PURPOSE: Wound represents a major health challenge as they consume a large amount of healthcare resources to improve patient's quality of life. Many scientific studies have been conducted in search of ideal biomaterials with wound-healing activity for clinical use and collagen has been proven to be a suitable candidate biomaterial. This study intended to investigate the wound healing activity of collagen peptides derived from jellyfish following oral administration. METHODS: In this study, collagen was extracted from the jellyfish--Rhopilema esculentum using 1% pepsin. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and fourier transform infrared (FTIR) were used to identify and determine the molecular weight of the jellyfish collagen. Collagenase II, papain and alkaline proteinase were used to breakdown jellyfish collagen into collagen peptides. Wound scratch assay (in vitro) was done to determine migration potential of human umbilical vein endothelial cells (HUVEC) covering the artificial wound created on the cell monolayer following treatment with collagen peptides. In vivo studies were conducted to determine the effects of collagen peptides on wound healing by examining wound contraction, re-epithelialization, tissue regeneration and collagen deposition on the wounded skin of mice. Confidence level (p < 0.05) was considered significant using GraphPad Prism software. RESULTS: The yield of collagen was 4.31%. The SDS-PAGE and FTIR showed that extracted collagen from jellyfish was type I. Enzymatic hydrolysis of this collagen using collagenase II produced collagen peptides (CP) and hydrolysis with alkaline proteinase/papain resulted into collagen peptides (CP). Tricine SDS-PAGE revealed that collagen peptides consisted of protein fragments with molecular weight <25 kDa. Wound scratch assay showed that there were significant effects on the scratch closure on cells treated with collagen peptides at a concentration of 6.25 μg/mL for 48 h as compared to the vehicle treated cells. Overall treatment with collagen peptide on mice with full thickness excised wounds had a positive result in wound contraction as compared with the control. Histological assessment of peptides treated mice models showed remarkable sign of re-epithelialization, tissue regeneration and increased collagen deposition. Immunohistochemistry of the skin sections showed a significant increase in β-fibroblast growth factor (β-FGF) and the transforming growth factor-β (TGF-β) expression on collagen peptides treated group. CONCLUSION Collagen peptides derived from the jellyfish-Rhopilema esculentum can accelerate the wound healing process thus could be a therapeutic potential product that may be beneficial in wound clinics in the future.
Administration, Oral ; Animals ; Collagen ; administration & dosage ; isolation & purification ; metabolism ; pharmacology ; Fibroblast Growth Factors ; metabolism ; Human Umbilical Vein Endothelial Cells ; Humans ; Male ; Regeneration ; Scyphozoa ; chemistry ; Skin ; metabolism ; Skin Physiological Phenomena ; Stimulation, Chemical ; Transforming Growth Factor beta1 ; metabolism ; Wound Healing ; drug effects

To observe the effect of Tripterygium Glycosides Tablets on angiogenesis of rats with type Ⅱ collagen-induced arthritis( CIA) and on the tube formation of human umbilical vein endothelial cells( HUVEC) in vitro. The HUVEC were induced by 20 μg·L-1 vascular endothelial growth factor( VEGF) in vitro,and were treated with 0. 1,1,10 mg·L-1 Tripterygium Glycosides Tablets continuously for 7 hours. The numbers of branches of tube formation were measured. SD rats were immunized to establish CIA. CIA rats were treated with 9,18,36 mg·kg-1·d-1 Tripterygium Glycosides Tablets for 42 days. Histopathological examination( HE) was performed to observe the vascular morphology and vascular density in the synovial membrane of the inflamed joints. Immunohistochemistry and immunofluorescence were performed to observe the expression of platelets-endothelial cell adhesion molecule( CD31) and αsmooth muscle actin( αSMA) in synovial membrane. Immunohistochemistry and Western blot were performed to observe the expression of hypoxia-inducible factors 1α( HIF1α) and angiotensin 1( Ang1) in the synovial tissue. The results showed that the numbers of branches of tube formation of HUVEC induced by VEGF were improved,and declined significantly after treated by Tripterygium Glycosides Tablets. Compared with the normal group,the vascular density,CD31 positive expression,CD31 +/αSMA-immature and total vascular positive expression in the synovial membrane of the model group were significantly increased,and so as HIF1α and Ang1 in the synovium. Tripterygium Glycosides Tablets reduced the synovial vascular density and inhibited the positive expression of CD31,CD31+/αSMA-immature blood vessels and total vascular,but has no effect on CD31+/αSMA+mature blood vessels. Tripterygium Glycosides Tablets also inhibited the expression of HIF1α and Ang1 in synovial membrane of inflammatory joints. Our results demonstrated that Tripterygium Glycosides Tablets could inhibit the angiogenesis of synovial tissue in CIA rats and the tube formation of HUVEC,which is related to the down-regulation of HIF1α/Ang1 signal axis.
Angiogenesis Inhibitors ; pharmacology ; Angiotensin I ; metabolism ; Animals ; Arthritis, Experimental ; chemically induced ; drug therapy ; Drugs, Chinese Herbal ; pharmacology ; Glycosides ; pharmacology ; Human Umbilical Vein Endothelial Cells ; drug effects ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; metabolism ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; Synovial Membrane ; drug effects ; Tablets ; Tripterygium ; chemistry ; Vascular Endothelial Growth Factor A

