strategy for renal fibrosis.

Eplerenone inhibits UUO-induced lymphangiogenesis and cardiac fibrosis by attenuating inflammatory injury.

Cardiorenal syndrome (CRS) is the leading cause of death associated with chronic kidney disease (CKD) and end-stage renal disease (ESRD). However, the underlying mechanisms of CRS are still poorly understood. Here, we studied a CKD model of unilateral ureteral obstruction (UUO) and observed pathological cardiac fibrosis and lymphangiogenesis in 180-day old UUO rats, in which inflammatory injury plays a major role. In addition, treatment of UUO rats with eplerenone, a mineralocorticoid receptor blocker (MRB), significantly reduced cardiac lymphangiogenesis and fibrosis. In conclusion, our experimental results showed that cardiac lymphangiogenesis in long-term UUO rats may be involved in the formation of cardiac fibrosis and that eplerenone can alleviate lymphangiogenesis and cardiac fibrosis by inhibiting inflammation.

Chronic intermittent hypoxia induces renal fibrosis through MR activation.

Obstructive sleep apnea syndrome (OSAS) is a disorder characterized by recurrent arousal from sleep and chronic intermittent hypoxia (CIH). OSAS-associated chronic kidney disease is mainly caused by CIH-induced tissue damage. Therefore, an OSAS model was established by CIH exposure in a hypoxic chamber for five weeks. In our study, macrophage infiltration and macrophage-myofibroblast transition (MMT) were observed in the kidneys of CIH rats and appeared to contribute to the development of renal fibrosis. However, the underlying mechanisms are not well defined. We also found that upon binding to the mineralocorticoid receptor (MR), aldosterone stimulated MMT and consequently led to renal fibrosis under hypoxic conditions. Additionally, an in vitro study of RAW264.7 macrophages demonstrated that MR activation may contribute to MMT, which resulted in a predominant M1 phenotype under hypoxic conditions. These effects were reversed by the MR blocker eplerenone. These results provide preliminary evidence that MR activation might be involved in the transdifferentiation of macrophages into myofibroblasts in the CIH model. The attenuation of renal injury demonstrates a protective role of MR blockade in CIH-induced renal disease.

Aldosterone Induces the Proliferation of Renal Tubular Epithelial Cells In Vivo but Not In Vitro.

OBJECTIVE: To investigate the proliferation effect of aldosterone on renal tubular epithelial cells in vivo and in vitro. METHODS: Thirty-two male C57BL/6J mice (20-22 g) were divided randomly into four groups: sham, unilateral nephrectomy (UN), unilateral nephrectomy plus aldosterone infusion (UA), and UA plus eplerenone (UAE). The kidneys were removed 6 weeks after treatment. Expression of proliferating cell nuclear antigen (PCNA) was detected by immunohistochemistry and western blotting. Human kidney proximal tubular epithelial (HK2) and mouse distal convoluted tubule (mDCT) cell lines were stimulated by aldosterone (0, 10-9, 10-8, 10-7, and 10-6 mol/L) in vitro. Cells were collected after 3, 6, 12, 24, 36, and 48 h, and proliferation of each group detected by western blotting, flow cytometry, live imaging, and the MTT assay. In addition, mDCT cells were costimulated with a medium containing a final concentration of 161 mmol/L Na+ and different concentrations of aldosterone, and the number of cells and cellular DNA content was measured by the MTT assay and flow cytometry. RESULTS: Aldosterone could induce a significant increase in the number of PCNA-positive cells in mouse kidneys accompanied by increased deposition of collagen fibers. Eplerenone could inhibit aldosterone-induced cell proliferation and collagen deposition. HK2 cells and mDCT cells administered different concentrations, and different times of aldosterone stimulation failed to cause cell proliferation, and costimulation of aldosterone and salt did not cause proliferation changes in mDCT cells. CONCLUSIONS: Aldosterone perfusion can induce proliferation of mouse kidney cells in vivo, and eplerenone can inhibit this change, but aldosterone stimulates HK2 cells and mDCT in vitro without causing their proliferation.

