STZ-induced Diabetic Nephropathy Rats Research Articles

BM-MSCs alleviate diabetic nephropathy in male rats by regulating ER stress, oxidative stress, inflammation, and apoptotic pathways.

Introduction: Diabetic nephropathy (DN), a chronic kidney disease, is a major cause of end-stage kidney disease worldwide. Mesenchymal stem cells (MSCs) have become a promising option to mitigate several diabetic complications. Methods: In this study, we evaluated the therapeutic potential of bone marrow-derived mesenchymal stem cells (BM-MSCs) in a rat model of STZ-induced DN. After the confirmation of diabetes, rats were treated with BM-MSCs and sacrificed at week 12 after treatment. Results: Our results showed that STZ-induced DN rats had extensive histopathological changes, significant upregulation in mRNA expression of renal apoptotic markers, ER stress markers, inflammatory markers, fibronectin, and intermediate filament proteins, and reduction of positive immunostaining of PCNA and elevated P53 in kidney tissue compared to the control group. BM-MSC therapy significantly improved renal histopathological changes, reduced renal apoptosis, ER stress, inflammation, and intermediate filament proteins, as well as increased positive immunostaining of PCNA and reduced P53 in renal tissue compared to the STZ-induced DN group. Conclusion: In conclusion, our study indicates that BM-MSCs may have therapeutic potential for the treatment of DN and provide important insights into their potential use as a novel therapeutic approach for DN.

Diphenyl diselenide ameliorates diabetic nephropathy in streptozotocin-induced diabetic rats via suppressing oxidative stress and inflammation

Oxidative stress and inflammation are implicated in the occurrence and progression of diabetic nephropathy (DN). Diphenyl diselenide (DPDS) is a stable and simple diaryl diselenide with anti-hyperglycemic, anti-inflammatory, and antioxidant activities. However, the effects of DPDS on DN are still unclear to date. Herein, we aimed to explore whether DPDS could improve renal dysfunction in streptozotocin (STZ)-induced diabetic rats and its underlying mechanisms. STZ-induced DN rats were administered with DPDS (5 or 15 mg/kg) or metformin (200 mg/kg) once daily by intragastric gavage for 12 weeks. DPDS supplementation significantly improved hyperglycemia, glucose intolerance, dyslipidemia, and the renal pathological abnormalities, concurrent with significantly reduced serum levels of creatinine, urea nitrogen, urine volume, and urinary levels of micro-albumin, β2-microglobulin and N-acetyl-glucosaminidase activities. Moreover, DPDS effectively promoted the activities of antioxidant enzymes, and reduced the levels of MDA and pro-inflammatory factors in serum and the kidney. Furthermore, DPDS supplementation activated the renal Nrf2/Keap1 signaling pathway, but attenuated the high phosphorylation levels of NFκB, JNK, p38 and ERK1/2. Altogether, the current study indicated for the first time that DPDS ameliorated STZ-induced renal dysfunction in rats, and its mechanism of action may be attributable to suppressing oxidative stress via activating the renal Nrf2/Keap1 signaling pathway and mitigating inflammation by suppressing the renal NFκB/MAPK signaling pathways, suggesting a potential therapeutic approach for DN.

Nephroprotective Effect of Adropinin Against Streptozotocin-Induced Diabetic Nephropathy in Rats: Inflammatory Mechanism and YAP/TAZ Factor.