BackgroundOxidized low-density lipoprotein (ox-LDL)-induced oxidative stress and endothelial apoptosis are essential for atherosclerosis. Our previous study has shown that ox-LDL-induced apoptosis is mediated by the protein kinase RNA-like endoplasmic reticulum kinase (PERK)/eukaryotic translation initiation factor 2α-subunit (eIF2α)/CCAAT/enhancer-binding protein homologous protein (CHOP) endoplasmic reticulum (ER) stress pathway in endothelial cells. Statins are cholesterol-lowering drugs that exert pleiotropic effects including suppression of oxidative stress. This study aimed to explore the roles of simvastatin on ox-LDL-induced ER stress and apoptosis in endothelial cells.

MethodsHuman umbilical vein endothelial cells (HUVECs) were treated with simvastatin (0.1, 0.5, or 2.5 μmol/L) or DEVD-CHO (selective inhibitor of caspase-3, 100 μmol/L) for 1 h before the addition of ox-LDL (100 μg/ml) and then incubated for 24 h, and untreated cells were used as a control group. Apoptosis, expression of PERK, phosphorylation of eIF2α, CHOP mRNA level, and caspase-3 activity were measured. Comparisons among multiple groups were performed with one-way analysis of variance (ANOVA) followed by post hoc pairwise comparisons using Tukey's tests. A value of P < 0.05 was considered statistically significant.

ResultsExposure of HUVECs to ox-LDL resulted in a significant increase in apoptosis (31.9% vs. 4.9%, P < 0.05). Simvastatin (0.1, 0.5, and 2.5 μmol/L) led to a suppression of ox-LDL-induced apoptosis (28.0%, 24.7%, and 13.8%, F = 15.039, all P < 0.05, compared with control group). Ox-LDL significantly increased the expression of PERK (499.5%, P < 0.05) and phosphorylation of eIF2α (451.6%, P < 0.05), if both of which in the control groups were considered as 100%. Simvastatin treatment (0.1, 0.5, and 2.5 μmol/L) blunted ox-LDL-induced expression of PERK (407.8%, 339.1%, and 187.5%, F = 10.121, all P < 0.05, compared with control group) and phosphorylation of eIF2α (407.8%, 339.1%, 187.5%, F = 11.430, all P < 0.05, compared with control group). In contrast, DEVD-CHO treatment had no significant effect on ox-LDL-induced expression of PERK (486.4%) and phosphorylation of eIF2α (418.8%). Exposure of HUVECs to ox-LDL also markedly induced caspase-3 activity together with increased CHOP mRNA level; these effects were inhibited by simvastatin treatment.

ConclusionsThis study suggested that simvastatin could inhibit ox-LDL-induced ER stress and apoptosis in vascular endothelial cells.