Huoxue Jiedu Huayu Formula Alleviates Cell Pyroptosis in Contralateral Kidneys of 6-Month-Old UUO Rats through the NLRP3/Caspase-1/IL-1ß Pathway.

OBJECTIVES: To study the protective effects and mechanisms of Huoxue Jiedu Huayu formula on cell pyroptosis through the NLRP3/caspase-1/IL-1ß pathway in contralateral kidneys in 6-month-old unilateral ureteral obstruction (UUO) rats. METHODS: Wistar rats were randomly assigned to 5 groups: a Sham group, a unilateral nephrectomy group (UNX group), a UUO group, a UUO treated with spironolactone group (Spi group), and a UUO treated with Huoxue Jiedu Huayu formula group (HJHF group). After 6 months of oral drug intervention, blood and contralateral kidneys were collected for research. RESULTS: The morphology and function of the contralateral kidneys were essentially normal after unilateral nephrectomy. HJHF obviously decreased serum creatinine, urea, and inflammatory lesions and depressed cell pyroptosis based on the NLRP3/caspase-1/IL-1ß pathway. Moreover, spironolactone, a mineralocorticoid receptor (MR) blocker, suppressed cell pyroptosis through SGK-1 and NF-кB. CONCLUSION: HJHF and spirolactone inhibited excessive activation of MR and then reduced cell pyroptosis, which was dependent on the NLRP3/caspase-1/IL-1ß pathway, to protect the contralateral kidneys of 6-month-old UUO rats.

Astragaloside IV Inhibits Mitochondrial-Dependent Apoptosis of the Dorsal Root Ganglion in Diabetic Peripheral Neuropathy Rats Through Modulation of the SIRT1/p53 Signaling Pathway.

PURPOSE: To investigate the effect of astragaloside IV (AS-IV) on mitochondrial-dependent apoptosis in the dorsal root ganglion of diabetic peripheral neuropathy (DPN) rats through the SIRT1/p53 pathway. METHODS: Diabetic rat model was induced by high-carbohydrate/high-fat diet and intraperitoneal injection of STZ. Diabetic rats were divided into three groups (n =16 per group): DPN group, AS-IV group (60mg/kg/d) and α-lipoic acid (ALA) group (60mg/kg/d). Weight and blood glucose levels were monitored every 4 weeks for 12 weeks. DPN was evaluated using the Von Frey Filaments Test and nerve conduction velocity. The dorsal root ganglia of rats were isolated and the pathological changes of mitochondria were observed by electron microscopy. The activity of mitochondrial electron transport chain complex, mitochondrial membrane potential, malonaldehyde (MDA) and glutathione (GSH) levels were measured. Neural apoptosis was detected using the Terminal Deoxynucleotidyl Nick-End Labeling (TUNEL) assay kit. The cleaved caspase-3, major proteins in the SIRT1/p53 pathway, including SIRT1, acetyl p53, Drp1, BAX, and BCL-2, were detected using immunohistochemistry and Western blot. Gene expression of major proteins in the SIRT1/p53 pathway was also detected. RESULTS: After 12 weeks of treatment, AS-IV and ALA did not significantly affect body weight or fasting glucose levels, but reduced mechanical abnormal pain in DPN and improved nerve conduction velocity. AS-IV and ALA increased the level of GSH and decreased the level of MDA. Both AS-IV and ALA can reduce mitochondrial damage, improve mitochondrial electron transport chain complex activity and mitochondrial membrane potential, and reduce the percentages of positive cells with DNA fragmentation and the expression of cleaved caspase-3 protein. AS-IV and ALA up-regulated the expression of SIRT1 and down-regulated the expression of acetyl-p53, Drp1 and the ratio of BAX to BCL-2. Changes in gene expression were similar. CONCLUSION: AS-IV can reduce the occurrence of mitochondrial-dependent apoptosis by regulating the SIRT1/p53 pathway. It has a similar therapeutic effect as ALA and is therefore a promising drug for the potential treatment of DPN.

