Renal Tissues Of Diabetic Rats Research Articles

Alpha-cyperone mitigates renal ischemic injury via modulation of HDAC-2 expression in diabetes: Insights from molecular dynamics simulations and experimental evaluation

Chronic diabetes mellitus is reported to be associated with acute kidney injury. The enzyme histone deacetylase-2 (HDAC-2) was found to be upregulated in diabetes-related kidney damage. Alpha-cyperone (α-CYP) is one of the active ingredients of Cyperus rotundus that possesses antioxidant and anti-inflammatory effects. We evaluated the effect of α-CYP on improving oxidative stress and tissue inflammation following renal ischemia/reperfusion (I/R) injury in diabetic rats. The effect of α-CYP on HDAC-2 expression in renal homogenates and in the NRK-52 E cell line was evaluated following renal I/R injury and high glucose conditions, respectively. Molecular docking was used to investigate the binding of α-CYP with the HDAC-2 active site. Both renal function and oxidative stress were shown to be impaired in diabetic rats due to renal I/R injury. Significant improvements in kidney/body weight ratio, creatinine clearance, serum creatinine, blood urea nitrogen (BUN), and uric acid were observed in diabetic rats treated with α-CYP (50 mg/kg) two weeks prior to renal I/R injury. α-CYP treatment also improved histological alterations in renal tissue and lowered levels of malondialdehyde, myeloperoxidase, and hydroxyproline. Treatment with α-CYP suppressed the increased HDAC-2 expression in the renal tissue of diabetic rats and in the NRK-52 E cell line. The molecular docking reveals that α-CYP binds to HDAC-2 with good affinity, ascertained by molecular dynamics simulations and binding free energy analysis. Overall, our data suggest that α-CYP can effectively prevent renal injury in diabetic rats by regulating oxidative stress, tissue inflammation, fibrosis and inhibiting HDAC-2 activity.

Luteolin attenuates diabetic nephropathy via inhibition of metalloenzymes in rats

Objective: To investigate the renoprotective effects of luteolin on diabetes in rats. Methods: One week after administration of streptozotocin 55 mg/kg intraperitoneally, rats were given 25, 50, and 75 mg/kg/day of luteolin orally for another eight weeks. At the end of the experiment, body weight, blood glucose level, biochemical parameters for renal function (serum creatinine, blood urea nitrogen, uric acid, serum albumin, and total protein), kidney histology, matrix metalloproteinase (MMP)-2, MMP-9, and histone deacetylase 2 (HDAC-2) expression, and malondialdehyde, myeloperoxidase, and hydroxyproline content in renal tissue were evaluated. High glucose- induced damage using NRK-52E cell line was studied to evaluate cell viability and metalloenzyme expression. Additionally, in silico studies including docking and molecular dynamics simulations were conducted. Results: MMP-2, MMP-9, and HDAC-2 expressions were significantly increased in high glucose-induced NRK-52E cells and the renal tissue of diabetic rats. However, these changes were reversed by luteolin at the administered doses. Additionally, luteolin significantly reduced oxidative stress, inflammation, and fibrosis, as well as improved biochemical parameters in diabetic rats. Furthermore, luteolin at the examined doses markedly alleviated diabetes-induced histopathological changes in renal tissues. Conclusions: Luteolin effectively attenuates streptozotocin- induced diabetic nephropathy in rats by inhibiting MMP-2, MMP- 9, and HDAC-2 expression, and reducing oxidative stress and inflammation.

Bacoside-A Improves Antioxidant Enzymes and Alleviates Oxidative Stress Coexist with Markers of Renal Function in a Rat Model of Type 2 Diabetes Mellitus.

