OBJECTIVES: To investigate the mechanism by which Guijianyu ameliorates podocyte injury in a mouse model of diabetic kidney disease (DKD) induced by advanced glycation endproducts (AGEs). METHODS: Sixty db/db mouse models of DKD were randomized equally into 5 groups for treatment with saline, Guijianyu extract at 3 doses or irbesartan for 12 weeks, and the changes in renal pathology and structure were observed using transmission electron microscopy, and the expressions of related genes and key proteins were detected using RT-qPCR and immunohistochemistry. In cultured MPC-5 cells incubated with 50 mg/L AGEs-BSA for 24 h, the effect of different concentrations of Guijianyu extract on cell viability was examined with CCK-8 assay; Western blotting was performed to detect the protein expressions of RAGE, VEGFA, TNF-α, NF-κB(p65), IL-6 and caspase-3, and the mRNA expressions of RAGE, NF-κB (p65), VEGFA and IL-6 were detected with RT-qPCR. RESULTS: In mouse models of DKD, treatment with high-dose Guijianyu extract significantly reduced renal expressions of RAGE, VEGFA, NF-κB(p65), and IL-6 proteins and the mRNA expressions of RAGE, NF-κB, and IL-6. In MPC-5 cells, exposure to AGEs significantly reduced cell viability and increased the protein expressions of RAGE, NF‑κB (p65), VEGFA, TNF-α, IL-6 and caspase-3 (P<0.05) and mRNA expressions of RAGE, NF-κB (p65), VEGFA, and IL-6. Treatment with Guijianyu extract obviously improved cell viability and reduced the expressions of RAGE, NF-κB(p65), VEGFA, TNF-α, IL-6, and caspase-3. Furthermore, Guijianyu extract effectively reversed RAGE agonist-induced elevation of protein expressions of RAGE, VEGFA, TNF-α, IL-6, and caspase-3 and mRNA expressions of RAGE, NF-κB (p65), IL-6, and VEGFA in MPC-5 cells. CONCLUSIONS Guijianyu extract ameliorates AGEs-induced mouse renal podocyte injury in DKD by inhibiting the activation of AGEs-RAGE signaling pathway and reducing the expressions of pro-inflammatory cytokines and vascular endothelial growth factors.
Animals ; Glycation End Products, Advanced ; Drugs, Chinese Herbal/pharmacology* ; Mice ; Signal Transduction/drug effects* ; Podocytes/pathology* ; Diabetic Nephropathies/drug therapy* ; Receptor for Advanced Glycation End Products ; Vascular Endothelial Growth Factor A/metabolism* ; Interleukin-6/metabolism* ; Male

OBJECTIVETo evaluate the renal protective effect of Tangshenkang Granule () in a rat model of diabetic nephropathy (DN).

METHODSForty male Sprague-Dawley rats were randomly divided into control, DN, Tangshenkang and benazepril groups. DN model was established in the rats of DN, Tangshenkang and benazepril groups. Tangshenkang Granule solution and benazepril hydrochloride solution were intragastrically administered daily to the rats in the Tangshenkang and benazepril groups for 8 weeks, respectively. Urinary albumin and creatinine were detected. The albumin/creatinine (ACR) was calculated in addition to 24 h urinary protein (24-h UPr), serum creatinine (Scr), blood urea nitrogen (BUN), total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and creatinine clearance rate (Ccr). Right kidneys were harvested for pathological observation using periodic acid-silver methenamine-Masson staining. The average glomerular diameter (DG), average glomerular (AG) and mesangial areas (AM) were measured. The thickness of glomerular basement membrane (TGBM) was detected using transmission electron microscope.

