Early Diabetic Nephropathy In Rats Research Articles

Sacubitril/Valsartan Improves Progression of Early Diabetic Nephropathy in Rats Through Inhibition of NLRP3 Inflammasome Pathway.

PurposeDiabetic nephropathy (DN), a global disease, is the leading cause of end-stage renal disease. There is a lack of specific treatment for this disease, and early intervention in disease progression is essential. In this paper, we used a rat model of early diabetic nephropathy to explore the therapeutic mechanism of sacubitril/valsartan in rats with early diabetic nephropathy.Materials and MethodsRats were grouped into 1 normal group; 2. Model group (DN group): STZ (45 mg/kg/d) induced early diabetic nephropathy rats; 3. Sac group: DN rats + Sac group (orally, 60 mg/kg/d) for 6 weeks. After 6 weeks, the levels of serum albumin (ALB), glucose (GLU), creatinine (Cr), urea nitrogen (BUN) and 24-h urinary protein excretion were measured. In renal tissue homogenates, NLRP3 inflammasome, proinflammatory factors IL1-β and TNF-α, oxidative stress MDA and pro-fibrotic cytokine TGF-β1 were performed. Histological analysis of kidneys by hematoxylin and eosin (HE), PAS and Masson trichrome staining.Results1. Sacubitril/valsartan (Sac) significantly improved renal hypertrophy, proteinuria and serum albumin levels in rats with early diabetic nephropathy (P < 0.001), and decreased GLU, Scr (P<0.001), and BUN levels (P < 0.01).2. Light microscopy of renal tissues showed glomerular hypertrophy and interstitial inflammatory cell infiltration, and mean glomerular area (MGA) and mean glomerular volume (MGV) were crucially increased in early diabetic nephropathy (P < 0.001), and the Sac group showed reduced renal pathology and improved MGA and MGV (P < 0.001).3. Kidney tissue homogenate levels of NLRP3, Caspase-1, IL1-β, TNF-α, MDA and TGF-β1 were critically, increased in DN rats (P < 0.001), and SOD was significantly decreased. All these indicators above were improved after treatment (P < 0.0001).ConclusionNlrp3-inflammasome promote progression of diabetic nephropathy through inflammation, fibrosis and oxidative stress; sacubitril/valsartan ameliorated early diabetes-induced renal damage by inhibiting NLRP3 pathway activation.

Celastrol slows the progression of early diabetic nephropathy in rats via the PI3K/AKT pathway

BackgroundDiabetic nephropathy serves as one of the most regular microvascular complications of diabetes mellitus and is the main factor that causes end-stage renal disease and incident mortality. As the beneficial effect and minute adverse influence of Celastrol on the renal system requires further elucidation, the renoprotective function of Celastrol in early diabetic nephropathy was investigated.MethodsIn high-fat and high-glucose diet/streptozotocin-induced diabetic rats which is the early diabetic nephropathy model, ALT, AST, 24 h urinary protein, blood urea nitrogen, and serum creatinine content were observed. Periodic acid-Schiff staining, enzyme-linked immunosorbent assay, immunohistochemical analysis, reverse transcription-polymerase chain reaction, and western blot analysis were used to explore the renoprotective effect of Celastrol to diabetic nephropathy rats and the underlying mechanism.ResultsHigh dose of Celastrol (1.5 mg/kg/d) not only improved the kidney function of diabetic nephropathy (DN) rats, and decreased the blood glucose and 24 h urinary albumin, but also increased the expression of LC3II and nephrin, and downregulated the expression of PI3K, p-AKT, and the mRNA level of NF-κB and mTOR.ConclusionCelastrol functions as a potential therapeutic substance, acting via the PI3K/AKT pathway to attenuate renal injury, inhibit glomerular basement membrane thickening, and achieve podocyte homeostasis in diabetic nephropathy.