Oxidative stress, imbalanced antioxidants, and dysregulated renal lipids are closely linked with diabetic nephropathy and eventual cause of end-stage renal failure. This study was performed to investigate the protective effect of bacoside-A on markers of lipid peroxidation, renal lipids, and markers of renal function in diabetic rats. Experimental diabetes was induced in Wistar rats by a single dose of streptozotocin [40 mg/kg body weight (BW)] via intraperitoneal injection. Oral administration of bacoside-A (10 mg/kg BW) and glibenclamide, a reference drug, continued for 45 days. Diabetic rats showed a significant increase in the levels of plasma glucose, renal lipids, markers of renal lipid peroxidation, and plasma biomarkers of renal function such as urea, uric acid, and creatinine. A significant decrease in the levels of plasma insulin, nonenzymatic antioxidants, and the activity of enzymatic antioxidants was seen compared with the normal controls. Bacoside-A (10 mg/kg BW) and glibenclamide (600 μg/kg BW) administered to diabetic rats resulted in a significant decrease in plasma glucose and renal lipids but a significant increase in the plasma insulin level. In addition, bacoside-A achieved a remarkable increase in the activity of enzymatic antioxidants and the levels of nonenzymatic antioxidants in the renal tissue of diabetic rats, along with significant decreases in the markers of lipid peroxidation and those of renal function, consequently substantiating the protecting effectiveness of bacoside-A in a diabetic state. These biochemical observations were supported by a histopathological study of the renal tissue. The present study suggested that bacoside-A, a triterpenoid, offers a higher renoprotective effect to counter abnormal parameters of renal function in diabetes-induced renal injury.

Biochanin-A Protects Rats from Diabetes-associated Cardiorenal Damage by Attenuating Oxidative Stress through Activation of Nrf-2/HO-1 Pathway

The current study is designed to evaluate the cardiorenal protective efficacy of the Biochanin-A (BCA) against high-fat-diet (HFD) and streptozotocin (STZ)-induced diabetes in rats. BCA (10mg/kg body weight) was administered to the diabetic rats for a period of 30 days and evaluated its effect on hyperglycemic markers, formation of lipid peroxidation, nitric oxide production and antioxidant enzymes such as superoxide dismutase, catalase and glutathione mediated enzymes. Further, we assessed the impact of BCA on nuclear factor erythroid 2-related factor-2 (Nrf-2) and heme oxygenase-1 (HO-1) along with antioxidant enzymes mRNA expressions by RT-PCR. BCA administration to diabetic rats resulted in attenuation of hyperglycemia and oxidative stress in both the kidney and heart. Further, BCA enhanced the endogenous antioxidant activities in the kidney and heart and up-regulated their corresponding mRNA expressions. In addition, BCA treatment produced notable up-regulation of Nrf-2 and HO-1 mRNA expressions in the cardiac and renal tissue of diabetic rats. In conclusion, the current study revealed that BCA could protect from diabetes-induced complications such as cardiomyopathy and nephropathy by activating the Nrf-2/HO-1 pathway and enhancing the endogenous antioxidant state in the kidney and heart.

Ameliorative effect of extracts from scent (Ocimum basilicum), mentha (Mentha piperita), and thyme (Thymus vulgaris) leafy spices on glycemic, purinergic molecules, and oxidative status in renal tissue of diabetic rats

Ameliorative effect of extracts from scent (Ocimum basilicum), mentha (Mentha piperita), and thyme (Thymus vulgaris) leafy spices on glycemic, purinergic molecules, and oxidative status in renal tissue of diabetic rats

Renoprotective potential of myo-inositol on diabetic kidney disease: Focus on therole of the PINK1/Parkin pathway and mitophagy receptors.

Recent studies have emphasized the role of mitochondria in renal function as well as in renal injury. Poor mitochondrial quality control mechanisms including mitochondrial fusion, fission and mitophagy are major contributors for progression of diabetic renal injury. The current study is aimed to evaluate the protective role of myo-inositol (MI) against diabetic nephropathy (DN) by utilizing high glucose exposed NRK 52E cell and streptozotocin (STZ) induced DN model. MI supplementation (at doses 37.5and 75 mg/kg) ameliorated albuminuria and enhanced the renal function as indicated significant improvement in urinary creatinine and urea levels. On the other hand, the western blot analysis of both in vitro and in vivo studies has revealed poor mitophagy in renal cells which was reversed upon myo-inositol treatment. Apart from targeting the canonical PINK1/Parkin pathway, we also focused on the role mitophagy receptors prohibitin (PHB) and NIP3-like protein (NIX). A significant reduction in expression of NIX and PHB2 was observed in renal tissue of diabetic control rats and high glucose exposed NRK 52E cells. Myo-inositol treatment resulted in positive modulation of PINK1/Parkin pathway as well as PHB2 and NIX. Myo-inositol also enhanced the mitochondrial biogenesis in renal tissue of diabetic rat by upregulating Nrf2/SIRT1/PGC-1α axis. The current study thus underlines the renoprotective effect myo-inositol, upregulation of mitophagy proteins and mitochondrial biogenesis upon myo-inositol treatment.