RESULTSCompared with rats in the control group, rats in the DN group showed significantly decreased body weight, increased hypertrophy index, 24-h urinary volume, 24-h UPr, ACR, Scr, BUN, Ccr, blood lipids as well as renal pathological indices including DG, AG, AM, AM/AG and TGBM (P <0.05). Compared with the DN group, the weights of rats in the Tangshenkang and benazepril groups were significantly increased, and the renal hypertrophy indices were significantly decreased (P <0.05). The 24-h urinary volumes, ACR, 24-h UPr, Scr, BUN, Ccr, LDL, DG, AG, AM and TGBM were obviously decreased (P <0.05). Compared with the benazepril group, the Tangshenkang group showed significantly decreased levels of ACR, 24-h UPr, AG and AM (P <0.05).

CONCLUSIONSTangshenkang Granule decreased the urinary protein, attenuated the high glomerular filtration rate and improved lipid metabolism in DN rats, and prevented further injury induced by diabetic nephropathy.

Albuminuria ; complications ; Animals ; Basement Membrane ; drug effects ; metabolism ; Blood Urea Nitrogen ; Body Weight ; drug effects ; Creatinine ; blood ; urine ; Diabetic Nephropathies ; blood ; drug therapy ; physiopathology ; urine ; Disease Models, Animal ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Hypertrophy ; Kidney Function Tests ; Kidney Glomerulus ; drug effects ; pathology ; physiopathology ; Lipid Metabolism ; drug effects ; Lipids ; blood ; Male ; Rats, Sprague-Dawley

PURPOSE: Diabetic nephropathy is a serious complication of type 2 diabetes mellitus, and delaying the development of diabetic nephropathy in patients with diabetes mellitus is very important. In this study, we investigated inflammation, oxidative stress, and lipid metabolism to assess whether curcumin ameliorates diabetic nephropathy. MATERIALS AND METHODS: Animals were divided into three groups: Long-Evans-Tokushima-Otsuka rats for normal controls, Otsuka-Long-Evans-Tokushima Fatty (OLETF) rats for the diabetic group, and curcumin-treated (100 mg/kg/day) OLETF rats. We measured body and epididymal fat weights, and examined plasma glucose, adiponectin, and lipid profiles at 45 weeks. To confirm renal damage, we measured albumin-creatinine ratio, superoxide dismutase (SOD), and malondialdehyde (MDA) in urine samples. Glomerular basement membrane thickness and slit pore density were evaluated in the renal cortex tissue of rats. Furthermore, we conducted adenosine monophosphate-activated protein kinase (AMPK) signaling and oxidative stress-related nuclear factor (erythroid-derived 2)-like 2 (Nrf2) signaling to investigate mechanisms of lipotoxicity in kidneys. RESULTS: Curcumin ameliorated albuminuria, pathophysiologic changes on the glomerulus, urinary MDA, and urinary SOD related with elevated Nrf2 signaling, as well as serum lipid-related index and ectopic lipid accumulation through activation of AMPK signaling. CONCLUSION: Collectively, these findings indicate that curcumin exerts renoprotective effects by inhibiting renal lipid accumulation and oxidative stress through AMPK and Nrf2 signaling pathway.
Albuminuria ; Animals ; Anti-Inflammatory Agents, Non-Steroidal/*therapeutic use ; Curcumin/*pharmacology ; Diabetes Mellitus, Type 2/*metabolism/urine ; Diabetic Nephropathies/complications/*drug therapy/metabolism/pathology ; Gene Expression/drug effects ; Inflammation ; Kidney/drug effects/metabolism/physiopathology ; Kidney Glomerulus/metabolism/physiopathology ; Lipid Metabolism/*drug effects ; Male ; Malondialdehyde/metabolism/urine ; Oxidative Stress/*drug effects ; Rats ; Rats, Inbred OLETF ; Rats, Long-Evans ; Superoxide Dismutase/metabolism