Effect of Levosimendan, an Inodilator, on Streptozotocin‐Induced Diabetic Nephropathy in Rats

Levosimendan, an inodilator, was shown to have a renal protective effect in different models of kidney dysfunction in experimental animals and in patients with heart failure. The aim of this study was to examine the effect of levosimendan on streptozotocin‐induced early diabetic nephropathy. Male Sprague Dawley rats (n = 24, 320–400 g) were randomly distributed into four groups and treated for 6 weeks. Groups 1 and 3 received either vehicle or levosimendan (1 mg/kg/day) for the last three weeks, respectively. Groups 2 and 4 were rendered diabetic by a single i.p. injection of streptozotocin (60 mg/kg) and were treated as in groups 1 and 3, respectively. At the end of the experiment, rats were placed in metabolic cages and urine was collected for biochemical analysis. Rats were then anesthetized and blood samples collected for biochemical analysis. Kidneys were removed for histopathology. In the untreated diabetic group, there was a significant decrease in body weight, polyuria and increased relative kidney weight. There was increased urinary albumin/creatinine ratio (UACR), 24 hour (h) albumin level and N‐acetyl‐β‐D‐glucosaminidase (NAG)/creatinine ratio (UNCR). Streptozotocin did not cause a significant effect on creatinine clearance when adjusted to body weight. In addition, diabetes was associated with increased oxidative stress [reduced plasma total antioxidant capacity (TAC) and catalase activities]. Kidneys from streptozotocin‐treated rats showed focal clear renal tubular cells affecting proximal convoluted tubules and focal mild interstitial fibrosis at the cortico‐medullary junction. Levosimendan significantly attenuated the reduction in body weight, polyuria and the increase in relative kidney weight. In addition, it significantly attenuated the increase in UACR, urinary 24 h albumin level and UNCR in diabetic rats. It also significantly mitigated the decrease in plasma TAC and catalase activities in diabetic rats. Rats in the diabetic group treated with levosimendan showed less clear cell changes but similar interstitial fibrosis when compared with the untreated diabetic group. This study shows that levosimendan ameliorated some of the changes seen in streptozotocin‐induced early diabetic nephropathy in rats. This could be partly due to its antioxidative effects.Support or Funding InformationSupported by an internal grant from Sultan Qaboos University (IG/MED/PHAR/18/01)

Effect of levosimendan, an inodilator, on streptozotocin-induced diabetic nephropathy in rats

This study examined the effect of levosimendan on streptozotocin-induced early diabetic nephropathy. Rats were distributed into four groups and treated for six weeks. The first and third group received either vehicle or levosimendan (1 mg/kg/day) for the last three weeks, respectively. The second and fourth groups were rendered diabetic by a single intraperitoneal injection of streptozotocin (60 mg/kg) and were treated as the first and third groups, respectively. In the untreated diabetic group, there was a significant decrease in body weight, polyuria and hyperglycemia as well as, increased urinary albumin/creatinine ratio (UACR) and N-acetyl-β-D-glucosaminidase (NAG)/creatinine ratio (UNCR) with no change in creatinine clearance. In addition, diabetes was associated with increased oxidative stress as evidenced by reduced plasma total antioxidant capacity (TAC) and catalase activity and increased plasma malondialdhyde (MDA) and the inflammatory marker, tumor necrosis factor-alpha, (TNF-α). Kidneys from streptozotocin-treated rats showed focal clear renal tubular cells affecting proximal convoluted tubules and mild interstitial fibrosis at the cortico-medullary junction. Levosimendan significantly attenuated the streptozotocin-induced physiological and biochemical changes and there was less clear renal tubular cells. This study shows that levosimendan ameliorated some of the changes seen in streptozotocin-induced early diabetic nephropathy in rats. This could be partly due to its antioxidative and anti-inflammatory effects.

EXPLORATION OF PROTECTIVE EFFECT OF HYDROALCOHOLIC EXTRACT OF ALSTONIA SCHOLARIS BARK IN STZ-INDUCED EARLY DIABETIC NEPHROPATHY MODEL IN RATS