Therapeutic role of Azadirachta indica leaves ethanolic extract against diabetic nephropathy in rats neonatally induced by streptozotocin

ABSTRACT Diabetic nephropathy (DN) is manifested by chronic loss of renal function due to damage of glomeruli and renal tubules. Therefore, this study is mainly designed to evaluate the therapeutic role of Azadiracta indica (neem) leaves extract as a novel approach for treatment of DN in rats neonatally induced by streptozotocin (STZ). For this study, 40 offspring were selected after parturition and categorized into four groups (n = 10). Group1: control group, group 2: neem leaves extract supplemented group, group 3: diabetic group that injected with a single dose of STZ and group 4: diabetic group treated with neem extract. The results revealed deleterious histological and ultrstructural changes in the renal tissues of diabetic rats. Such changes included atrophied glomeruli, dilated renal cortical tubules and scattered hemorrhage spots, thickening of glomerular basement membrane, expansion of mesangial matrix and pyknotic podocyte. Additionally, the proximal convoluted tubule and distal tubule showed cytoplasmic vacuolation, vacuolated mitochondria, scattered lipid droplets, lost microvilli and disrupted basal lamina and basal infoldings. Moreover, significant decreased levels of serum antioxidants (SOD&CAT) and significant increased levels of serum MDA, urea and creatinine were noticed in diabetic rats. Neem leaves extract successfully alleviated the histological and ultrastructural as well as biochemical changes induced by diabetes.

Oxymatrine improves renal fibrosis and inflammation in diabetic rats by modulating CHK1/2 phosphorylation

To explore the role of cell cycle checkpoint kinase 1/2 (CHK1/2) in mediating the inhibitory effect of oxymatrine (OMT) against renal inflammation and fibrosis in diabetic rats. SD rats were randomly divided into normal control group, diabetes model group (DM) and OMT treatment group (n=6). HE and Masson staining were used to observe histopathological changes of the renal tissue, and the expressions of CHK1, CHK2, p-CHK1 and p-CHK2 were localized by immunohistochemical staining. The contents of interleukin-6 (IL-6) and IL-1β in the renal tissue were detected using ELISA, and the expression levels of CHK1, CHK2, p-CHK1, p-CHK2, type Ⅲ collagen (Col-Ⅲ), type Ⅳ collagen (Col-Ⅳ), and fibronectin (FN) were determined using Western blotting. The changes in the expressions of CHK1, CHK2, p-CHK1, p-CHK2, Col-Ⅲ, Col-Ⅳ and FN proteins were also examined with Western blotting in NRK-52E cells in response to high glucose exposure, OMT treatment and siRNA-mediated CHK1/2 knockdown. In diabetic rats, OMT treatment significantly decreased the levels of blood glucose, serum creatinine and 24 h urinary protein (P < 0.05) and obviously improved inflammatory cell infiltration and fibrosis phenotype in the renal tissue (P < 0.05). CHK1 and CHK2 were mainly expressed in the cytoplasm and nuclei of renal tubule cells, and their phosphorylation levels were significantly higher in DM group than in the control group and OMT group. OMT treatment significantly decreased the protein expression levels of p-CHK1, p-CHK2, Col-Ⅲ, Col-Ⅳ and FN in the renal tissue of diabetic rats and in NRK-52E cells exposed to high glucose (P < 0.05). In NRK-52E cells, CHK1/2 knockdown resulted in significant reduction of the protein expressions of p-CHK1/2, Col-Ⅲ, Col-Ⅳ and FN (P < 0.05). The inhibitory effects of OMT against renal inflammation and fibrosis in diabetic rats are mediated probably by lowered phosphorylation levels of CHK1 and CHK2, which result in reduced release of the downstream inflammatory mediators and decreased secretion and deposition of extracellular matrix.