Eplerenone Attenuates Fibrosis in the Contralateral Kidney of UUO Rats by Preventing Macrophage-to-Myofibroblast Transition.

Severe renal fibrosis often occurs in obstructive kidney disease, not only in the obstructed kidney but also in the contralateral kidney, causing renal dysfunction. Although the mechanisms of injury in obstructed kidney have been studied for years, the pathogenesis of fibrosis in the contralateral kidney remains largely unknown. Here, we examined long-term unilateral ureteral obstruction (UUO) model in male Sprague-Dawley rats and found that macrophage-to-myofibroblast transition (MMT) is contributing to renal fibrosis in the contralateral kidney of UUO rats. Interestingly, this process was attenuated by treatment of eplerenone, a specific blocker of the mineralocorticoid receptor (MR). In-vitro, stimulating MR in primary cultured or cell line macrophages enhances MMT, which were also inhibited by MR blockade. Collectively, these findings provide a plausible mechanism for UUO-induced injury in the contralateral kidney, suggesting the benefit of using MR blockage as a part of treatment to UUO to protect the contralateral kidney thereby preserve renal function.

UUO induces lung fibrosis with macrophage-myofibroblast transition in rats.

Progression of chronic kidney disease (CKD) to uremia is often accompanied by varying degrees of lung damage and this is also an important cause of death. Although there are many studies on the mechanism of lung injury, it is not clearly understood. Inflammatory macrophages may associated with fibrosis in the lungs. Here, we investigated the role of macrophage-myofibroblast transition (MMT) in lung fibrosis with unilateral ureteral obstruction (UUO) rats. We found that cells undergoing MMT accounted for an important part of the myofibroblast population, and correlated with lung fibrosis, MMT cells in lungs have a predominant M2 phenotype, and this process was attenuated after treatment with eplerenone. In conclusion, our studies provide a possible mechanism for UUO-induced kidney damage and lung injury, indicating the possibility of using eplerenone, a mineralocorticoid receptor blocker, to treat UUO to reduce kidney damage and protect lung function.

Huoxue Jiedu Huayu Recipe Ameliorates Mesangial Cell Pyroptosis in Contralateral Kidney of UUO Rats.

OBJECTIVES: To observe the effects of the Huoxue Jiedu Huayu Recipe (HJHR) on pyroptosis of glomerular mesangial cells in the contralateral unobstructed kidney (CK) of unilateral ureteral obstruction (UUO) rats. METHODS: Sprague-Dawley rats were randomly divided into 4 groups: sham group, UUO group (10 days of left ureter ligation), UUO treated with eplerenone (EPL) (UUO + EPL) group, and UUO treated with HJHR (UUO + HJHR) group. The CKs of all rats were collected for studies. RESULTS: Cell pyroptosis and macrophage infiltration was found in contralateral glomeruli, and nucleotide-binding oligomerization domain-like pyrin domain containing protein 3 (NLRP3) and interleukin (IL)-1ß expression was upregulated in the CK of UUO rats. All of these changes were inhibited by HJHR and eplerenone. To determine how aldosterone (Aldo) activated the mineralocorticoid receptor (MR) and then induced mesangial cell pyroptosis with NLRP3-caspase-1-IL-1ß pathway, human mesangial cells (HMCs) were treated with HJHR and eplerenone, which were examined to detect the expression of NLRP3 inflammasome-associated proteins following treatment with Aldo. CONCLUSION: These results suggest that HJHR and eplerenone suppressed HMC pyroptosis via the MR/NLRP3 pathway.

Eplerenone Ameliorates Cell Pyroptosis in Contralateral Kidneys of Rats with Unilateral Ureteral Obstruction.