PURPOSE: The aim of this study was to examine the effects of all-trans retinoic acid (ATRA) on diabetic nephropathy. MATERIALS AND METHODS: We measured amounts of urinary albumin excretion (UAE) after administrating ATRA to Otsuka Long-Evans Tokushima Fatty (OLETF) rats. In order to understand the mechanism of action for ATRA, we administrated ATRA to examine its inhibitory action on the production of transforming growth factor-beta1 (TGF-beta1), protein kinase C (PKC), and reactive oxidative stress (ROS) in cultured rat mesangial cells (RMCs). RESULTS: After 16 weeks of treatment, UAE was lower in the ATRA-treated OLETF rats than in the non-treated OLETF rats (0.07+/-0.03 mg/mgCr vs. 0.17+/-0.15 mg/mgCr, p<0.01). After incubation of RMCs in media containing 30 or 5 mM of glucose, treatment with ATRA showed time- and dose-dependent decreases in TGF-beta1 levels and ROS. Moreover, ATRA treatment showed a dose-dependent decrease in PKC expression. CONCLUSION: ATRA treatment suppressed UAE and TGF-beta1 synthesis, which was mediated by significant reductions in PKC activity and ROS production. Our results suggest that ATRA has a potential therapeutic role for diabetic nephropathy.
Animals ; Diabetes Mellitus, Type 2/*complications ; Diabetic Nephropathies/*complications/*drug therapy/pathology ; Mesangial Cells/*metabolism ; Oxidative Stress/drug effects ; Rats ; Rats, Inbred OLETF ; Reactive Oxygen Species/metabolism ; Transforming Growth Factor beta1/analysis/pharmacology ; Tretinoin/*pharmacology/therapeutic use

Diabetic nephropathy (DN) is a common and serious clinical complication of diabetes and presently there are no effective ways to prevent its occurrence and progression. Recent studies show that pentoxifylline (PTX) can improve renal hemodynamics, reduce urinary protein excretion, and alleviate or delay renal failure in DN patients. In this study, we focused on the anti-oxidative stress effect of PTX on alleviating renal damages of DN using rat models. DN rats were established with injection of streptozotocin. Blood glucose, urinary protein excretion, serum cystatin C, renal biopsy, superoxide dismutase (SOD) and malondialdehyde (MDA) in serum and renal homogenate and renal nitrotyrosine levels were analyzed before and 12 weeks after the treatment of PTX. Before treatment, all the DN rats had elevated blood glucose, increased urinary protein excretion and elevated serum cystatin C. Morphologically, DN rats exhibited renal tissue damages, including swelling and fusions of foot processes of podocytes under electron microscope. Masson staining revealed blue collagen deposition in glomeruli and renal interstitium. With treatment of PTX, symptoms and renal pathological changes of DN rats were alleviated. Furthermore, the MDA levels were increased and the SOD levels were decreased in the serum and kidneys of DN rats, and these changes were reversed by PTX. The expression of nitrotyrosine was up-regulated in DN rat model and down-regulated by PTX, indicating that PTX was able to inhibit oxidative reactions in DN rats. PTX could alleviate renal damage in DN, which may be attributable to its anti-oxidative stress activity.
Animals ; Biomarkers ; analysis ; Diabetes Mellitus, Experimental ; drug therapy ; pathology ; Diabetic Nephropathies ; drug therapy ; metabolism ; pathology ; Gene Expression Regulation ; drug effects ; Kidney ; metabolism ; pathology ; Malondialdehyde ; blood ; Oxidative Stress ; drug effects ; Pentoxifylline ; administration & dosage ; pharmacology ; Rats ; Streptozocin ; Superoxide Dismutase ; metabolism ; Tyrosine ; analogs & derivatives ; metabolism