Study of long non-coding RNA and mitochondrial dysfunction in diabetic rats

Abstract Diabetes mellitus (DM) is a worldwide health problem. Many factors participate in the pathogenesis of DM, including genetic, autoimmune, metabolic, dietary and environmental factors. Intact mitochondrial function is essential for prompt cellular metabolism and energy balance. Malfunctioning mitochondria lead to disturbed glucose metabolism and therefore evolving of DM. Epigenetics plays a role in the control of geneencoded proteins of mitochondrial function and dynamics. One of the primary epigenetic effectors is a family of long non-coding RNAs. The role of lncRNA, H19 in the regulation of mitochondrial dynamics has been recently investigated. The Aim of the work This study aims to evaluate the possible functional role of lncRNA, H19 and its relation to mitofusin-2 (MFN2) expression in diabetic rats. Subjects and methods This study was performed on adult male albino rats divided into diabetic and control groups. Induction of type 1 DM was conducted through single intraperitoneal injection of streptozotocin. Serum measurement of glucose, lipid profile, urea, creatinine, and creatine kinase were performed. Blood pressure measurement, ECG recording, and echocardiography were also performed. Histological examination of cardiac and renal tissues was also performed. In addition, quantitative expression of cardiac and renal tissue MFN2 and lncRNA H19 was determined using qPCR. Results Serum CK-MB and lipid profile levels were markedly elevated in diabetic group compared to controls. Also, kidney functions (serum creatinine, creatinine clearance and albumin creatinine ratio) were markedly elevated in diabetic group compared to controls. Histological examination revealed necrotic changes and intercellular micro hemorrhages in both cardiac and renal tissues of diabetic rats. Expression level of MFN2 gene was lower in diabetic heart and significantly lower in diabetic kidney, as compared to control. Expression of lncRNA H19 was higher in diabetic heart and diabetic kidney as compared to control but without statistical significance. Conclusion In diabetic rats, hyperglycemia had inverse relationship with mitofusin expression and direct proportional relationship with H19 expression. We concluded that hyperglycemia has effect on mitochondrial dynamics suppressing fusion in favor of fission and mitophagy, while H19 expression serve to counterpart the effect of hyperglycemia. In the future, MFN and H19 could serve as potential therapeutic target to reverse effects of hyperglycemia and its complications in DM.

Stabilized-chitosan selenium nanoparticles efficiently reduce renal tissue injury and regulate the expression pattern of aldose reductase in the diabetic-nephropathy rat model

One of the global alarming prevalent metabolic diseases is Type 2 diabetes mellitus (T2DM) than other diabetes and sustains a substantial burden on public and healthcare systems. This study attempts to endeavor the beneficial effect of chitosan stabilized nanoparticles Ch-SeNPs on combating diabetic nephropathy (DN) after induction of T2DM in rats (DN.STZ-induced T2D). High-fat diet (HFD) and STZ were used for the induction of T2DM in rats, and then they were treated with either metformin alone (MEF) (500 mg/kg b.wt.) or combined with (Ch-SeNPs) (2 mg Se/kg b.wt.) for eight weeks. The microvascular complications in renal tissue of diabetic rats were pronounced by the prevalence of microalbuminuria and elevated levels of urea, creatinine, and BUN. Pronounced oxidative stress with enhanced inflammatory response. In the urine of diabetic rats, a marked increase in Kim 1, β2-microglobulin, and urinary albumin. Renal morphological alterations were observed in all groups upon induction of T2DM, except for the Ch-SeNPs/MEF group showed noticeable improvements. The expression levels of Aldo-keto reductase AKr1B1, profibrotic protein transforming growth factor-β1 (TGF-β1), nestin, desmin, and vimentin, were up-regulated in the diabetic group. Significant down-regulation of their expression and restored antioxidant capacity was observed in the combined-treated group than single treated ones. Ch-SeNPs helped limit the prevalence of TNF-α, IL-6, and IL-1β while used after T2DM induction by STZ and HFD. Ch-SeNPs/MEF co-therapy could effectively guard the kidneys and reduce the renal tissue injury via inhibiting oxidative stress and restoring glucose hemostasis, which indicates a promising line for treating T2DM nephropathy.

LncRNA MALAT1 Promotes Renal Fibrosis in Diabetic Nephropathy by Targeting the miR-2355-3p/IL6ST Axis.