Alstonia scholaris (fam. Apocynaceae) is an indigenous plant used traditionally for the treatment of diabetes and associated complications. However the nephroprotective potential of the plant is not scientifically evaluated. Objective of the present was to investigate renal protective activity of hydroalcoholic extract of A. scholaris bark (HEAS) in streptozotocin (STZ)-induced early diabetic nephropathy in rats and to focus on its possible mechanism of action. Experimental diabetes was induced in Wistar rats using single intraperitoneal injection of streptozotocin (65 mg/kg). Animals were divided in five groups (n=6) and treated with 150 mg/kg and 300 mg/kg HEAS for 4 weeks. At the end of study period, fasting blood glucose, blood urea nitrogen (BUN), serum creatinine, total proteins, serum albumin, serum insulin and glycosylated haemoglobin, superoxide dismutase, catalase, reduced glutathione and MDA in kidney were evaluated. Urine was analyzed for albumin, total proteins and creatinine clearance. Kidney and pancreas were subjected for histopathology. Significant decrease in fasting blood glucose, creatinine, albumin, BUN, total proteins and urinary total proteins was observed. Significant improvement in serum insulin, glycosylated Hb, oxidative stress parameters of kidney including superoxide dismutase, catalase and reduced glutathione has been observed in HEAS treated diabetic rats. Histopathology of kidney and pancreatic tissues showed structural improvement. Present study has revealed that HEAS prevented the progression of diabetic nephropathy in STZ-diabetic rats by improving the disturbed glucose homeostasis and by amelioration of renal oxidative stress.

Effect of tocilizumab, an interleukin-6 inhibitor, on early stage streptozotocin-induced diabetic nephropathy in rats.

The aim of this study was to examine the effect of tocilizumab, an interleukin-6 (IL-6) inhibitor on streptozotocin-induced diabetic nephropathy. Male Sprague-Dawley rats (n = 36) were distributed into six groups and treated for 4weeks. Groups 1, 3, 5 received either saline, tocilizumab (2mg/kg), or tocilizumab (8mg/kg) injection intraperitoneally (i.p.), every 2weeks, respectively. Groups 2, 4, 6 were rendered diabetic by a single i.p. injection of streptozotocin (65mg/kg) and were treated as in groups 1, 3, 5, respectively. Biochemical parameters were measured in plasma, urine, and kidneys. In the untreated diabetic group, there was a significant decrease in body weight, polyuria, and increased kidney weight. There was increased urinary albumin/creatinine ratio (UACR) and N-acetyl-β-D-glucosaminidase (NAG)/creatinine ratio (UNCR). Streptozotocin also induced a significant increase in creatinine clearance. In addition, diabetes was associated with increased oxidative stress [reduced renal glutathione reductase (GR), superoxide dismutase (SOD), catalase activities, and increased malondialdhyde (MDA)] and increased plasma tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and nitric oxide (NO) concentrations. Kidneys from streptozotocin-treated rats showed marked vacuolation of the proximal tubular epithelium with focal tubular necrosis and the glomeruli showing increase in mesangial cells. Tocilizumab significantly mitigated the increase in UACR and UNCR, renal MDA, plasma TNF-α, IL-6 and NO levels, and the decrease in renal SOD and catalase activities in diabetic rats. Tocilizumab did not significantly improve creatinine clearance; however, it attenuated the histopathological changes induced by streptozotocin. This study shows that tocilizumab was able to ameliorate some of the changes seen in streptozotocin-induced early diabetic nephropathy in rats. This is mainly due to its anti-inflammatory and antioxidative effects.

Platelet Microparticles Mediate Glomerular Endothelial Injury in Early Diabetic Nephropathy.

Glomerular endothelium dysfunction, which plays a crucial role in the pathogenesis of early diabetic nephropathy, might be caused by circulating metabolic abnormalities. Platelet microparticles, extracellular vesicles released from activated platelets, have recently emerged as a novel regulator of vascular dysfunction. We studied the effects of platelet microparticles on glomerular endothelial injury in early diabetic nephropathy in rats with streptozotocin-induced diabetes and primary rat glomerular endothelial cells. Isolated platelet microparticles were measured by flow cytometry. Plasma platelet microparticles were significantly increased in diabetic rats, an effect inhibited in aspirin-treated animals. In cultured glomerular endothelial cells, platelet microparticles induced production of reactive oxygen species, decreased nitric oxide levels, inhibited activities of endothelial nitric oxide synthase and SOD, increased permeability of the glomerular endothelium barrier, and reduced thickness of the endothelial surface layer. Conversely, inhibition of platelet microparticles in vivo by aspirin improved glomerular endothelial injury. Further analysis showed that platelet microparticles activated the mammalian target of rapamycin complex 1 (mTORC1) pathway in glomerular endothelial cells; inhibition of the mTORC1 pathway by rapamycin or raptor siRNA significantly protected against microparticle-induced glomerular endothelial injury in vivo and in vitro. Moreover, platelet microparticle-derived chemokine ligand 7 (CXCL7) contributed to glomerular endothelial injury, and antagonizing CXCL7 using CXCL7-neutralizing antibody or blocking CXCL7 receptors with a competitive inhibitor of CXCR1 and CXCR2 dramatically attenuated such injury. These findings demonstrate a pathogenic role of platelet microparticles in glomerular endothelium dysfunction, and suggest a potential therapeutic target, CXCL7, for treatment of early diabetic nephropathy.