BackgroundDiabetic Nephropathy remains a major cause of morbidity and mortality in patients suffering from renal dysfunction. This study accessed the nephroprotective role of Adropinin against streptozotocin (STZ) induced diabetic nephropathy in rats and scrutinizes the possible mechanism of action.MethodsSTZ (45 mg/kg) dose was used for inducing diabetic nephropathy (DN) and rats were divided into different groups and received the dose-dependent treatment of Adropinin. Blood glucose level, body weight, tissue weight, antioxidant, renal, hepatic parameters, and cytokines were determined. At the end of the experimental study, renal histopathology was performed.ResultsAdropinin significantly (P<0.001) boosted plasma insulin levels and reduced the blood glucose level. Adropinin considerably increased body weight and reduced kidney weight and kidney hypertrophy. Adropinin significantly (P<0.001) reduced urine outflow, microalbumin, total protein, blood urea nitrogen (BUN), uric acid and increased the creatinine, creatinine clearance. Adropinin significantly (P<0.001) reduced the indole sulfate level in the serum, kidney and reduced in the urine. Adropinin significantly (P<0.001) reduced the total cholesterol, triglyceride, low-density lipoprotein (LDL), very-low-density lipoprotein (VLDL) and increased the level of high-density lipoprotein (HDL). Adropinin significantly (P<0.001) increased the level of antioxidant enzymes such as glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and reduced the level of malonaldehyde (MDA), 8-hydroxy-2ʹ -deoxyguanosine (8-OHdG). Adropinin significantly (P<0.001) reduced the level of interleukin-1β (IL-1β), interleukin-6 (IL-6), transforming growth factor beta (TGF-β) and increased the level of interleukin-10 (IL-10), respectively. Adropinin treatment showed improvement in renal histopathology.ConclusionWe can say that Adropinin showed the nephroprotective effect against the STZ-induced diabetic nephropathy rats via inflammatory and antioxidant pathway.

MicroRNA-30/Cx43 axis contributes to podocyte injury by regulating ER stress in diabetic nephropathy.

BackgroundThe microRNA-30 family plays a critical role in the pathogenesis of podocyte injury. Cx43 plays an essential role in intercellular communication, which is essential for coordinated kidney function. This study was conducted to explore the function of microRNA-30s/Cx43 in podocyte injury in diabetic nephropathy (DN), both in vivo and in vitro.MethodsSD rats were given streptozotocin (STZ) injections to induce DN. Podocytes were incubated in the medium in the presence or absence of high glucose (HG). The effects of the microRNA-30/Cx43 axis on DN and its underlying mechanisms were investigated by TUNEL assay, PAS, immunohistochemical staining, immunofluorescence staining, Western blot, RT-qPCR, RNA interference, and luciferase reporter assay. Podocytes were transfected with microRNA-30 family mimics, microRNA-30 family inhibitors, Cx43 siRNA, and negative controls to detect the effect of the microRNA-30/Cx43 axis. MicroRNA-30 family mimic AAVs, and microRNA-30 family inhibitor AAVs applied to regulate microRNA-30 family expression in the kidneys of the STZ-induced DN model rats to reveal the underlying mechanisms of the microRNA-30/Cx43 axis in DN.ResultsMicroRNA-30 family member expression was downregulated in HG-treated podocytes and the glomeruli of STZ-induced DN rats. Luciferase reporter assays confirmed Cx43 is a directed target of microRNA-30s. The overexpression of microRNA-30 family members attenuated the HG-induced podocyte injury and protected against podocyte apoptosis and endoplasmic reticulum stress (ERS) both in vivo and in vitro. Also, silencing Cx43 expression eased podocyte apoptosis, injury, and ERS induced by a HG+microRNA-30 family inhibitor. Double-immunofluorescence staining assays proved the co-localization of caspase12 and Cx43.ConclusionsThe overexpression of microRNA-30 family members prevents HG-induced podocyte injury and attenuates ERS by modulating Cx43 expression. The microRNA-30/Cx43/ERS axis might be a potential therapeutic target to treat DN.

Overexpression of HOXA-AS2 inhibits inflammation and apoptosis in podocytes via sponging miRNA-302b-3p to upregulate TIMP3.

To clarify the role of HOXA-AS2 in the progression of diabetic nephropathy (DN) and the molecular mechanism. Relative levels of HOXA-AS2 and microRNA-302b-3p (miRNA-302b-3p) in serum and kidney tissues of DN rats induced by STZ administration and controls were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Serum levels of interleukin-1β (IL-1β), Transforming Growth Factor-α (TNF-α), creatinine, and BUN, as well as blood glucose in DN rats administrated with vector or pcDNA-HOXA-AS2 lentivirus, were detected. Dual-Luciferase reporter gene assay was conducted to verify the interaction among HOXA-AS2, miRNA-302b-3p, and TIMP3. At last, the regulatory effects of HOXA-AS2/miRNA-302b-3p/TIMP3 axis on levels of IL-1β and TNF-α, proliferative, and apoptotic rates in podocytes undergoing high-level glucose treatment were explored. HOXA-AS2 was downregulated in STZ-induced DN rats. In vivo overexpression of HOXA-AS2 alleviated kidney injuries in DN rats, manifesting as elevations on serum levels of IL-1β, TNF-α, creatinine, BUN, and blood glucose. HOXA-AS2/miRNA-302b-3p/TIMP3 axis protected DN-induced inflammatory response, proliferation suppression, and apoptosis in podocytes following the high-glucose treatment. HOXA-AS2/miRNA-302b-3p/TIMP3 axis protects inflammatory response, proliferation suppression, and apoptosis in podocytes treated with high-level glucose, thus alleviating the deterioration of DN.