Glomerular hypertrophy is the main pathological characteristic in the early stage of diabetic nephropathy (DN), and its regulatory mechanism is closely related to mammalian target of rapamycin (mTOR) signaling pathway activity. mTOR includes mTOR complex 1 (mTORC1) and mTOR complex 2(mTORC2), in which, the upstream pathway of mTORC1 is phosphatidylinositol-3-kinase (PI3K)/serine-threonine kinase(Akt)/adenosine monophosphate activated protein kinase(AMPK), and the representative signaling molecules in the downstream pathway of mTORC1 are 4E-binding proteins(4EBP) and phosphoprotein 70 S6Kinase(p70S6K). Some Chinese herbal extracts could improve cell proliferation via intervening the expressions of the key molecules in the upstream or downstream of PIK/Akt/mTOR signaling pathway in vivo. As for glomerular mesangial cells(MC) and podocyte, mTOR plays an important role in regulating glomerular inherent cells, including adjusting cell cycle, energy metabolism and matrix protein synthesis. Rapamycin, the inhibitor of mTOR, could suppress glomerular inherent cell hypertrophy, cell proliferation, glomerular basement membrane (GBM) thickening and mesangial matrix deposition in model rats with DN. Some Chinese herbal extracts could alleviate glomerular lesions by intervening mTOR signaling pathway activity in renal tissue of DN animal models or in renal inherent cells in vivo and in vitro.
Animals ; Diabetic Nephropathies ; drug therapy ; enzymology ; genetics ; pathology ; Drugs, Chinese Herbal ; administration & dosage ; Humans ; Hypertrophy ; drug therapy ; enzymology ; genetics ; pathology ; Kidney Glomerulus ; drug effects ; metabolism ; pathology ; Signal Transduction ; drug effects ; TOR Serine-Threonine Kinases ; genetics ; metabolism

OBJECTIVETo demonstrate the effects and mechanisms of Huangkui capsule (HKC) on renal fibrosis in rats with diabetic nephropathy (DN).

METHODRats were randomly divided into 5 groups, the sham-operated group (Sham group, n = 5), the vehicle-given group (Vehicle group, n = 7), the low dose of HKC-treated group (L-HKC group, n = 7), the high dose of HKC-treated group (H-HKC group, n = 7) and the lipoic acid (LA)-treated group (LA group, n = 7). DN models were induced by intraperitoneal injection of streptozotocin (STZ,35 mg x kg(-1)) twice and unilateral nephrectomy. After models were successfully established, the rats in HKC and LA groups were daily administrated with HKC suspensions (0.75, 2 g x kg(-1)) or LA suspensions (60 mg x kg(-1)) respectively, and at the same time, the rats in Vehicle group were daily administrated with distilled water (2 mL) for 8 weeks. All rats were sacrificed at the end of week 8 to collect blood and renal tissues. UAlb, renal function, renal fibrotic morphologic characteristics, as well as oxidative stress (OS)-related markers, the protein expressions of the key signaling molecules in p38 mitogen-activated protein kinase (p38MAPK) signaling pathway, fibrogenic cytokines and inflammatory factors were examined respectively.

RESULTHKC, similar to LA, improved the general state of health, body weight, UAlb, BUN, UA and Alb in DN model rats. Of note, renal fibrosis was ameliorated in HKC groups,especially in H-HKC group which was better than that in LA group. In addition, HKC not only improved the main indexes of OS in the kidney like LA, but also down-regulated the protein expressions of phosphorylated-p38MAPK (p-p38MAPK), transforming growth factor (TGF)-β1 and tumor necrosis factor(TNF)-α in the kidney, whereas, LA only decreased the protein expression of TNF-α in the kidney in DN model rats.

CONCLUSIONHKC, similar to LA, has the actions of anti-OS in vivo. Moreover, HKC could attenuate renal fibrosis by suppressing the activation of p38MAPK signaling pathway and the protein expressions of fibrogenic cytokines and inflammatory factors in the kidney in DN model rats, which is different from LA.