Protective effects of tacrolimus on podocytes in early diabetic nephropathy in rats.

The aim of the present study was to investigate the protective effect of tacrolimus on early podocyte damage in rats with diabetic nephropathy (DN). A total of 38 normal male Sprague‑Dawley rats were randomly divided into four groups: Normal control group (group N; n=8), DN group (n=10), tacrolimus (FK506) treatment group (group F; n=10), benazepril (Lotensin) treatment group (group L; n=10). The rats in groups DN, F and L were administered with streptozotocin (STZ; 60mg/kg) by intraperitoneal injection to establish the diabetic rat model. After 4weeks, the diabetic rat model was established, and rats in the different groups were administered intragrastically with the respective drugs. Blood glucose (BS), body weight (BW) and 24‑h urine protein were detected every 4weeks, serum creatinine (SCr), blood urea nitrogen (BUN) and kidney weight/body weight (KW/BW) were measured at the end of the 8weeks of drug treatment. Renal pathological changes were observed under a light microscope and electron microscope. Expression of nephrin, which is a podocyte‑specific marker, was detected using western blot analysis. The results showed that the levels of SCr, BUN, KW/BW and 24‑h urine protein in groups D, F and L were significantly higher, compared with those in group N (P<0.05). No significant differences were found between groups F and L for the above indicators, with the exception of BS. However, all indices were significantly lower, compared with those in group DN (P<0.05). Renal pathological expression was normal in group N under light microscopy. There were significant increases in the glomerular volume, proliferative mesangial cells, width of the mesangial area and thickness of the basement membrane in group DN, however, all the above pathological characteristics were reduced in groups F and L, compared with group DN (P<0.05). No significant difference was found between groups F and L. A widened glomerular basement membrane, and disorder, widening and fusion of podocyte processes were observed under the electron microscope in group DN, however, these were reduced in groups F and L, compared with group DN (P<0.05). The results of the western blot analysis showed that the expression of nephrin decreased by 60.1% in group DN, compared with group N, and significant recovery in the expression of nephrin was observed in groups F and L (P<0.05). Tacrolimus reduced urinary protein and slowed the progression of DN, partially by recovering the protein expression of nephrin in the renal tissue of diabetic rats, and maintaining the integrity of the structure and function of podocytes.

Ameliorative effect of eprosartan on high-fat diet/streptozotocin-induced early diabetic nephropathy in rats

Diabetic nephropathy becomes the single most frequent cause of end-stage renal disease. The present study aimed therefore to investigate possible protective effect of eprosartan, an angiotensin II type 1 receptor blocker, on high-fat diet/streptozotocin-induced early diabetic nephropathy in rats and various mechanisms underlie this effect. Male Wistar rats with type 2 diabetes induced by high-fat diet/streptozotocin were treated with eprosartan at the dose levels of 30 and 60mg/kg daily for 5 weeks. Eprosartan induced a nephroprotective effect as evident by the significant decrease in serum creatinine, urea, total cholesterol, triglycerides and glucose levels, urinary albumin excretion and kidney index as well as renal levels of malondialdehyde and nitric oxide products (nitrite/nitrate), in addition to angiotensin II, inducible nitric oxide synthase, transforming growth factor-β1 and collagen IV expressions with a concurrent increase in renal levels of reduced glutathione and catalase activity compared to diabetic untreated rats. Histopathological examination confirmed the renoprotective effect of eprosartan. In conclusion, eprosartan protects rats against high-fat diet/streptozotocin-induced early diabetic nephropathy possibly, in part, through its antioxidant effect as well as by abrogating the overexpression of angiotensin II, inducible nitric oxide synthase, transforming growth factor-β1 and collagen IV.