Silencing CCNG1 protects MPC-5 cells from high glucose-induced proliferation-inhibition and apoptosis-promotion via MDM2/p53 signaling pathway.

Diabetic nephropathy (DN) is one of the most serious complications of diabetes mellitus and one of the most important causes of end-stage renal disease, but its pathogenesis has not been elucidated so far, and there is no effective treatment. DN models of rats and MPC-5 cells were established with streptozotocin (STZ) and high glucose (HG) in vivo and in vitro, respectively. Cell markers desmin and nephrin in foot kidney tissue were detected by Western blot. CCNG1 level in vitro was analyzed by Western blot and immunohistochemistry. CCK-8 assay and flow cytometry were conducted to analyze the effect of CCNG1 on HG-treated MPC-5 cells. Apoptosis-related proteins (Bcl-2, Bax and p53), CCNG1, and MDM2 were determined by RT-qPCR and Western blot. The level of nephrin was decreased, while desmin was increased in STZ-induced DN rats and CCNG1 level was also enhanced by STZ. In vitro experiments indicated that MPC-5 cell viability was inhibited and apoptosis was induced by HG and we also found that CCNG1 expression was up-regulated by HG and negatively correlated with MDM2 level. The effects of HG on MPC-5 cell viability, apoptosis, and cell cycle were reversed by silencing CCNG1, but further deteriorated by overexpression of CCNG1. Furthermore, overexpression of MDM2 inhibited HG-induced MPC-5 cell injury and CCNG1 expression. These findings revealed that down-regulation of CCNG1 has protection effects in DN that is mechanistically linked to MDM2-p53 pathways.

Effect of Danggui-Shaoyao-San on renal macrophages in STZ-induced DN rats

Objectives: The present study is to explore the influence of DSS on the proliferation and activation of renal macrophages in the STZ-induced diabetic nephropathy rats. Methods: Seventy rats were grouped according to the random digit table means. 8 rats were randomly selected as the control group. The remaining 62 rats were divided into 5 groups and given a high-fat and high-sugar diet for 4 weeks. Diabetic rats were prepared by intraperitoneal injection of 55 mg/kg STZ. Rats in the DSS groups were given 21 g/kg/day, 14 g/kg/day and 7 g/kg/day DSS separately. The rats in the positive control group were given 6 mg/kg/day TP, while the rats of the model group and control group were received the physiological saline by gastric perfusion directly. Blood glucose, 24 h urine protein, urine urea nitrogen and β2 microglobulin of the rats were measured. And the protein levels of ED-1, MCP-1 and TLR4 in rat kidney were detected by Western Blot. ED-1+/TLR4+, ED-1+/PCNA+ and ED-1+/iNOS+ were detected by immunofluorescence. Results: DSS reduced the levels of blood glucose, 24-h urine protein, urine urea nitrogen and β2 microglobulin and repaired kidney tissue damage of the DN rats. In the WB experiment, DSS clearly decreased the protein expression levels of ED-1, MCP-1, and TLR4 in a dose-dependent manner (p < 0.05). In the immunofluorescence experiment, compared with the model group, the level of ED-1+/TLR4+ in the rats of DSS and TP groups and the level of ED-1+/PCNA+ in the rats of DSS-M group were obviously decreased (p < 0.05). Also, the level of ED-1+/PCNA+ and ED-1+/iNOS+ in the rats of DSS-H and TP groups was decreased evidently (p < 0.01). Conclusion: We inferred that DSS has therapeutic effects on the DN model rats, and its mechanism is likely to be connected with inhibition of macrophage proliferation and activation in rat kidney.