Apoptosis ; drug effects ; Cells, Cultured ; Endoplasmic Reticulum Stress ; drug effects ; Human Umbilical Vein Endothelial Cells ; drug effects ; metabolism ; Humans ; Lipoproteins, LDL ; pharmacology ; Oligopeptides ; pharmacology ; Simvastatin ; pharmacology

Angiogenesis is a crucial process in the development of inflammatory diseases, including cancer, psoriasis and rheumatoid arthritis. Recently, several alkaloids from Picrasma quassioides had been screened for angiogenic activity in the zebrafish model, and the results indicated that 1-methoxycarbony-β-carboline (MCC) could effectively inhibit blood vessel formation. In this study, we further confirmed that MCC can inhibit, in a concentration-dependent manner, the viability, migration, invasion, and tube formation of human umbilical vein endothelial cells (HUVECs) in vitro, as well as the regenerative vascular outgrowth of zebrafish caudal fin in vivo. In the zebrafish xenograft assay, MCC inhibited the growth of tumor masses and the metastatic transplanted DU145 tumor cells. The proteome profile array of the MCC-treated HUVECs showed that MCC could down-regulate several angiogenesis-related self-secreted proteins, including ANG, EGF, bFGF, GRO, IGF-1, PLG and MMP-1. In addition, the expression of two key membrane receptor proteins in angiogenesis, TIE-2 and uPAR, were also down-regulated after MCC treatment. Taken together, these results shed light on the potential therapeutic application of MCC as a potent natural angiogenesis inhibitor via multiple molecular targets.
Angiogenesis Inhibitors ; chemistry ; pharmacology ; Animals ; Carbolines ; chemistry ; pharmacology ; Cell Movement ; drug effects ; Cell Proliferation ; drug effects ; Epidermal Growth Factor ; genetics ; metabolism ; Fibroblast Growth Factors ; genetics ; metabolism ; Human Umbilical Vein Endothelial Cells ; cytology ; drug effects ; metabolism ; Humans ; Insulin-Like Growth Factor I ; genetics ; metabolism ; Neovascularization, Physiologic ; drug effects ; Picrasma ; chemistry ; Plant Extracts ; chemistry ; pharmacology ; Receptor, TIE-2 ; genetics ; metabolism ; Zebrafish ; embryology

To determine the effect of andrographolide (Andro) on angiogenesis of human umbilical vein endothelial cells (HUVECs).
 Methods: HUVECs were treated with different concentrations of Andro and the cell viability was detected with Cell Counting Kit-8 (CCK-8). HUVECs were treated with half lethal dose (IC50) of Andro. Matrigel was used to make capillary formation of HUVECs and the effect of Andro on capillary formation was evaluated by calculating the percentage of capillary formation. Moreover, the effects of Andro and the supernatant from cultured A549 tumor cells on capillary formation were evaluated by calculating the percentage of capillary formation. The effect of Andro on the expression of matrix metalloproteinase-9 (MMP-9) was determined with Western blot.
 Results: The cell viability of HUVECs decreased with the increase of Andro concentrations. IC50 was 20 μmol/L. The capillary formation of HUVECs was inhibited when treated with 20 μmol/L Andro for 24 hours. Moreover, Andro was able to antagonize the promotion of the capillary formation induced by the supernatant from cultured tumor cells. Andro could suppress the expression of MMP-9 and antagonize the capillary formation.
 Conclusion: Andro inhibits the capillary formation of HUVECs and can antagonize the promotion of angiogenesis induced by the supernatant from cultured tumor cells.
Capillaries ; drug effects ; Cell Survival ; Collagen ; Culture Media ; Diterpenes ; pharmacology ; Drug Combinations ; Human Umbilical Vein Endothelial Cells ; drug effects ; Humans ; Laminin ; Matrix Metalloproteinase 9 ; metabolism ; Neovascularization, Pathologic ; enzymology ; etiology ; prevention & control ; Proteoglycans ; Tumor Cells, Cultured