Evaluation of the renal hemodynamic changes in early diabetic nephropathy rats by color Doppler ultrasound and its correlation with podocyte damage

Objective To evaluated the renal hemodynamic changes in early diabetic nephropathy rats by color Doppler ultrasound and its correlation with podocyte damage.Methods Twenty male SD rats were randomly divided into 2 groups:,control group and diabetic nephropathy group.After 8 weeks,the systolic peak velocity (Vmax),diastolic minimum velocity (Vmin) and resistance index (RI) were measured by color Doppler ultrasound,the pathological changes in kidney tissues were obseved by HE staining,nephrin deposits were observed by immunofluorescence,and the nephrin mRNA expression in the renal cortex were detected by RT-PCR method.The difference of those results between two groups were compared,and the relationship between nephrin mRNA expression and index of renal hemodynamic were analysed.Results Compared with rats in control group,the Vmax and Vmin was lower among rats in diabetic nephropathy group [(16.63 ± 2.85)cm/s vs (24.16 ± 3.35)cm/s,P ＜0.001 and (5.41 ± 1.11)cm/s vs (9.87 ± 2.26) cm/s,P ＜0.001].However,the RI was higher than that of control group (0.73 ± 0.14 vs 0.57 ± 0.12,P =0.034).Bigger glomerular volume,increased mesangial matrix,increased mesangial cells,and visible focal lymphocytic or mononuclear cell infiltrated were observed in diabetic nephropathy group.The expressions of nephrin were lower in the cortex of renal in diabetic nephropathy group compared to control group (0.276 ± 0.015 vs 0.507 ± 0.024,P ＜0.001).Correlation analysis suggested nephrin mRNA expression was positively correlated with the Vmax and Vmin (r =0.931 and r =0.944,all P ＜0.001),and negatively correlated with RI (r =0.786,P ＜0.001).Conclusions Renal hemodynamic changes assessed by color Doppler ultrasound associated with podocyte damage in diabetic nephropathy rat,which is a noninvasive method of evaluation of early kidney damage. Key words: Ultrasonography; Diabetic nephropathy; Hemodynamics; Podocyte

Ultrasound-Mediated Microbubble Destruction Increases Renal Interstitial Capillary Permeability in Early Diabetic Nephropathy Rats

Diabetic nephropathy (DN) is defined as persistent proteinuria corresponding to a urinary albumin excretion rate >300 μg/mg in the absence of other non-diabetic renal diseases. The aim of this study was to determine if ultrasound (US)-mediated microbubble (MB) destruction could increase renal interstitial capillary permeability in early DN rats. Diabetes was induced with streptozotocin. DN rats presented with mild micro-albuminuria 30 d after onset of diabetes. DN rats (N = 120) were divided into four groups that received Evans blue (EB) followed by: (i) no treatment (control group); (ii) continuous ultrasonic irradiation for 5 min (frequency = 7.00 MHz, mechanical index = 0.9, peak rarefactional pressure = 2.38 MPa: US group); (iii) microbubble injection (0.05 mL/kg: MB group); and (iv) both ultrasound and microbubble injection (US + MB group). Another 8 DN rats were subjected to ultrasound and microbubbles and then injected with EB after 24 h (recovery group). EB content, EB extravasation and E-selectin mRNA and protein expression significantly increased, and interstitial capillary walls became discontinuous in the US + MB group. Neither hemorrhage nor necrosis was observed on renal histology. Urine samples were collected 24 h post-treatment. There was no hematuria, and the urinary albumin excretion rate did not increase after ultrasound-microbubble interaction detected by urinalysis. EB content returned to the control group level after 24 h, as assessed for the recovery group. In conclusion, ultrasound-mediated microbubble destruction locally increased renal interstitial capillary permeability in DN rats, and should be considered a therapy for enhancing drug and gene delivery to the kidney in the future.

Protective activity profile of herbomineral medicine in early diabetic nephropathy rats: Restoration of kidney antioxidants, hemodynamics and suppression of proinflammatory mediators