Long noncoding RNA (lncRNAs) metastasis–associated lung adenocarcinoma transcript 1 (MALAT1) has been reported in diabetic nephropathy (DN) about its effect on podocyte function and cell heat shock induced by hyperglycemia. However, the biological mechanism of MALAT1 regulating DN fibrosis needs further study. In this study, SD rats were administrated with streptozotocin (STZ) to establish a diabetes model. In vitro, human renal tubular epithelial cells (HK-2 and 293T) were treated with high glucose (HG). Here, we found that MALAT1 was upregulated in renal tissues of diabetic rats and HG-treated cells, and HG treatment promoted cell proliferation and invasion. MALAT1 overexpression aggravated protein levels of collagen I (col I), collagen IV (col IV), fibronectin (FN), and laminin (LN) in HK-2 cells, while MALAT1 knockdown exerted the opposite effect. Moreover, the luciferase reporter gene and pull-down assays demonstrated that MALAT1 interacted with miR-2355-3p. The miR-2355-3p level was downregulated in diabetic rats and HG-treated cells, and MALAT1 overexpression inhibited the miR-2355-3p level. Bioinformatics prediction and luciferase reporter gene assay revealed that interleukin 6 signal transducer (IL6ST) was a target of miR-2355-3p. In addition, miR-2355-3p overexpression attenuated fibrosis-related gene levels in HG-treated cells by inhibiting IL6ST expression and inactivating the recombinant signal transducer and activator of the transcription 3 (STAT3) signaling pathway. Knockdown of miR-2355-3p reversed the inhibitory effect of MALAT1 knockdown on IL6ST, col I, col IV, FN, and LN protein levels in HG-induced cells. Overexpression of MALAT1 aggravated cell damage in HG-induced cells via the miR-2355-3p/IL6ST/STAT3 signaling pathway. Finally, enhanced renal fibrosis and kidney tissue damage were observed in diabetic rats. In conclusion, MALAT1 overexpression may enhance renal fibrosis in diabetic rats and cell damage in HG-induced HK-2 cells via the miR-2355-3p/IL6ST axis, which provides a new perspective of DN treatment.

APIGENIN ATTENUATES DIABETIC NEPHROPATHY IN TYPE 1 DIABETIC RATS

Objective: The present study was designed to evaluate the effect of apigenin on progression and development of diabetic nephropathy in diabetic rats. Design and method: Adult male albino Wistar rats were divided into 7 groups: control, diabetic control, apigenin treatment groups (5–20 mg/kg; p.o.), ramipril (2 mg/kg; p.o.) and apigenin per se (20 mg/kg) group. Except control and per se groups, type 1 diabetes in other groups were induced by a single injection of streptozotocin (55 mg/kg; i.p). After confirmation of diabetes (FBG&gt;250 mg/dl), rats were randomly divided into different treatment groups and observed for period of 8 months. Results: After 8 months, STZ resulted in attenuation of renal function (increased BUN and serum creatinine), increased oxidative stress and inflammation (increased cytokines and NF-kappa B) in the diabetic rats. In addition, there was fibrosis (increased transforming growth factor, fibronectin and type IV collagen), apoptosis (increased bax, caspase-3 and decreased bcl-2) and activation of MAPK pathway in diabetic-control group. These results were further supported by histopathological examination, which revealed presence of inflammation, collagen deposition and glomerulosclerosis in renal tissue of diabetic rats. In contrast, pre-treatment with apigenin significantly ameliorated STZ-induced functional and pathological changes in diabetic rats. In addition, it attenuated fibrosis, inflammation and apoptosis and also prevented activation of MAPK pathway in diabetic rats. All these protective effects were comparable to the ramipril treated group. Conclusions: Apigenin ameliorated oxidative stress, inflammation, apoptosis and fibrosis in diabetic rats by attenuation of MAPK pathway and prevented diabetic complication in diabetic rats.

Phytochemicals of Periploca aphylla Dcne. ameliorated streptozotocin-induced diabetes in rat

BackgroundPeriploca aphylla is used by local population and indigenous medicine practitioners as stomachic, tonic, antitumor, antiulcer, and for treatment of inflammatory disorders. The aim of this study was to evaluate antidiabetic effect of the extract of P. aphylla and to investigate antioxidant and hypolipidemic activity in streptozotocin (STZ)-induced diabetic rats.MethodsThe present research was conducted to evaluate the antihyperglycemic potential of methanol extract of P. aphylla (PAM) and subfractions n-hexane (PAH), chloroform (PAC), ethyl acetate (PAE), n-butanol (PAB), and aqueous (PAA) in glucose-overloaded hyperglycemic Sprague-Dawley rats. Based on the efficacy, PAB (200 mg/kg and 400 mg/kg) was tested for its antidiabetic activity in STZ-induced diabetic rats. Diabetes was induced via intraperitoneal injection of STZ (55 mg/kg) in rat. Blood glucose values were taken weekly. HPLC-DAD analysis of PAB was carried out for the presence of various polyphenols.ResultsHPLC-DAD analysis of PAB recorded the presence of rutin, catechin, caffeic acid, and myricetin. Oral administration of PAB at doses of 200 and 400 mg/kg for 21 days significantly restored (P < 0.01) body weight (%) and relative liver and relative kidney weight of diabetic rats. Diabetic control rats showed significant elevation (P < 0.01) of AST, ALT, ALP, LDH, total cholesterol, triglycerides, LDL, creatinine, total bilirubin, and BUN while reduced (P < 0.01) level of glucose, total protein, albumin, insulin, and HDL in serum. Count of blood cells and hematological parameters were altered in diabetic rats. Further, glutathione peroxidase, catalase, superoxide dismutase, glutathione reductase, and total soluble protein concentration decreased while concentration of thiobarbituric acid reactive substances and percent DNA damages increased (P < 0.01) in liver and renal tissues of diabetic rats. Histopathological damage scores increased in liver and kidney tissues of diabetic rats. Intake of PAB (400 mg/kg) resulted in significant improvement (P < 0.01) of above parameters, and results were comparable to that of standard drug glibenclamide.ConclusionThe result suggests the antihyperglycemic, antioxidant, and anti-inflammatory activities of PAB treatment in STZ-compelled diabetic rat. PAB might be used as new therapeutic agent in diabetic patients to manage diabetes and decrease the complications.