Ophiopogonin D of Ophiopogon japonicus ameliorates renal function by suppressing oxidative stress and inflammatory response in streptozotocin-induced diabetic nephropathy rats.

Ophiopogonin D (OP-D) is the principal pharmacologically active ingredient from Ophiopogon japonicas, which has been demonstrated to have numerous pharmacological activities. However, its protective effect against renal damage in streptozotocin (STZ)-induced diabetic nephropathy (DN) rats remains unclear. The present study was performed to investigate the protective effect of OP-D in the STZ-induced DN rat model. DN rats showed renal dysfunction, as evidenced by decreased serum albumin and creatinine clearance, along with increases in serum creatinine, blood urea nitrogen, TGF-β1, and kidney hypertrophy, and these were reversed by OP-D. In addition, STZ induced oxidative damage and inflammatory response in diabetic kidney tissue. These abnormalities were reversed by OP-D treatment. The findings obtained in the present study indicated that OP-D might possess the potential to be a therapeutic agent against DN via inhibiting renal inflammation and oxidative stress.

Connexin 43‑autophagy loop in the podocyte injury of diabetic nephropathy.

The reduction of podocyte injury is a key strategy in controlling proteinuria, which is the main early clinical manifestation of diabetic nephropathy (DN). Impaired autophagic flux is the primary mechanism responsible for podocyte injury in DN. The aim of the present study was to elucidate the effect of connexin 43 (Cx43) on impaired autophagic flux in podo-cyte injury and to explore its molecular mechanism of action in DN. Sprague-Dawley rats were administered streptozocin (STZ) to construct a DN animal model. Podocytes were incubated in media containing either buffer or high glucose (HG; 30 mM) for variable time periods. The podocytes were then examined and the mechanism of injury was investigated using an Annexin V/PI assay, immunofluorescence staining, western blotting, and RNA interference. In vivo, STZ-induced DN rats with or without Cx43 knockdown were established to observe the role of Cx43 in autophagic flux and podocyte injury. We observed that HG induced podocyte injury, accompanied by increases in Cx43 expression and impaired autophagic flux, as evidenced by the accumulation of LC3II/LC3I and p62. Interestingly, the silencing of Cx43 expression ameliorated autophagic flux impairment and reduced podocyte injury via suppression of the mammalian target of rapamycin pathway. Furthermore, impaired autophagic flux also blocked the degradation of Cx43. In vitro studies indicated that higher numbers of Annexin V/PI-positive podocytes, impaired autophagic flux and increased Cx43 expression were observed in HG-induced podocyte injury relative to the control group. The pathogenic effect of Cx43 on impaired autophagic flux and podocyte injury was also confirmed by Cx43 knockdown. The present study provided preliminary evidence indicating that the interdependence of Cx43 and impaired autophagic flux represents a novel mechanism of podocyte injury in DN. Hence, the Cx43-autophagy loop is a potentially relevant therapeutic target for the treatment of DN.

Ramipril and resveratrol co‐treatment attenuates RhoA/ROCK pathway‐regulated early‐stage diabetic nephropathy‐associated glomerulosclerosis in streptozotocin‐induced diabetic rats

Clinical studies have shown that hyperglycemia can induce early-stage diabetic nephropathy (DN). Furthermore, oxidative stress, tubular epithelial-mesenchymal transition and extracellular matrix accumulation promote the progression of DN to chronic kidney disease and tubulointerstitial fibrosis. It is necessary to initiate treatment at the early stages of DN or even during the early stages of diabetes. In this work, rats with streptozotocin (STZ)-induced diabetes mellitus (DM) presented early DN symptoms within 45 days, and collagen accumulation in the glomerulus of the rats was primarily mediated through the RhoA/ROCK pathway instead of the TGF-β signaling pathway. Resveratrol (15 mg/kg/day) and ramipril (10 mg/kg/day) co-treatment of STZ-induced DN rats showed that glomerulosclerosis in early-stage DN was reversible (P < .05 compared with that in STZ-induced DM rats). The results of this study support early intervention in diabetes or DN as a more efficient therapeutic strategy.

Danzhi Jiangtang Capsule ameliorates kidney injury via inhibition of the JAK-STAT signaling pathway and increased antioxidant capacity in STZ-induced diabetic nephropathy rats.

