Grape seed proanthocyanidins protect against streptozotocin­induced diabetic nephropathy by attenuating endoplasmic reticulum stress­induced apoptosis.

Diabetic nephropathy (DN) is by far the most common cause of end­stage renal disease (ESRD) in industrial countries, accounting for ~45% of all new ESRD cases in the United States. Grape seed proanthocyanidin extracts (GSPE) are powerful antioxidants, with an antioxidant ability 50­fold greater than that of vitamin E and 20­fold greater than that of vitamin C. The present study investigated whether GSPE can protect against streptozotocin (STZ)­induced DN and aimed to elucidate a possible mechanism. Male Sprague Dawley rats were randomly divided into three groups: Control group (N), diabetes mellitus group (DM) injected with 40 mg/kg STZ, and the GSPE treatment group (intragastric administration of 250 mg/kg/day GSPE for 16 weeks after diabetes was induced in the rats). Blood and kidney samples were collected after treatment. The renal pathological changes were determined with periodic acid­Schiff (PAS) staining, while the protein expression levels of glucose­regulated protein 78 (GRP78), phosphorylated­extracellular signal­regulated kinase (p­ERK) and Caspase­12 were determined by western blotting and immunohistochemical staining. Apoptosis was determined with a terminal deoxynucleotidyl transferase dUTP nick­end labeling (TUNEL) assay. Compared with the DM group, the GSPE group had no significant changes in the blood urea nitrogen (BUN) level and serum creatinine (Scr) level, but showed a significant decline in the renal index (RI) level and 24­h urinary albumin level (P<0.05). The histopathology results indicated very little pathological damage in the GSPE group. Compared with the DM group, the GSPE group had a significantly reduced number of TUNEL­positive cells (P<0.05), and the GSPE group had an obvious reduction in the protein expression of GRP78, p­ERK, and Caspase­12 (P<0.05). In this study, the results indicated that GSPE can protect renal function and attenuate endoplasmic reticulum stress­induced apoptosis via the Caspase­12 pathway in STZ­induced DN.

Nephrin loss is reduced by grape seed proanthocyanidins in the experimental diabetic nephropathy rat model.

Diabetic nephropathy (DN) is one of the major causes of end­stage renal failure. Grape seed proanthocyanidin extracts (GSPE) are known to act as antioxidants. The current study aimed to determine the effects of GSPE on the streptozotocin (STZ)­induced diabetic rat model and to explore the underlying mechanism of its action. Wistar rats were induced into a diabetic state by injection of STZ and were treated with 250 mg·kg­1·day­1 GSPE for 24 weeks. Kidney samples were collected for observation of renal pathological changes by light microscope (periodic acid­Schiff staining) and electron microscopy. Reverse transcription­polymerase chain reaction, western blotting, and immunohistochemical staining were used to detect the mRNA and protein expression of the receptor for advanced glycation end­products (RAGE), nephrin and podocin. The results indicated that diabetic rats treated with GSPE had markedly reduced Ccr, urinary albumin excretion, ratio of kidney weight to body weight, AGEs and ECM accumulation (P<0.01) compared with that in the diabetic rats. GSPE treatment can also reverse the renal pathological damage in diabetic rats. Further results indicated that GSPE treatment significantly decreased the RAGE expression level (P<0.01), and significantly increased the expression level of nephrin in the kidney and glomeruli of diabetic rats (P<0.01). However, no significant differences were identified in the expression of podocin following GSPE treatment (P>0.05). In conclusion, the results demonstrated that GSPE exerts a reno­protective effect by decreasing urinary albumin excretion and reversing renal pathological damage in diabetic rats. The underlying mechanism of GSPE activity is associated with the decreased expression of the AGEs/RAGE axis and the increased expression of nephrin in diabetic rats.

Quantitative assessment of bioactive compounds and the antioxidant activity of 15 jujube cultivars.

Fifteen jujube cultivars late in their maturation were analysed in the red stage for bioactive compounds; including total phenolics (bound/free), total flavonoids, total polysaccharides, ascorbic acid, total triterpenes, proanthocyanidins and cyclic adenosine monophosphate (cAMP). The antioxidant activity was evaluated using the 2,2-diphenyl-1-picrylhydracyl (DPPH) and 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonicacid) (ABTS(+)) scavenging methods and the ferric reducing antioxidant power (FRAP) assay. The Order Performance by Similarity to Ideal Solution method (TOPSIS) was employed to evaluate the nutrition of different jujube cultivars based on their bioactive compounds. The results indicated that the contents of bioactive compounds and antioxidant capacities vary between different jujube cultivars. Correlation analysis revealed that ascorbic acid, polyphenols and proanthocyanidins were the 3 main components responsible for the antioxidant activity of jujubes. TOPSIS analysis indicated that Zyzyphus jujube cv. Nanjingyazao ranks the highest of the 15 jujube fruits with regards to nutritional value.