Tanshinone IIA Ameliorates Streptozotocin-Induced Diabetic Nephropathy, Partly by Attenuating PERK Pathway-Induced Fibrosis

PurposeTanshinone IIA (Tan IIA), a compound extracted from Salvia miltiorrhiza, can improve type II diabetes, while the molecular mechanisms underlying Tan IIA-mediated protective effects in diabetic nephropathy are unclear. This study explored the protective actions of Tan IIA on renal tissues in streptozotocin (STZ)-induced diabetic nephropathy.Materials and MethodsTan IIA (2, 4, 8 mg/kg/day) was daily administered to STZ-treated rats by intraperitoneal injection for 42 days. The morphologic pathology was evaluated by hematoxylin-eosin and Masson’s trichrome staining, and transmission electron microscopy. The protein expression levels in renal tissues were evaluated by Western blotting and immunohistochemistry; the mRNA expression level was determined by quantitative real-time PCR.ResultsTan IIA at 2 and 4 mg/kg attenuated the increase in the levels of uric acid and blood urea nitrogen and restored the reduction in the superoxide dismutase activity in the serum of the diabetic rats. Tan IIA at 2 and 4 mg/kg, but not 8 mg/kg, ameliorated the thickening of renal tubule in the diabetic rats; Tan IIA at 2 and 4 and 8 mg/kg attenuated the thickening of glomerular basement membrane and the collagen deposition in the renal tissues of the diabetic rats. Tan IIA treatment at 2, 4, 8 mg/kg decreased the expression levels of transforming growth factor-beta1, TSP-1, Grp78 and CHOP in the diabetic rats. Tan IIA at 2 and 4 and 8 mg/kg attenuated the increase in the protein levels of p-PERK, p-elf2α and ATF-4 from the renal tissues of diabetic rats, while the protein level of AFT-6 and the mRNA expression levels of XBP-1t, XBP-1s and p58IPK in the renal tissues were not affected by STZ or Tan IIA treatment.ConclusionTan IIA-mediated protective effects on the STZ-induced diabetic nephropathy may be associated with the reduced endoplasmic reticulum stress via attenuating PERK signaling activities.

VASH-1 Regulates Oxidative Stress and Fibrosis in Diabetic Kidney Disease via SIRT1/HIF1α and TGFβ1/Smad3 Signaling Pathways

Aims: To investigate the role of Vasohibin-1 (VASH-1), silence information adjustment factor 2-related enzyme 1 (SIRT1)/hypoxic-inducible factor 1α (HIF1α) and transforming growth factor-β1 (TGFβ1) /Smad3 signaling pathways in oxidative stress and fibrosis of diabetic kidney disease (DKD).Materials and Methods: A diabetic rat model was established in vivo and rat mesangial cells (RMCs) were cultured in vitro with high glucose via transfection with Vash1 small interfering RNA (siRNA), Hif1a siRNA, Sirt1 siRNA and TGFβ1/Smad3 pathway inhibitor (SB431542). Renal histology was used to detect renal changes. Real-time PCR and western blot were used to analyze the expression of VASH-1, SIRT1, HIF1α, TGFβ1, Smad3, vascular endothelial growth factor (VEGF), connective tissue growth factor (CTGF) and fibronectin (FN). Expression levels of tumor necrosis factor-α (TNFα), TGFβ1, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-PX), and malondialdehyde (MDA) in rat tissues and cell culture supernatant were detected by ELISA and chemiluminescence assay, while cell proliferation was detected by CCK-8.Results: The level of VASH-1 in renal tissues of diabetic rats was decreased, while both high glucose and Vash1 siRNA inhibited the expression of VASH-1 and SIRT1, increased the levels of HIF1α, TGFβ1, and Smad3 in RMCs, thus up-regulating oxidative stress and fibrosis factors, and abnormally increasing cell proliferation activity (P < 0.05). However, inhibition of SIRT1/HIF1α signaling pathway only reduced TGFβ1 and Smad3 (P < 0.05), while VASH-1 remained unchanged (P > 0.05).Conclusion: VASH-1 was under-expressed in renal tissues of diabetic rats and regulated the pathological process of oxidative stress and fibrosis in DKD via downstream SIRT1/HIF1α and TGFβ1/Smad3 signaling pathways.