Danzhi Jiangtang Capsule (DJC), a traditional Chinese medicinal formula, has been used clinically in treating diabetes and diabetic nephropathy (DN). We previously demonstrated that DJC is capable of improving renal function in patients and rats with DN, but the mechanisms underlying these therapeutic benefits of DJC are not quite clear yet. In this study, STZ-induced diabetic rats were orally administered DJC for 8 weeks. Fasting blood glucose, renal function indicators in the serum, renal index, and the expression of proteins related to JAK-STAT signaling pathway were evaluated at the end of the experiment. The kidneys were sliced for pathological histology. Antioxidant status was assessed by measuring SOD, LPO and MDA in serum. The expression levels of COX2, iNOS, SOCS and the phosphorylation status of JAK2, STAT1, and STAT3 in renal tissues were evaluated by Western blot analyses. IL-6, TNF-α, and MCP-1 expression levels in renal tissues were determined using double-antibody sandwich ELISA. Diabetic renal dysfunction and its associated pathologies were ameliorated by DJC treatment. DJC significantly reversed the high expression of COX2 and iNOS in renal tissues. Furthermore, DJC inhibited the JAK2-STAT1/STAT3-SOCS3 signaling pathway, resulting in decreased concentrations of IL-6, TNF-α, and MCP-1. Moreover, the oxidant status in the kidney was substantially ameliorated by DJC treatment. In conclusion, the ability of DJC to ameliorate diabetic renal dysfunction and the associated pathologies of this disease might be due to its antioxidant capacity and suppression of the JAK2-STAT1/STAT3 cascade.

Mulberry leaf polysaccharides suppress renal fibrosis

A mulberry leaf polysaccharide (MLP-1) was prepared and partially characterised, and its anti-renal-fibrosis effects were investigated in streptozotocin (STZ)-induced diabetic nephropathy (DN) rats. MLP-1, with a molecular weight of 2,792,624 Da, consisted of arabinose, glucose, xylose, rhamnose, and mannose in a molar ratio of 1:1.13:2.35:6.74:8.85. Intraperitoneal injection of MLP-1 (2 mL; 0.2–0.4 g/mL) daily for 8 weeks significantly decreased serum insulin, fasting blood glucose, and 24 h urinary albumin, as well as urine protein and connective tissue growth factors, of STZ-induced DN rats. All these results indicated that MLP-1 can effectively inhibit renal fibrosis and potentially treat DN.

Naringin ameliorates diabetic nephropathy by inhibiting NADPH oxidase 4

Naringin, a naturally flavanone glycoside, has been previously demonstrated to alleviate diabetic kidney disease by inhibiting oxidative stress and inflammatory reaction. However, the underlying mechanism of naringin in diabetic nephropathy (DN) has not been fully elucidated. Here, the beneficial effect of naringin on DN in streptozotocin (STZ)-induced DN rats and high glucose (HG)-induced podocytes and its underlying mechanism were elaborated. The result revealed that naringin alleviated STZ-induced renal dysfunction and injury in DN rats, relieved STZ-induced oxidative stress in vivo and inhibited HG-induced apoptosis and reactive oxygen species level i20n vitro. More importantly, naringin inhibited NOX4 expression at mRNA and protein levels in STZ-induced DN rats and HG-induced podocytes. Loss of function indicated that NADPH oxidases 4 (NOX4) down-regulation suppressed apoptosis and reactive oxygen species level in HG-treated podocytes. Take together, this study demonstrated that naringin ameliorates diabetic nephropathy by inhibiting NOX4, contributing to a better understanding of the progression of DN.