Grape seed proanthocyanidin extract protects from cisplatin-induced nephrotoxicity by inhibiting endoplasmic reticulum stress-induced apoptosis.

Cisplatin (CP) is used as an antineoplastic drug in the clinic, but its nephrotoxicity limits its use. Grape seed proanthocyanidin extract (GSPE) is a powerful antioxidant. In this study, we investigated whether GSPE can prevent CP-induced nephrotoxicity and explored the underlying mechanism. Male C57/BL6 mice were randomly divided into four groups: control group (N), CP group (C), receiving an intraperitoneal (ip) injection of 20 mg/kg CP, GSPE group (G), receiving an intragastric (ig) dose of 500 mg/kg GSPE, and CP+GSPE group (C+G), where ig administration of GSPE was performed 30 min prior to ip injection of CP, followed by an additional ig administration of GSPE 72 h later. Blood and kidney samples were collected 120 h after treatment. The pathological changes in the kidney were examined by periodic acid-Schiff (PAS) staining, while the protein levels of glucose-regulated protein 78 (GRP78), phosphorylated­extracellular signal-regulated kinase (p-ERK) and caspase-12 were examined by western blotting and immunohistochemical staining. Apoptosis was examined by a terminal deoxynucleotidyl transferase dUTP nick­end labeling (TUNEL) assay. Compared to the CP group, the CP+GSPE group had a significant decrease in the level of blood urea nitrogen (BUN), serum creatinine (Scr) and reduced renal index (RI) (P<0.05), and showed limited histopathological damage. The number of TUNEL-positive cells was significantly reduced in the CP+GSPE group compared to the CP group (P<0.05), and the protein expression of GRP78, p-ERK and caspase-12 was significantly reduced in the CP+GSPE group (P<0.05). We conclude that GSPE can protect the renal function from CP-induced nephrotoxicity and can attenuate the endoplasmic reticulum (ER) stress­induced apoptosis via regulation of the caspase-12 pathway.

Proteomics approach to study the mechanism of action of grape seed proanthocyanidin extracts on arterial remodeling in diabetic rats.

Arterial remodeling is the change in structural properties of vessel in diabetes mellitus and contributes to the development of vascular complications. To prevent this development and to improve diabetic vascular complications, effective therapies directed toward the key molecular target are required. Grape seed proanthocyanidin extracts (GSPE) have been reported to be effective in treating arteriosclerosis, while little is known about the functional protein changes. We used streptozocin to induce diabetic rats. GSPE (250 mg/kg body weight/day) were administrated to diabetic rats for 24 weeks. Consequently, 2-D difference gel electrophoresis and mass spectrometry were used to investigate aortic protein profiles among the control, untreated and GSPE- treated diabetic rats. The expression of 23 proteins was found either up-regulated or down-regulated in the aorta of untreated diabetic rats. Only the expression of 15 proteins was found either down-regulated or up-regulated in the aorta of GSPE- treated diabetic rats. Our findings might help to better understand the mechanism of diabetic macrovascular complications and provide novel targets for evaluating the effects of GSPE therapy.

Effects of grape seed proanthocyanidin extracts on aortic pulse wave velocity in streptozocin induced diabetic rats.

Grape seed proanthocyanidin extracts (GSPEs) have been reported to be effective in treating arteriosclerosis, while little is known about therapeutic agents against diabetic macrovascular complications. We used streptozocin to induce diabetic rats. GSPEs (250 mg/kg of body weight) were administrated to diabetic rats for 24 weeks. Aortic blood pressure and pulse wave velocity (PWV) were determined in anesthetized rats. Serum glycated hemoglobin and advanced glycation end products (AGEs) were determined. An electronic microscope was used to observe the changes in aortic ultrastructure. Immunohistochemistry was used to evaluate the receptor of advanced glycation end product (RAGE) protein expression in aortic tissue. GSPEs significantly decreased aortic PWV, blood pressure, and aortic medial thickness (P<0.05), and inhibited the migration of vascular smooth muscle cells. GSPEs significantly reduced the AGEs (P<0.05) and the expression of RAGE in aortas of diabetic rats. GSPEs play an important role against diabetic macrovascular complications. This study may provide a new recognition of natural medicine for the treatment of diabetic macrovascular complications.