Abelmoschus ; chemistry ; Animals ; Capsules ; Diabetic Nephropathies ; drug therapy ; metabolism ; pathology ; Drugs, Chinese Herbal ; pharmacology ; Fibrosis ; Kidney ; drug effects ; pathology ; MAP Kinase Signaling System ; drug effects ; Male ; Oxidative Stress ; drug effects ; Rats ; Rats, Sprague-Dawley ; p38 Mitogen-Activated Protein Kinases ; antagonists & inhibitors

We aimed to elucidate the effect of bilirubin on dyslipidemia and nephropathy in a diabetes mellitus (DM) type I animal model. Sprague-Dawley rats were separated into control, DM, and bilirubin-treated DM (Bil) groups. The Bil group was injected intraperitoneally with 60 mg/kg bilirubin 3 times per week and hepatoma cells were cultured with bilirubin at a concentration of 0.3 mg/dL. The Bil group showed lower serum creatinine levels 5 weeks after diabetes onset. Bilirubin treatment also decreased the amount of mesangial matrix, lowered the expression of renal collagen IV and transforming growth factor (TGF)-beta1, and reduced the level of apoptosis in the kidney, compared to the DM group. These changes were accompanied by decreased tissue levels of hydrogen superoxide and NADPH oxidase subunit proteins. Bilirubin decreased serum total cholesterol, high-density lipoprotein cholesterol (HDL-C), free fatty acids, and triglycerides (TGs), as well as the TG content in the liver tissues. Bilirubin suppressed protein expression of LXRalpha, SREBP-1, SCD-1, and FAS, factors involved in TG synthesis that were elevated in the livers of DM rats and hepatoma cells under high-glucose conditions. In conclusion, bilirubin attenuates renal dysfunction and dyslipidemia in diabetes by suppressing LXRalpha and SREBP-1 expression and oxidative stress.
Animals ; Bilirubin/pharmacology/*therapeutic use ; Cell Line, Tumor ; Creatine/blood ; Diabetes Mellitus, Experimental/chemically induced/complications/*pathology ; Diabetic Nephropathies/*drug therapy/etiology ; Disease Models, Animal ; Kidney/pathology ; Lipoproteins, HDL/blood ; Liver/metabolism ; Male ; Mice ; Mice, Inbred C57BL ; NADPH Oxidase/metabolism ; Orphan Nuclear Receptors/antagonists & inhibitors/genetics/metabolism ; Oxidative Stress/drug effects ; Rats ; Rats, Sprague-Dawley ; Reactive Oxygen Species/metabolism ; Streptozocin/toxicity ; Triglycerides/analysis/*biosynthesis/blood

Diabetic nephropathy (DN) is a progressive kidney disease that is caused by injury to kidney glomeruli. Podocytes are glomerular epithelial cells and play critical roles in the glomerular filtration barrier. Recent studies have shown the importance of regulating the podocyte actin cytoskeleton in early DN. The phosphoinositide 3-kinase (PI3K) inhibitor, wortmannin, simultaneously regulates Rac1 and Cdc42, which destabilize the podocyte actin cytoskeleton during early DN. In this study, in order to evaluate the reno-protective effects of wortmannin in early DN by regulating Rac1 and Cdc42, streptozotocin (STZ)-induced proteinuric renal disease (SPRD) rats were treated with wortmannin. The albuminuria value of the SPRD group was 3.55 +/- 0.56 mg/day, whereas wortmannin group was 1.77 +/- 0.48 mg/day. Also, the albumin to creatinine ratio (ACR) value of the SPRD group was 53.08 +/- 10.82 mg/g, whereas wortmannin group was 20.27 +/- 6.41 mg/g. Changes in the expression level of nephrin, podocin and Rac1/Cdc42, which is related to actin cytoskeleton in podocytes, by wortmannin administration were confirmed by Western blotting. The expression levels of nephrin (79.66 +/- 0.02), podocin (87.81 +/- 0.03) and Rac1/Cdc42 (86.12 +/- 0.02) in the wortmannin group were higher than the expression levels of nephrin (55.32 +/- 0.03), podocin (53.40 +/- 0.06) and Rac1/Cdc42 (54.05 +/- 0.04) in the SPRD group. In addition, expression and localization of nephrin, podocin and desmin were confirmed by immunofluorescence. In summary, we found for the first time that wortmannin has a reno-protective effect on SPRD rats during the early DN. The beneficial effects of wortmannin in SPRD rats indicate that this compound could be used to delay the progression of the disease during the early DN stage.
Albumins/metabolism ; Androstadienes/*administration & dosage/pharmacology ; Animals ; Creatinine/blood ; Desmin/genetics/metabolism ; Diabetes Mellitus, Experimental/*drug therapy/metabolism/pathology ; Diabetic Nephropathies/*drug therapy/metabolism/pathology ; Disease Models, Animal ; Humans ; Intracellular Signaling Peptides and Proteins/genetics/metabolism ; Kidney/*pathology ; Membrane Proteins/genetics/metabolism ; Phosphatidylinositol 3-Kinases/*antagonists & inhibitors ; Podocytes/*drug effects/metabolism/pathology ; Rats ; Rats, Inbred Strains ; cdc42 GTP-Binding Protein/genetics/metabolism ; rac1 GTP-Binding Protein/genetics/metabolism