This study aimed to investigate the effect and mechanism of ophiopogonin D (OP-D) on Ang Ⅱ-induced HUVECs apoptosis, in order to provide a reliable basis for the safety and efficacy of traditional Chinese medicines. The effect of Ang Ⅱ on survival and total proteins content of HUVECs were measured by MTT and Western blotting. The effect of OP-D on Ang Ⅱ-induced lactate dehydrogenase (LDH) release rate in HUVECs was measured by enzyme standard instrument. The effects of OP-D and 11,12-EET on phosphorylation of JNK/c-Jun induced by Ang Ⅱ were measured by Western blot and RT-PCR with the help of JNK specific inhibitor SP600125 and CYP450 isozymes selective inhibitor 6-(2-propargyloxyphenyl) hexanoic acid (PPOH). The cell apoptosis was assayed by flow cytometry. According to the results, different doses of Ang Ⅱ had no significant effect on cell survival; treatment with Ang Ⅱ at 1×10⁻⁶ mol·L⁻¹ could increase the release of LDH (<0.001), improve the JNK and c-Jun phosphorylation levels(<0.01, <0.001), increase the expression of caspase-3(<0.01), and promote the apoptosis of HUVECs(<0.001). The phosphorylation of JNK and c-Jun could be inhibited by the pre-treatment with SP600125, 11,12-EET and OP-D. Pre-treatment with OP-D could significantly reduce the release of LDH induced by Ang Ⅱ stimulation, decrease the expression of caspase-3, and diminish the apoptosis of cells. The protective effect of OP-D was suppressed, when being pretreated with PPOH. The experimental results showed that the apoptosis of HUVECs induced by Ang Ⅱ may be associated with JNK/c-Jun signaling pathway. OP-D-mediated CYP2J2 expression increased 11,12-EET levels, and could remarkably resist Ang Ⅱ-induced injury and apoptosis of cells, which is associated with the maintenance of endothelium homeostasis.
Angiotensin II ; Apoptosis ; Arachidonic Acids ; metabolism ; Cells, Cultured ; Cytochrome P-450 Enzyme System ; metabolism ; Human Umbilical Vein Endothelial Cells ; cytology ; drug effects ; Humans ; Phosphorylation ; Saponins ; pharmacology ; Signal Transduction ; Spirostans ; pharmacology

OBJECTIVES: To investigate the effects of Astragaloside IV (AST) on diastolic function of rat thoracic aorta rings which was injured by microvesicles derived from hypoxia/reoxygenation (H/R)-treated human umbilical vein endothelial cells (HUVECs), and the mechanism of AST. METHODS: H/R-induced endothelial microvesicles (H/R-EMVs) were generated from cultured HUVECs under the condition of hypoxia for 12 hour/Reoxygenation for 4 hour, H/R-EMVs were stored in D-Hank's solution. Male Wistar rats were underwent thoracotomy, the thoracic aorta with intact endothelium were carefully removed and cut into 3~4 mm rings. The experiment was divided into six groups. H/R-EMVs group:thoracic aortic rings of rats were incubated in culture medium and treated with H/R-EMVs in a final concentration of 10g/ml; different doses of AST groups:thoracic aortic rings of rats were treated with 10, 20, 40, 60 mg/L AST co-incubated with 10g/ml H/R-EMVs respectively; control group were treated with the same volume of D-Hank's solution. Duration of incubation was 4 h, each group was tested in five replicate aortic rings. Effects of AST on endothelium-dependent relaxation were detected. The production of nitric oxide (NO) and the level of endothelial NO synthase (eNOS), phosphorylated eNOS (p-eNOS, Ser-1177), serine/threonine kinase (Akt), phosphorylated Akt (p-Akt, Ser-473), extracellular regulated protein kinases (ERK1/2) and phosphorylated ERK1/2 (p-ERK1/2, Thr202/Tyr204) of rat thoracic aortic rings were detected. RESULTS: Teng/ml H/R-EMVs could impaire the relaxation of rat thoracic aortic rings significantly (<0.01). Compared with H/R-EMVs group, relaxation of rat thoracic aortic rings was increased by 20, 40 and 60 mg/L AST in a concentration-dependent manner (<0.01), the level of NO production was also enhanced (<0.05, <0.01). The level of t-eNOS, t-Akt and ERK1/2 was not changed, but the level of p-eNOS, p-Akt and p-ERK1/2 increased by the treatment with AST (<0.01). CONCLUSIONS AST could effectively ameliorate endotheliumdependent relaxation of rat thoracic aortic rings impaired by H/R-EMVs in a concentration-dependent manner, the mechanism might involve the increase in production of NO, and the protein level of p-eNOS, p-Akt and p-ERK1/2.
Animals ; Aorta, Thoracic ; drug effects ; Cell-Derived Microparticles ; pathology ; Human Umbilical Vein Endothelial Cells ; Humans ; In Vitro Techniques ; MAP Kinase Signaling System ; Male ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase Type III ; metabolism ; Proto-Oncogene Proteins c-akt ; metabolism ; Rats ; Rats, Wistar ; Saponins ; pharmacology ; Triterpenes ; pharmacology ; Vasodilation