The effect of Shakrino, a herbomineral medicine (HMM)) on early diabetic nephropathy in rats was evaluated. The occurrence of early diabetic nephropathy (DN) in rats treated with streptozotocin was revealed by hyperglycemia, depleted liver glycogen, decreased glucose uptake by peripheral tissue, impaired renal function, increased lipid peroxidation and decreased antioxidants in kidney. These changes were associated with increased total urine output, urinary albumin excretion rate, urinary albumin to creatinine ratio, increased relative kidney weight, increased arterial blood pressure, decreased glomerular filtration rate and urinary creatinine in DN rat. HMM treatment (200 and 400mg/kg, p.o., 4 weeks) lowered blood glucose, glycosylated haemoglobin, creatinine, blood urea nitrogen, lipid profiles, serum albumin and total urine output, urinary albumin excretion rate, urinary albumin to creatinine ratio, relative kidney weight, increased urinary creatinine and GFR, and also restored depleted antioxidants, decreased malonolaldehyde formation in kidney of DN rats. Histoarchitecture study showed dense mesangial matrix in glomeruli of DN rats, which were improved by HMM treatment. The protective effect of HMM may be due to the presence of antioxidants like gallic acid, quercetin, β-sitosterol, Jamboline, ellagic acid, gymnemic acid B, α-amyrin and polyphenols.

Effect of Qutantongluo decoction on expression of TGF-β1 in renal tissue of early diabetic nephropathy rats

Objective To observe the effects of Qutantongluo decoction on the expression of TGF-β1 in renal tissue of diabetic nephropathy(DN) rats,which can help to understand the mechanism of action.Methods The rats models of diabetic nephropathy were established by injecting with streptozotocin intraperi-toneally.All Wistar rats were randomly divided into 6 groups:the normal control group,the model control group,Benazepril Hydrochloridec group ( 1 mg/kg ·d-1 ),Qutantongluo decoction low dose group (3 g/kg ·d-1 ),Qutantongluo decoction median dose group (4.5 g/kg · d-1 ),and Qutantongluo decoction high dose group (6 g/kg · d-1 ).Rats in the normal control group and the model control group were given celiac perfusion of distilled water once at the same time and dose.All the rats were gavaged once daily for 8 weeks.The expression of TGF-β1 at the level of gene and protein in renal tissue were tested by immunohistochemistry and RT-PCR methods.Results Compared with the model control group(2.79±0.22),the expression of TGF-β1 at the level of protein in renal tissue of Benazepril Hydrochloridec group (1.55 ±0.12)and the Qutantongluo decoction low dose group ( 1.54± 0.16),Qutantongluo decoction median dose group (1.49 ± 0.17),Qutantongluo decoction high dose group(l.39±0.25) decreased significantly (P＜0.05).Compared with the model control group (0.35±0.07),the expression of TGF-β1 mRNA in renal tissue of Benazepril Hydrochloridec group(0.35± 0.07)and the Qutantongluo decoction low dose group(0.39±0.03),Qutantongluo decoction median dose group (0.35± 0.06),Qutantongluo decoction high dose group (0.32± 0.07) decreased significantly (P＜0.05).Conclusion Qutantongluo decoction can down regulate the expression of TGF-β1 in kidney,which may be one of the mechanisms of Qutantongluo decoction effectiveness in clinical treatment of diabetic nephropathies. Key words: Diabetic nephropathies; Qutantongluo decoction; TGF-β1

Artemisia campestris leaf extract alleviates early diabetic nephropathy in rats by inhibiting protein oxidation and nitric oxide end products

Chronic hyperglycemia in diabetes leads to free radicals overproduction, which contributes to the development of diabetic nephropathy. The present study investigated the effects of Artemisia campestris (Ac), a plant of the Asteraceae family, on renal impairment and oxidative stress in alloxan-induced diabetic rats. Diabetes was induced by a single subcutaneous injection of alloxan (120mgkg−1) in rats. Ac (200mgkg−1) was administered to diabetic rats for 3 weeks. Diabetic renal injury was associated with hyperglycemia, increased serum creatinine, urea and uric acid levels. This nephropathophysiology was associated with a surproduction of nitric oxide (NO), malondialdehyde (MDA) and advanced oxidation protein products (AOPP) levels and a decrease in glutathione (GSH) levels. In addition, hyperglycemia increased the activities of antioxidant enzymes, such as catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx), in the kidney of diabetic rats. Treatment with Ac effectively ameliorated diabetic renal dysfunction by reducing oxidative and nitrosative stress. Histological studies also supported the experimental findings. The results suggested that Ac might act as a beneficial agent against renal dysfunctions developed in alloxan-induced diabetes.