BACKGROUNDDiabetic nephropathy is a major cause of renal failure in diabetes mellitus (DM). It has been known that renin-angiotensin system (RAS) blockers have a renal protective effect. This study aimed to investigate whether treatment with angiotensin II receptor blocker, olmesartan, could modify renal hemodynamic variables and vascular structural properties, then attenuate renal injury in streptozotocin (STZ)-induced DM rats.

METHODSDM was induced in male Wistar rats by intraperitoneal administration of STZ. The rats were then randomized to a DM group and an olmesartan treatment (OLM + DM) group. The normal group (non-DM) were administered only citrate buffer. At the end of the 14th week, blood glucose, kidney weight/body weight and urinary protein-to-creatinine ratio were determined. Further, the flow-pressure and pressure-glomerular filtration rate (GFR) relationships were determined for maximally vasodilated, perfused kidneys. From the relationship, 3 indices of vascular structural properties were estimated: slope of flow-pressure (minimal renal vascular resistance, reflecting overall luminal dimensions of preglomerular and postglomerular vasculature), slope of pressure-GFR (glomerular filtration capacity against pressure) and threshold pressure for beginning filtration at pressure-GFR (preglomerular to postglomerular vascular resistance ratio). Kidneys were then perfusion fixed for histological analysis. The renal histopathology was observed by light microscopy.

RESULTSThe body weight of DM rats was lower than that of non-DM rats. Blood glucose, kidney weight/body weight, urinary protein-to-creatinine ratio were significantly greater in DM rats than in non-DM rats. The parameters such as kidney weight/body weight, urinary protein-to-creatinine ratio in OLM + DM rats had dramatically decreased compared with those in DM rats. However, the treatment with olmesartan had no effect on blood glucose levels. The slope of flow-pressure relationship was greater in DM rats than that in non-DM rats (P < 0.05). But the slope of the pressure-GFR relationship was lower in DM rats than that in non-DM rats (P < 0.05) with the x-intercept of the line similar between the two groups. The slope of the flow-pressure relationship was decreased in DM rats group treated with olmesartan (P < 0.05). Moreover, olmesartan significantly increased the slope of the pressure-GFR relationship in DM rats (P < 0.05). The x-intercept of the pressure-GFR relationship reduced following olmesartan in DM rats.

CONCLUSIONSTreatment with olmesartan reduced urinary protein-to-creatinine ratio independent of blood glucose and increased average renal vessel lumen diameter in the perfused kidneys of STZ-induced DM rats, predominantly in preglomerular vessels, and then improved renal excretory capability. These findings were consistent with remodeling of the preglomerular vasculature in our hisological measurements.

Angiotensin II Type 1 Receptor Blockers ; therapeutic use ; Animals ; Blood Glucose ; drug effects ; Diabetes Mellitus, Experimental ; drug therapy ; metabolism ; physiopathology ; Diabetic Nephropathies ; drug therapy ; prevention & control ; Hemodynamics ; drug effects ; Imidazoles ; Kidney ; drug effects ; metabolism ; pathology ; Male ; Organ Size ; drug effects ; Rats ; Rats, Wistar ; Tetrazoles