The aim of this paper was to observe the effect of gambogenic acid on angiogenesis of lung cancer and its preliminary mechanism. After culturing lung adenocarcinoma A549 cells, the conditioned medium was treated with gambogenic acid and then used to culture human umbilical vein endothelial cells (HUVECs) to establish the indirect contact cell co-culture system. A two-dimensional culture model of HUVEC was established with matrigel to observe the effect of gambogenic acid on angiogenesis. DAPI staining was used to observe the morphological changes in HUVEC cells after treatment with gambogenic acid under the fluorescence microscope. Annexin V-FITC/PI staining and flow cytometry analysis were used to determine gambogenic acid's effect on HUVEC cell apoptosis rate. The protein expressions of PI3K, p-PI3K, Akt, p-Akt were measured by Western blot. PTEN-siRNA was transfected into cells, and RT-PCR was used to detect the expression levels of PI3K and Akt genes. Gambogenic acid can significantly inhibit angiogenesis, and its inhibitory effect was dose-dependent. DAPI staining showed apoptotic morphological features of HUVEC cells under fluorescence microscope. Annexin V-FITC/PI staining showed that gambogenic acid induced apoptosis in HUVECs. The results of Western blot showed that the expressions of p-PI3K and p-Akt protein were down-regulated with gambogenic acid, while the expressions of PI3K and Akt protein was insignificant. The results of RT-PCR indicated that the expressions of PI3K and Akt protein were up-regulated by PTEN siRNA. Gambogenic acid can inhibit angiogenesis in lung cancer in vitro, and the mechanism of inhibiting angiogenesis may be related to the PI3K/Akt signaling pathway.
A549 Cells ; Apoptosis ; Coculture Techniques ; Human Umbilical Vein Endothelial Cells ; drug effects ; Humans ; Lung Neoplasms ; drug therapy ; pathology ; Neovascularization, Pathologic ; pathology ; PTEN Phosphohydrolase ; genetics ; Phosphatidylinositol 3-Kinases ; metabolism ; Proto-Oncogene Proteins c-akt ; metabolism ; Transfection ; Xanthenes ; pharmacology

OBJECTIVETo investigate the effects of polyunsaturated fatty acids (PUFA) ω-3 and ω-6, and their middle metabolites PGE2 and PGE3 on angiogenesis formation of gastric cancer, and to explore associated mechanism.

METHODSThe effects of ω-3, ω-6, PGE2, PGE3 on the proliferation and migration of human umbilical vein endothelial cell (HUVEC) were measured by proliferation and migration assay respectively. The angiogenesis assay in vivo was used to measure the effects of ω-3, ω-6, PGE2 and PGE3 on neovascularization. In all the assays, groups without ω-3, ω-6, PGE2 and PGE3 were designed as the control.

RESULTSWith the increased concentration of ω-6 from 1 μmol/L to 10 μmol/L, the proliferation ability of HUVECs enhanced, and the number of migration cells also increased from 28.2±3.0 to 32.8±2.1, which was higher than control group (21.2±3.2) respectively (both P<0.05). With the increased concentration of ω-3 from 1 μmol/L to 10 μmol/L, the proliferation ability of HUVECs was inhibited, and the number of migration cells decreased from 15.8±2.0 to 11.0±2.1, which was lower than control group (22.1±3.0) respectively (both P<0.05). In the angiogenesis assay, compared with control group (standard number: 43 721±4 654), the angiogenesis ability of HUVECs was significantly enhanced by ω-6 in concentration-dependent manner (1 μmol/L group: 63 238±4 795, 10 μmol/L group: 78 166±6 123, all P<0.01). Meanwhile, with the increased concentration of ω-3 from 1 μmol/L to 10 μmol/L, the angiogenesis ability was significantly decreased from 30 129±3 102 to 20 012±1 541(all P<0.01). The proliferation and migration ability of HUVECs were significantly promoted by ω-6 metabolites PGE2 (P<0.05) in a concentration-dependent manner. In contrast, ω-3 metabolites PGE3 significantly inhibited the proliferation and migration ability of HUVECs in a concentration-dependent manner (all P<0.05). After rofecoxib (a COX-2 specific inhibitor) inhibited the expression of COX-2, the expression level of PGE2 was significantly decreased in a dose-dependent manner. In co-culture system, whose gastric cancer cells expressed positive COX-2, ω-6 could increase angiogenesis of gastric cancer cells(P<0.01), but ω-3 could inhibit such angiogenesis(P<0.01). In co-culture system, whose gastric cancer cells did not express COX-2, ω-3 could inhibit the angiogenesis of gastric cancer cells (P<0.05), but ω-6 had no effect on angiogenesis.