Protective effect of herbomineral formulation (Dolabi) on early diabetic nephropathy in streptozotocin-induced diabetic rats

The effect of a herbomineral formulation (HMF) on early diabetic nephropathy was investigated. Diabetes was induced in Wistar rats by administering streptozotocin (55 mg/kg, intraperitoneally). The occurrence of early diabetic nephropathy in rats was revealed by high plasma glucose and depleted liver glycogen, decreased glucose uptake by peripheral tissue, impaired renal function, increased antioxidants and lipid peroxidation in kidney. These changes were accompanied by elevated malondialdehyde, glutathione and superoxide dismutase activity in kidney. Furthermore, increased total urine volume, urinary albumin excretion rate, urinary albumin to creatinine ratio, increased relative kidney weight, decreased glomerular filtration rate (GFR) and urinary creatinine were also observed in diabetic nephropathy rats. HMF treatment significantly lowered blood glucose, glycosylated hemoglobin, creatinine, blood urea nitrogen, triglycerides, total cholesterol, serum albumin level, total urine volume, urinary albumin excretion rate, urinary albumin to creatinine ratio and relative kidney weight, and increased urinary creatinine and GFR. Altered levels of antioxidants, viz. lipid peroxidation, glutathione and superoxide dismutase (SOD), in kidney of diabetic nephropathy rats were restored. Histopathological findings indicated dense mesangial matrix in the glomeruli of diabetic nephropathy rats, which may be due to over-activation of matrix metalloproteinases and was reduced following HMF treatment. Our experimental findings clearly demonstrate that HMF has an ability to prevent the progression of early diabetic nephropathy. Such protective effect of HMF might be due to the presence of flavonoids (catechin, quercetin, rutin) and triterpene saponins (oleanolic acid and gymnemic acid) which are known to possess potent antioxidant properties.

Influence of experimental early diabetic nephropathy on the functional subtypes of renal α1‐adrenoceptor in spontaneously hypertensive rats (SHR)

This study investigated the impact of early diabetic nephropathy (EDN) on the functional population of renal α1‐adrenoceptors in SHR rats. One week after streptozotocin, EDN was confirmed by hyperglycemia (14.8±2.3 vs 5.7 ±0.6 mg/dL), raised creatinine clearance (4.2±0.10 vs 0.5±0.07 mL/min/100g), albumin‐creatinine ratio (94.6±3.7 vs 39.4±2.6 µg albumin/mg creatinine) and fractional excretion of Na+ (1.2±0.01 vs 0.4±0.01 %) compared to non‐diabetic (NDN) rats. In acute studies, renal vasoconstrictions caused by renal nerve stimulation and intrarenal noradrenaline, phenylephrine and methoxamine were determined in the presence and absence of intrarenal amlodipine (AMP), 5‐methylurapidil (MEU), chloroethylclonidine (CEC) and BMY 7378. In both NDN and EDN rats, the renal vasoconstrictions were attenuated by all antagonists (AMP‐ NDN, 5‐15% and EDN, 8‐20%; MEU‐ NDN, 5‐14% and EDN, 9‐14%; BMY 7378‐ NDN, 5‐10% and EDN, 5‐8%). CEC enhanced these responses in EDN (5‐10%) but did not cause any effect in NDN SHR rats. The data showed that α1A and α1D are the renal functional α1‐adrenoceptors in SHR rat irrespective of the presence of EDN. A minor contribution of pre‐synaptic α1B‐adrenoceptors was observed in the EDN group.

Depressive status does not alter renal oxidative and immunological parameters during early diabetic nephropathy in rats

Depression is frequently observed among patients with diabetes and depressive status has been associated to activation of inflammatory processes, suggesting a role of depression in the inflammatory events observed in diabetes. To test that proposal, it was studied the effect of depression induced by forced swimming test (FST) on the evolution of early diabetic nephropathy. Diabetes was induced by streptozotocin injection. Rats were submitted to FST for 15 days. Struggle time was determined during FST and motor activity previously to FST. Nitric oxide, malondialdehyde, reduced glutathione and catalase activity were measured in kidney homogenates by enzymatic and biochemical methods. Superoxide anion, monocyte/macrophage (ED-1 positive cells) and RAGE were determined by hystochemical and immunohistochemical methods. Diabetic rats had decreased struggle time and locomotor activity at day 1 of FST. Both control and diabetic rats had those parameters decreased at day 15. Renal oxidative stress, RAGE expression and ED-1 cells were observed increased in diabetic animals. Those parameters were not significantly altered by FST. The depressive status does not alter oxidative and immune parameters during the early renal changes of diabetic nephropathy.