Knockdown of Angiopoietin-Like Protein 2 Ameliorates Diabetic Nephropathy by Inhibiting TLR4

Background/Aims: Angiopoietin-like protein 2 (ANGPTL2) was reported to be implicated in the pathogenesis of inflammatory disease. Its role in diabetic nephropathy (DN) remained illdefined. Methods: qRT-PCR and western blot analysis were performed to detect the expressions of ANGPTL2 or TLR4 in streptozotocin (STZ)-induced DN rats and HG-stimulated podocytes. The renal injury index including 24-h proteinuria, blood glucose level, serum creatinine and blood urea nitrogen were measured in DN rats using corresponding commercial kits. The effect of ANGPTL2 knockdown on the secretion or expression of inflammatory cytokines was detected by ELISA or qRT-PCR analysis. The effect of ANGPTL2 knockdown on extracellular matrix (ECM) accumulation was determined by testing TGF-β1, Collagen-IV, fibronectin (FN) and PTEN expression via western blot. Results: ANGPTL2 and TLR4 were both highly expressed in DN rats compared with control group. ANGPTL2 knockdown alleviated renal injury in STZ-induced DN rat model. ANGPTL2 knockdown also suppressed inflammatory cytokines (IL-6, TNF-α, MCP-1, IL-1β) expression and ECM accumulation (TGF-β1, Collagen-IV, FN, PTEN) in HG-induced podocytes. Moreover, ANGPTL2 knockdown led to a significant decrease of TLR4 expression in both DN rat and cell model. Furthermore, TAK-242 treatment exacerbated the inhibitory effect of ANGPTL2 knockdown on inflammatory cytokines expression and ECM accumulation in HG-induced podocytes. Conclusion: ANGPTL2 knockdown ameliorates DN by inhibiting TLR4 expression, an observation contributing to a better understanding of DN pathogenesis.

The renoprotective effects of berberine via the EP4-Gαs-cAMP signaling pathway in different stages of diabetes in rats

Aims: To investigate the renoprotective roles of berberine (BBR) in different stages of diabetic nephropathy (DN) in streptozotocin (STZ)-induced diabetic rats fed a high-sugar and high-fat diet. Methods: Diabetes was induced in mice by intraperitoneal injection of STZ, and the mice were then randomly divided into groups: normal, diabetes, high-sugar and high-fat and BBR (high, median and low dose) groups. The body weight (BW), kidney weight to body weight (KW/BW), blood urea nitrogen, urine total protein to urine creatinine ratio and serum creatinine were measured on different weeks throughout the study. The protein levels of E prostanoid receptor 4 (EP4), Gαs and content of cAMP in the kidney were, respectively, detected by western blot analysis and RIA analysis. Results: In the DN rats, there was remarkable renal damage. BBR restored renal functional parameters, suppressed alterations in histological and ultrastructural changes in the kidney tissues and increased EP4, Gαs and cAMP levels compared with those of the DN model group. In addition, BBR has different therapeutic effects during the different stages of the development of DN, and it works best in the sixth week. Conclusion: These studies demonstrate, for the first time, that BBR exerts renoprotective effects in different stages of DN via EP4- Gαs- AC-cAMP signaling pathway in STZ-induced DN rats fed a high-sugar and high-fat diet.

Berberine regulates the expression of E-prostanoid receptors in diabetic rats with nephropathy

Diabetic nephropathy (DN) is a major cause of morbidity and mortality in diabetic patients. Effective therapies to prevent the development of this disease and to improve advanced kidney injury are required. Berberine (BBR) has preventive effects on diabetes and its complications. This study is to investigate the effects of BBR on the expression of E-prostanoid receptors (EPs) in rats with high-fat diet and streptozotocin (STZ)-induced DN and underlying molecular mechanisms of BBR on DN rats. DN model was induced in male Sprague-Dawley rats with high-fat diet and low dose of STZ injection. BBR (50, 100, 200mg/kg/d) were orally administered to rats after STZ injection and conducted for 8weeks. The levels of interleukin-6 (IL-6) and prostaglandin E2 (PGE2) in renal cortex were measured by enzyme-linked immunosorbent assay. Expression of EPs receptors (EP1-EP4) were determined by western blotting. Remarkable renal damage, hyperglycemia and hyperlipidemia were observed in DN rats. BBR could restore renal functional parameters, suppress alterations in histological and ultrastructural changes in the kidney tissues, improve glucose and lipid metabolism disorders, and increase cAMP levels compared with those of DN model group (Wang et al. in Mol Biol Rep 40:2405-2418, 2013). The level of IL-6 and PGE2 were significantly increased in DN model group compared with normal group, BBR could apparently reduced the level of IL-6 and PGE2. Furthermore, the expression of EP1 and EP3 were both increased and EP4 was lessened in the DN model group compared with normal group, BBR could down-regulate total protein expression of EP1 and EP3 of renal cortex in DN rats and up-regulate the expression of EP4, and there is no significant difference on the expression of EP2 among all groups. These studies demonstrate, for the first time, that BBR exerts renoprotection in high-fat diet and STZ-induced DN rats by modulating the proteins expression of EPs in EP-G protein-cAMP signaling pathway.