CONCLUSIONSThe PUFA ω-6 can enhance the angiogenesis via the promotion of proliferation and migration of HUVECs, and COX-2 and PGE2 may play an important role in this process, whereas, the ω-3 can inhibit the angiogenesis through its middle metabolites PGE3 to inhibit the proliferation and migration of HUVECs. Results of this experiment may provide a new approach to inhibit and prevent the spread of gastric cancer.

Alprostadil ; analogs & derivatives ; pharmacology ; Angiogenesis Inducing Agents ; metabolism ; pharmacology ; Angiogenesis Inhibitors ; pharmacology ; Cell Count ; methods ; Cell Line, Tumor ; drug effects ; physiology ; Cell Migration Assays ; Cell Movement ; drug effects ; Cell Proliferation ; drug effects ; Coculture Techniques ; Cyclooxygenase 2 ; pharmacology ; Dinoprostone ; metabolism ; pharmacology ; Fatty Acids, Omega-3 ; pharmacology ; Fatty Acids, Omega-6 ; metabolism ; pharmacology ; Fatty Acids, Unsaturated ; pharmacology ; Human Umbilical Vein Endothelial Cells ; drug effects ; physiology ; Humans ; Lactones ; pharmacology ; Neovascularization, Pathologic ; physiopathology ; Stomach Neoplasms ; physiopathology ; Sulfones ; pharmacology

Angiotensin II (Ang II) is involved in endothelium injury during the development of hypertension. Tribulus terrestris (TT) is used to treat hypertension, arteriosclerosis, and post-stroke syndrome in China. The present study aimed to determine the effects of aqueous TT extracts on endothelial injury in spontaneously hypertensive rats (SHRs) and its protective effects against Ang II-induced injury in human umbilical vein endothelial cells (HUVECs). SHRs were administered intragastrically with TT (17.2 or 8.6 g·kg·d) for 6 weeks, using valsartan (13.5 mg·kg·d) as positive control. Blood pressure, heart rate, endothelial morphology of the thoracic aorta, serum levels of Ang II, endothelin-1 (ET-1), superoxide dismutase (SOD) and malonaldehyde (MDA) were measured. The endothelial injury of HUVECs was induced by 2 × 10 mol·L Ang II. Cell Apoptosisapoptosis, intracellular reactive oxygen species (ROS) was assessed. Endothelial nitric oxide synthase (eNOS), ET-1, SOD, and MDA in the cell culture supernatant and cell migration were assayed. The expression of hypertension-linked genes and proteins were analyzed. TT decreased systolic pressure, diastolic pressure, mean arterial pressure and heart rate, improved endothelial integrity of thoracic aorta, and decreased serum leptin, Ang II, ET-1, NPY, and Hcy, while increased NO in SHRs. TT suppressed Ang II-induced HUVEC proliferation and apoptosis and prolonged the survival, and increased cell migration. TT regulated the ROS, and decreased mRNA expression of Akt1, JAK2, PI3Kα, Erk2, FAK, and NF-κB p65 and protein expression of Erk2, FAK, and NF-κB p65. In conclusion, TT demonstrated anti-hypertensive and endothelial protective effects by regulating Erk2, FAK and NF-κB p65.
Angiotensin II ; metabolism ; Animals ; Antihypertensive Agents ; administration & dosage ; Apoptosis ; drug effects ; Blood Pressure ; drug effects ; Endothelium, Vascular ; drug effects ; metabolism ; Human Umbilical Vein Endothelial Cells ; drug effects ; Humans ; Hypertension ; drug therapy ; genetics ; metabolism ; physiopathology ; Male ; NF-kappa B ; genetics ; metabolism ; Nitric Oxide Synthase Type III ; genetics ; metabolism ; Oxidative Stress ; drug effects ; Plant Extracts ; administration & dosage ; Proto-Oncogene Proteins c-akt ; genetics ; metabolism ; Rats ; Rats, Inbred SHR ; Rats, Inbred WKY ; Reactive Oxygen Species ; metabolism ; Tribulus ; chemistry