Ginsenoside Rg1 Alleviates Podocyte Injury Induced by Hyperlipidemia via Targeting the mTOR/NF-κB/NLRP3 Axis.

Background Podocyte injury plays an important role in diabetic nephropathy (DN). The aim of this study was to determine the potential therapeutic effects of the ginsenoside Rg1 on hyperlipidemia-stressed podocytes and elucidate the underlying mechanisms. Methods In vitro and in vivo models of DN were established as previously described, and the expression levels of relevant markers were analyzed by Western blotting, real-time Polymerase Chain Reaction (PCR), immunofluorescence, and immunohistochemistry. Results Ginsenoside Rg1 alleviated pyroptosis in podocytes cultured under hyperlipidemic conditions, as well as in the renal tissues of diabetic rats, and downregulated the mammalian target of rapamycin (mTOR)/NF-κB pathway. In addition, Rg1 also inhibited hyperlipidemia-induced NLRP3 inflammasome in the podocytes, which was abrogated by the mTOR activator L-leucine (LEU). The antipyroptotic effects of Rg1 manifested as improved renal function in the DN rats. Conclusion Ginsenoside Rg1 protects podocytes from hyperlipidemia-induced damage by inhibiting pyroptosis through the mTOR/NF-κB/NLRP3 axis, indicating a potential therapeutic function in DN.

PUFAs supplementation affects the renal expression of pannexin 1 and connexins in diabetic kidney of rats.

In diabetic nephropathy (DN), intercellular communication is disrupted. Connexins (Cx) have a crucial role in that process. Dietary ratios and supplementation with polyunsaturated fatty acids (PUFAs) can alleviate diabetic complications and cause alterations in Cx levels. Although pannexins (Panx) share similarities with members of the Cx family, their function in diabetic nephropathy has still not been fully determined. We studied the influence of PUFA supplementation on the immunoexpression of Px1 and Cx family members in diabetic kidneys of rats. Four groups of rats in experimental DM1 model were supplemented with different dietary n-6/n-3 ratios; ≈7 in control (C) and diabetic groups (STZ), ≈ 60 in the STZ + N6 group and ≈ 1 (containing 16% EPA and 19% DHA) in the STZ + N3 group. Immunoexpression of Cx40, Cx43, Cx45 and Panx1 was evaluated in the renal tissue of diabetic rats using immunohistochemistry. Diabetes significantly decreased the protein expression of Cx40 and Cx43 and increased Panx1 protein expression in the renal cortex (p < 0.05-p < 0.01). There was a significant impact of diet on Cx and Panx1 immunoexpression. Dietary supplementation with a high n-6/n-3 ratio downregulated the protein expression of Cx45 and Panx1 in diabetic rats (p < 0.05-p < 0.01), while Cx43 immunoexpression was increased in diabetic rats fed with high and low n-6/n-3 ratios (p < 0.01-p < 0.001). Hyperglycaemic conditions in DN interfere with cell-to-cell communication and disturb the connection between cells and their immediate environment due to variations in connexin and pannexin immunoexpression. These variations can be regulated by PUFA dietary intake, suggesting their beneficial effect and possible therapeutic option.