BACKGROUND: The progression of chronic renal failure in patients with unilateral renal injury is associated with loss of function in the contralateral kidney, but the molecular mechanism remains unclear. The activation of mineralocorticoid receptor (MR) in the kidney contributes to renal cell damage, leading to apoptosis, pyroptosis, and necrosis. Pyroptosis is a programmed cell death induced by caspase-1, which is usually activated by nod-like receptor pyrin-containing 3 (NLRP3) inflammasomes. Our study aimed to investigate the effects of eplerenone (EPL) on cell pyroptosis in the contralateral kidneys of unilateral ureteral obstruction (UUO) rats. METHODS: Sprague-Dawley rats were randomly divided into 3 groups: sham group, UUO group (10 days of left ureter ligation), and UUO treated with EPL (UUO + EPL) group. The contralateral kidneys of all rats were collected for studies. RESULTS: We observed evidently increased number of pyroptosis cells in the contralateral kidneys of UUO rats compared to those from Sham rats. The expression of NLRP3, caspase-1, interleukin-1ß, serum and glucocorticoid-inducible protein kinase-1, and nuclear factor kappa B were also upregulated in the contralateral kidneys of UUO rats compared to Sham kidneys, and these effects were reduced by MR blocker EPL. CONCLUSION: Our data suggest that the activation of MR is involved in NLRP3/caspase-1 pathway-induced cell pyroptosis in the contralateral kidney of UUO model.

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.

[Effect of Huayu Jiedu Recipe on the Expressions of NLRP3, Caspasel, and IL-1 ß in Kidneys of Obstructive Nephropathy Rats].

Objective To observe the effect of Huayu Jiedu Recipe (HJR) on the expressions of nucleotide-binding oligomerization domain (NOD)-like receptor protein 3 (NLRP3) , Caspase-1 , IL-1 ß in kidneys of obstructive nephropathy rats. Methods Totally 40 clean grade SD rats were randomly divided into the sham-operation group (n =10) and the model group (n =30). The model of obstructive nephropa- thy was established by unilateral ureteral obstruction (UUO). Totally 30 successfully modeled UUO rats were randomly divided into the model group, the Western medicine group, the Chinese medicine group, 10 in each group. Eplerenone (100 mg . kg ⁻¹ . d⁻¹) was administrated to rats in the Western medicine group. HJR (13.7 g . kg ⁻¹ . d⁻¹) was administrated to rats in the Chinese medicine group. Equal volume of normal saline was administered to rats in the sham-operation group and the model group. All medica- tion was performed once daily for 10 successive days. The serum IL-1 ß level was detected. Protein and mRNA expressions of NLRP3, Caspase-1, and IL-1 ß in renal tissue were detected. TUNEL positive rate was detected by TUNEL method. Results The expression of NLRP3 was not obviously seen, Caspase-1 and IL-1 ß were weakly expressed, and only fewer amount of TUNEL positive cells could be seen in the sham-operation group. Compared with the sham-operation group, serum IL-1ß level increased (P < 0. 01) , mRNA and protein expression of NLRP3, Caspase-1 , and IL-1 ß were up-regulated in renal tissue of the model group (P <0. 01). NLRP3 was mainly expressed in renal interstitial macrophages and renal tubular epithelial cells. Caspase-1 and IL-1 ß were mainly expressed in the cytoplasm of renal tubular epithelial cells. TUNEL positive cells were significantly increased, mainly dominated in interstitial expanded epithelial cells of distal tubules (P <0. 01). Compared with the model group, serum IL-1 ß level was significantly decreased (P <0. 01) ; mRNA and protein expressions of NLRP3, Caspase-1 , and IL- ß were obviously down-regulated (P <0. 01) , and the TUNEL positive rate was obviously decreased (P <0. 05, P < 0. 01) in the two medicated groups. Conclusion HJR could down-regulate mRNA and protein expres- sions of NLRP3, Caspase-1 , and IL-1ß, thus attenuating inflammatory injury of renal tissue.