Grape seed proanthocyanidins ameliorate diabetic nephropathy via modulation of levels of AGE, RAGE and CTGF.

BACKGROUND: Diabetic nephropathy (DN) is the most common cause of end-stage renal failure. Grape seed proanthocyanidin extracts (GSPE) are powerful antioxidants. However, the role of GSPE on advanced glycation end products (AGEs), receptor for advanced glycation end products (RAGE) and expression of connective tissue growth factor (CTGF) in DN has not been elucidated. Using streptozotocin-induced diabetic rats, we evaluated the effects of GSPE in DN. METHODS: Wistar rats were induced into diabetes using streptozotocin injections and diabetic rats were treated with GSPE (dosage: 500 mg x kg(-1) x day(-1)) for 24 weeks. The renal pathological changes were examined with PAS staining and electron microscope. The mRNA and protein expression of RAGE and CTGF in kidney were detected by RT-PCR, Western blot and immunohistochemical staining. RESULTS: Treated animals showed reduction in serum AGEs (p < 0.01), proteinuria (p < 0.01) and systolic blood pressure (p < 0.01). GSPE reduced the expression of RAGE (p < 0.01) and CTGF (p < 0.01) in the kidney, which were contributing to reversal of extracellular matrix accumulation in DN. CONCLUSION: Our results suggest that GSPE hold substantial promise for the treatment of DN. GSPE can decrease proteinuria, attenuating the progression of nephropathy in diabetic rats. Renoprotective effects of GSPE are correlated with suppression on AGEs/RAGE axis, downregulating expression of CTGF.

Effects of grape seed proanthocyanidins extracts on AGEs and expression of bone morphogenetic protein-7 in diabetic rats.

BACKGROUND: Diabetic nephropathy (DN) is the most common cause of end-stage renal failure. Grape seed proanthocyanidin extracts (GSPEs) are powerful antioxidants. However, the role of GSPEs in advanced glycation end products (AGEs), expression of connective tissue growth factor (CTGF) and bone morphogenetic protein-7 (BMP-7) in DN has not been elucidated. Using streptozotocin-induced diabetic rats, we evaluated the effects of GSPE in DN. METHODS: Wistar rats were induced into diabetes using streptozotocin injections, and diabetic rats were treated with GSPE (high dosage: 500 mg/kg per day; low dosage: 250 mg/kg.per day) for 24 weeks. The renal pathologic changes were examined with periodic acid-Schiff (PAS) staining under an electron microscope. The mRNA and protein expressions of CTGF and BMP-7 in kidney were detected by RT-PCR and immunohistochemical staining. RESULTS: Treated animals showed a reduction in serum AGEs (p<0.01), proteinuria (p<0.01) and systolic blood pressure (SBP) (p<0.01). GSPE reduced the expression of mRNA and protein of CTGF in the kidney (p<0.05 and p<0.01), which were contributing to reversal of extracellular matrix (ECM) accumulation in DN. GSPE increased the expression of mRNA and protein of BMP-7 in the kidney (p<0.05 and p<0.01), which were contributing to improvement of the microstructure of podocytes and ECM accumulation in DN. CONCLUSION: Our results suggest that GSPEs hold substantial promise for the treatment of DN. GSPEs can decrease proteinuria and attenuate the progression of nephropathy in diabetic rats. Renoprotective effects of GSPE correlated with suppression of AGEs, down-regulating expression of CTGF and up-regulating the expression of BMP-7.

Back-regulation of six oxidative stress proteins with grape seed proanthocyanidin extracts in rat diabetic nephropathy.

Diabetic nephropathy (DN) is a major cause of morbidity and mortality in diabetic patients. To prevent the development of this disease and to improve advanced kidney injury, effective therapies directed toward the key molecular target are required. Grape seed proanthocyanidin extracts (GSPE) have been reported to be effective in treating DN, while little is known about the functional protein changes. In this study, we used streptozotocin (STZ) to induce diabetic rats. GSPE (250 mg/kg body weight/day) were administrated to diabetic rats for 24 weeks. Serum glucose, glycated hemoglobin, and advanced glycation end products were determined. Consequently, 2-D difference gel electrophoresis and mass spectrometry were used to investigate kidney protein profiles among the control, untreated and GSPE treated diabetic rats. Twenty-five proteins were found either up-regulated or down-regulated in the kidneys of untreated diabetic rats. Only nine proteins in the kidneys of diabetic rats were found to be back-regulated to normal levels after GSPE therapy. These back-regulated proteins are involved in oxidative stress, glycosylation damage, and amino acids metabolism. Our findings might help to better understanding of the mechanism of DN, and provide novel targets for estimating the effects of GSPE therapy.