Reducing Effects of Aerobic Exercise Training Combined with Berberine Chloride Supplementation on the Apoptotic Markers of Kidney in Streptozotocin-Induced Diabetic Male Rats

Objectives: The present study aimed at evaluating the effects of aerobic exercise training (ET) and different doses of berberine chloride (BC) supplementation on apoptotic indices in renal tissue of streptozotocin (STZ)-induced diabetic Wistar rats. Methods: In the current study, 64 Wistar rats were divided into two normal and diabetic groups and then the normal group was divided into two subgroups including normal control (NC) and normal exercise training (NET, 3 d/wk, 50% - 55% of VO2max for six weeks) and the diabetic group was divided into six subgroups including diabetic control (DC), diabetic exercise training (DET), diabetic BC15 (DBC: 15 mg/kg), diabetic BC30 (DBC: 30 mg/kg), diabetic BC15+ET (DBC15+ET), and diabetic BC30+ET (DBC30+ET). Intraperitoneal injection of STZ (100 mM citrate buffer, pH 4.5 contained 60 mg/kg STZ) was used for diabetes induction. Results: There was no significant difference in the levels of caspase-3 and Bax protein between the NC and DC groups (P = 0.59 and P = 0.49, respectively). The diabetic rats treated with BC30+ET demonstrated a reduction in caspase-3 compared with NC, DC, DBC15, and NET groups (P = 0.001, P = 0.02, P = 0.001, and P = 0.04, respectively). The results also revealed no significant difference in Bcl-2 protein level after six weeks of ET and BC supplementation in renal tissue of the studied groups (P = 0.33). Conclusions: These results suggested that aerobic exercise training combined with higher doses of BC could decrease pro-apoptotic indices with an increase in Bcl-2 to Bax ratio and suppress apoptotic cell death in the renal tissue of diabetic rats.

Empagliflozin Attenuates Renal and Urinary Markers of Tubular Epithelial Cell Injury in Streptozotocin-induced Diabetic Rats

Empagliflozin, a SGLT-2 inhibitor, improves diabetic nephropathy through its pleiotropic anti-inflammatory effects. The present study aims to evaluate empagliflozin effects on renal and urinary levels of tubular epithelial cell injury markers in streptozotocin-induced diabetic rats. Empagliflozin at 10mg/kg (p.o.) was administered for 4weeks, beginning 8weeks after induction of diabetes. Renal function as well as markers of renal tubular epithelial cell injury were assessed in kidney tissue homogenates and urine. Empagliflozin was able to ameliorate diabetes induced elevations in serum cystatin C levels. It also alleviated renal KIM-1/NGAL levels and urinary albumin, α-GST, and RBP excretions. In addition to decreasing urinary levels of cell cycle arrest indices i.e. TIMP-2 and IGFBP7, empagliflozin mitigated acetylated NF-κB levels in renal tissues of diabetic rats. As a whole, these findings reveal empagliflozin capability in improving diabetic nephropathy via ameliorating indices of renal inflammation, injury, and cell cycle arrest on streptozotocin-induced diabetic rats.

Lutein attenuates diabetic-induced renal damage via inhibiting oxidative and nitrosative stresses

Diabetic nephropathy is a complex disease that involves production of free radicals, which are strong stimulus for pro-inflammatory factors. Present study was designed to explore the potential alleviating effects of lutein against streptozotocin-induced diabetic renal oxidation, inflammation and apoptosis in rats. Lutein was supplemented with diets content in three different doses (40, 80 and 160 mg/kg diets). Levels of glucose, albumin, creatinine and urea were determined in serum and urine. Renal expression of pro-inflammatory cytokines, nucleic acids and caspase-3 activity were estimated and also the kidney levels of thiobarbituric acid reactive substances (TBARS), total and non-protein sulfhydryl groups (T-SH and NP-SH), nitric oxide (NO) and inducible nitric oxide synthase (iNOS) along with superoxide dismutase (SOD) and catalase (CAT) activities. Renal histopathological features were analyzed. The diabetic animals showed apparent alterations in serum and urine biochemistry and also demonstrated evident elevated renal levels of pro-inflammatory mediators and apoptosis. Measured oxidative/nitrosative stress biomarkers were found altered markedly in the renal tissues of diabetic rats. Lutein supplementation to the diabetic animals significantly improved serum and urinary biochemistry. In renal tissue, the altered pro-inflammatory cytokines, nucleic acids and caspase-3 activity were ameliorated following lutein supplementation. Diabetic animals supplemented with lutein exhibited normal values of TBARS, T-SH, NP-SH and iNOS as well as SOD and CAT activities particularly in higher dose. Histological analysis further confirmed lutein’s renal protective effects. These results demonstrated clear evidence that lutein offered a significant protective effect against diabetes-induced nephrotoxicity by inhibiting the oxidative and nitrosative process in renal tissue.