The attenuation of Moutan Cortex on oxidative stress for renal injury in AGEs-induced mesangial cell dysfunction and streptozotocin-induced diabetic nephropathy rats.

Oxidative stress (OS) has been regarded as one of the major pathogeneses of diabetic nephropathy (DN) through damaging kidney which is associated with renal cells dysfunction. The aim of this study was to investigate whether Moutan Cortex (MC) could protect kidney function against oxidative stress in vitro or in vivo. The compounds in MC extract were analyzed by HPLC-ESI-MS. High-glucose-fat diet and STZ (30 mg kg−1) were used to induce DN rats model, while 200 μg mL−1 AGEs were for HBZY-1 mesangial cell damage. The treatment with MC could significantly increase the activity of SOD, glutathione peroxidase (GSH-PX), and catalase (CAT). However, lipid peroxidation malondialdehyde (MDA) was reduced markedly in vitro or in vivo. Furthermore, MC decreased markedly the levels of blood glucose, serum creatinine, and urine protein in DN rats. Immunohistochemical assay showed that MC downregulated significantly transforming growth factor beta 2 (TGF-β2) protein expression in renal tissue. Our data provided evidence to support this fact that MC attenuated OS in AGEs-induced mesangial cell dysfunction and also in high-glucose-fat diet and STZ-induced DN rats.

The anti-inflammation effect of Moutan Cortex on advanced glycation end products-induced rat mesangial cells dysfunction and High-glucose–fat diet and streptozotocin-induced diabetic nephropathy rats

Ethnopharmacological relevanceMoutan Cortex (MC, family: Paeonia suffruticosa Andr.) is a well-known traditional herbal medicine that has been shown to hold a protective effect on inflammation in several diseases. However, its anti-inflammatory activity on diabetic nephropathy (DN) has been less reported. The present study was conducted to evaluate the potential attenuation activities of MC on inflammation in AGEs-induced rat mesangial cells dysfunction and high-glucose–fat diet and streptozotocin (STZ)-induced DN rats and explore the possible mechanism underlying its DN effect. Materials and methodsThe inflammation in mesangial cells (HBZY-1) was induced by 200μg/ml advanced glycation end products (AGEs). DN rats model was established by an administration high-glucose–fat diet and an intraperitoneal injection of STZ (30mg/kg). Interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1) level in cell supernatant and rats serum were detected by appropriate kits. A co-culture system of mesangial cells and macrophages was performed to evaluate the migration of macrophages. Immunohistochemical assay was applied to examine transforming growth factor beta1 (TGF-β1), IL-6, MCP-1 and intercellular adhesion molecule-1 (ICAM-1) expression in kidney tissues of rats. Furthermore, western blot analysis was carried out to examine TGF-β1, IL-6, MCP-1, ICAM-1 and RAGE protein expressions in mesangial cells. ResultsPretreatment with MC could significantly inhibit AGEs-induced migration of macrophages in the co-culture system of mesangial cell and macrophage. MC could decrease IL-6 and MCP-1 levels in serum of DN rats in a dose-dependent manner. Furthermore, MC also improved the blood glucose, serum creatinine and urine protein levels. Both immunocytochemistry analysis and western blot analysis showed that MC decreased significantly the over-expression of IL-6, MCP-1, TGF-β1, ICAM-1 and RAGE in mesangial cells or kidney tissues. Additionally, the protein expression of proinflammatory cytokine could also be down-regulated by the pretreatment of RAGE-Ab (5μg/ml). ConclusionThese findings indicated that the extract of MC had an amelioration activity on the inflammation in AGEs-induced mesangial cells dysfunction and high-glucose–fat diet and STZ-induced DN rats. The protective effect might be associated with the intervention of MC via target of RAGE. These findings suggested that MC might be a benefit agent for the prevention and treatment of DN.