α1B-Adrenoceptors mediate adrenergically-induced renal vasoconstrictions in rats with renal impairment

This study examined whether alpha1B-adrenoceptors are involved in mediating adrenergically-induced renal vasoconstrictor responses in rats with pathophysiological and normal physiological states. Male Wistar Kyoto and spontaneously hypertensive rats were induced with acute renal failure or experimental early diabetic nephropathy by cisplatin or streptozotocin, respectively. Cisplatin-induced renal failure was confirmed by impaired renal function and pronounced tubular damage. Experimental early diabetic nephropathy was confirmed by hyperglycemia, changes in physiological parameters, and renal function. The hemodynamic study was conducted on anesthetized rats after 7 d of cisplatin (renal failure) and 4 weeks of streptozotocin (experimental early diabetic nephropathy). In the rats with renal failure and experimental early diabetic nephropathy, there were marked reductions in their baseline renal blood flow (P<0.01). The baseline mean arterial blood pressure was either unaltered or lower (all P>0.05) in the renal failure and experimental early diabetic nephropathy rats, respectively, as compared to their non-renal failure and non-diabetic nephropathy controls. In the rats with renal impairment, chloroethylclonidine caused either accentuation or attenuation (all P<0.01) of the renal vasoconstrictor responses elicited by the adrenergic stimuli. However, in the non-renal failure and in the non-diabetic nephropathy rats, chloroethylclonidine did not cause any alteration in such responses (P>0.05). This study demonstrated the presence of functional alpha1B-adrenoceptors that mediated the adrenergically-induced renal vasoconstrictions in rats with renal impairment, but not in rats with normal renal function.

Protective effects of bendazac lysine on early experimental diabetic nephropathy in rats

To investigate the preventive and protective effects of bendazac lysine (BDL) on experimental early diabetic nephropathy (DN) rats. After an early DN model was induced by streptozotocin, rats were administered BDL at doses of 100, 200, and 400 mg/kg for 8 weeks. Blood glucose, microalbuminuria, kidney index, total antioxidative capacity, laminin, advanced glycation end products (AGE), aldose reductase (AR) activity, and the relative quantity of transforming growth factor beta1 (TGF- beta1) mRNA were measured by different methods. The ultrastructural morphology was observed by transmission electron microscope. The physical behaviors of early DN rats were hypopraxia, cachexia, and polyuria, while those treated with high doses of BDL were vibrant and vigorous. For BDL-treated DN rats, when compared with vehicle-treated DN rats, the blood glucose level and the intensity of oxidative stress were ameliorated. Also, the microalbuminuria level, AGE either in serum or in renal, and AR activity were significantly reduced. Furthermore, the expression of TGF-beta1 mRNA in the kidney cortex was declined and the thickness of glomerular base membrane was decreased significantly. The ultrastructure of glomerulus and mesangial matrix of BDL-treated DN rats were ameliorated. BDL has protective effects on several pharmacological targets in the progress of DN and is a potential drug for the prevention of early DN.

Protective Effects of Astragalus Saponin I on Early Stage of Diabetic Nephropathy in Rats

Diabetic nephropathy (DN) has become the leading cause of end stage failure, but no renoprotective treatment has been very available for use in DN. Astragalus saponin I (AS I), a component extracted from Astragalus membranaceus BUNGE, was studied in experimental DN induced by administration of streptozotocin in male rats. The early DN rats were treated with 3 doses of AS I for 8 weeks to analyze its efficacy with different parameters. By comparison with vehicle-treated DN rats, the renal hypertrophy, the oxidative stress intensity, and the blood glucose level of DN rats were ameliorated by AS I. Also, the microalbuminuria level, advanced glycated end-products either in serum or in kidney cortex, and the aldose reductase activity were significantly reduced. Furthermore, the expression of transforming growth factor β1 mRNA in kidney cortex by RT-PCR analysis was markedly declined. Both the relative grade of mesangium hyperplasia by microscopical observation and the thickness of glomerular base membrane by electron microscope measurement were decreased significantly. Therefore, the results suggest that AS I has therapeutic effects on several pharmacological targets in the progress of DN and is a potential drug for prevention of early stage DN.