A novel approach of proteomics to study the mechanism of action of grape seed proanthocyanidin extracts on diabetic retinopathy in rats.

BACKGROUND: Diabetic retinopathy (DR) is a leading cause of visual impairment and blindness among the people of occupational age. To prevent the progress of retina injury, effective therapies directed toward the key molecular target are required. Grape seed proanthocyanidin extracts (GSPE) have been reported to be effective in treating diabetic complications, while little is discussed about the functional protein changes. METHODS: We used streptozotocin (STZ) to induce diabetes in rats. GSPE (250 mg/kg body weight per day) were administrated to diabetic rats for 24 weeks. Serum glucose, glycated hemoglobin and advanced glycation end products (AGEs) were determined. Consequently, 2-D difference gel electrophoresis and mass spectrometry were used to investigate retina protein profiles among control, STZ-induced diabetic rats, and GSPE treated diabetic rats. RESULTS: GSPE significantly reduced the AGEs of diabetic rats (P < 0.05). Moreover, GSPE significantly suppressed the vascular lesions of central regions, decreased capillary enlargements and neovascularization, similar to those of the control rats under light microscope. Eighteen proteins were found either up-regulated or down-regulated in the retina of STZ-induced diabetic rats. And seven proteins in the retina of diabetic rats were found to be back-regulated to normal levels after GSPE therapy. These back-regulated proteins are involved in many important biological processes such as heat shock, ubiquitin-proteasome system, cell proliferation, cell growth and glucose metabolism. CONCLUSIONS: These findings might promote a better understanding for the mechanism of DR, and provide novel targets for evaluating the effects of GSPE therapy.

Cardioprotective effects of grape seed proanthocyanidins extracts in streptozocin induced diabetic rats.

The aim of this study was to clarify whether grape seed proanthocyanidins extracts (GSPE) were therapeutic agents against diabetic cardiomyopathy. After diabetes was induced by STZ intravenously into the tail veins, GSPE (250 mg/kg body weight/d) were administrated for 24 weeks. Serum glucose, glycated hemoglobin (HbA1c), and advanced glycation end products (AGEs) were determined. Electronic microscopy was used to observe the changes of myocardial ultrastructure. Reverse transcription polymerase chain reaction (RT-PCR) was used to evaluate the receptor of advanced glycation end products (RAGE), nuclear factor-kappaB (NF-kappaB), and transforming growth factor-betal (TGF-betal) gene expression in myocardial tissue. GSPE significantly reduced the AGEs of diabetic rats (P < 0.05). After being treated by GSPE, the levels of RAGE, NF-kappaB, and TGF-beta1 mRNA transcription in the myocardial tissue of diabetic rats were reduced (P < 0.05), the number of degenerated mitochondria was decreased, and the preservation of the fine structure of the LV myocardium was improved. In conclusion, GSPE plays an important role against diabetic cardiomyopathy. With the decreasing of AGEs, it can ameliorate glycation-associated cardiac damage. This study may provide a new recognition of natural medicine for the treatment of diabetic cardiomyopathy.

[Experimental studies on antianimia effect of shengxuesu].

OBJECTIVE: Using animal anemia models to observe the antianemia effect of Shengxuesu, and to afford an experimental basis for preventing and treating anemia. METHOD: Rat model of iron deficiency induced by denutrition and mouse model of nemorrhagic anemia by blood lefting were established. Indices of hemoglobin(HB), red blood cell count(RBC), hematocrit(HCT), mean corpuscular hemoglobin count(MCHC), serum iron(SI), serum ferritin (SF) and total iron-binding capacity(TIBC) were monitored. RESULT: A dosage of Shengxuesu 0.5-2 g.kg-1 was given to the rat model of hypoferric anemia by gavage for 15 days, and to the mouse model of hemorrhagic anemia by gavage for 7 days. The result shows that HB, RBC, HCT, MCHC in blood and iron, ferroprotein in serum were elevated significantly; but total bounding iron in serum was decreased. Meanwhile, diet amount, diet consumption and general activity of the model rats were increased.