The purpose of study was to investigate the effects of L-arginine and cilostazol on platelet-activation and aggregation reserve in vitro, so as to provide proof for selecting reversible activation-inhibitors for platelets lyophilization. Activation and function of platelets were investigated by using flow cytometry with the CD62p and PAC-1 expression and re-expression after being activated by thrombin, and by means of platelet aggregation reaction to thrombin, ADP and propyl gallate, as well as coagulation activity of platelets. The results showed that expression of CD62p and PAC-1 increased after being pretreated. Both L-arginie and cilostazol could inhibit CD62p and PAC-1 expression and related with their concentrations. Cilostazol had an intensive inhibition effect on expressions of CD62p and PAC-1 induced by thrombin, and the inhibition increased when concentration augmented. L-arginine had the same effects on PAC-1, but had no effects on CD62p. L-arginine and cilostazol inhibited aggregation induced by thrombin, ADP and propyl gallate, and the inhibitions were related directly with dosage. When L-arginine concentration was higher or equal to 15 mmol/L, or cilostazol concentration was in range of 1 - 4 mmol/L, the aggregation time were prolonged so much or even no aggregation. It is concluded that when L-Arginine concentration is 5 mmol/L and 10 mmol/L, platelet activation can be inhibited, but aggregation ability and characters keep intact. Concentration at 5 mmol/L may be the best. 1 mmol/L of cilostazol can inhibit activation in vitro and retain part of platelet ability of aggregation and reexpression.
Arginine ; pharmacology ; Blood Platelets ; metabolism ; Humans ; P-Selectin ; drug effects ; metabolism ; Platelet Activation ; drug effects ; Platelet Aggregation ; drug effects ; Platelet Aggregation Inhibitors ; pharmacology ; Tetrazoles ; pharmacology

Angiotensin II Type 1 Receptor Blockers ; pharmacology ; Animals ; Cell Proliferation ; drug effects ; Cells, Cultured ; Collagen Type I ; biosynthesis ; Hepatocytes ; cytology ; metabolism ; Tetrazoles ; pharmacology ; Valine ; analogs & derivatives ; pharmacology ; Valsartan

OBJECTIVETo explore the effect of irbesartan on angiotensin-converting enzyme 2 (ACE2) mRNA expression in diabetic rat myocardium.

METHODSThirty 8-week-old male Wistar rats were randomly divided into control group (n=7), diabetic model group (n=14) and irbesartan group (n=9). Diabetes was induced by a single intraperitoneal injection of STZ (55 mg/kg), a blood glucose>16.7 mmol/L 72 h after the injection indicated successful establishment of diabetes. Four weeks after the modeling, the rats in irbesartan group were given 50 mg/kg irbesartan. ELISA was used to measure myocardial AngII content in the rats, and myocardial ACE2 mRNA expression was determined by real-time PCR.

RESULTSMyocardial AngII level in the diabetic model group was significantly higher than that in the control group (P<0.001). Irbesartan administration significantly lowered cardiac AngII levels in the diabetic rats (P<0.001). The rats in irbesartan group showed significantly increased myocardial ACE2 mRNA expression compared with those in the control and diabetic rat groups (P<0.05).

CONCLUSIONIrbesartan can increase ACE2 mRNA expression in the myocardium, which might be one of the mechanisms underlying its effect in improving the cardiac function in diabetic rats.

Animals ; Biphenyl Compounds ; pharmacology ; Diabetes Mellitus, Experimental ; enzymology ; Male ; Myocardium ; enzymology ; Peptidyl-Dipeptidase A ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Random Allocation ; Rats ; Rats, Wistar ; Tetrazoles ; pharmacology

OBJECTIVETo evaluate the effect of irbesartan on the proliferation, apoptosis, and VEGF mRNA expression of human umbilical vein cell line EA.hy926 in vitro.

METHODSThe human umbilical vein cell line EA.hyY926 were treated with various concentrations of irbesartan for 24 h. The cell proliferation after the treatment was detected by CCK8 assay, flow cytometry and FITC Annexin V/PI kit were used to detect changes in the cell apoptosis. RT-PCR was used to evaluate the expression of VEGF mRNA.

RESULTSThere were no changes in cell shape with various concentration of irbesartan. CCK-8 assay showed a greater rate of the cell proliferation in irbesartan group than that in control group with a dose-independent manner after 24 h treatment. After incubation with irbesartan, cell proliferation rate was significant (P < 0.05). FCM analysis showed no significantly changes in the cell apoptosis. Irbesartan increased the proliferation of EA.hy926 cells. At concentration of 1 x 10(-4), 1 x 10(-5), 1 x 10(-6) mol/L, VEGF mRNA expression enhanced either (P < 0.05).

CONCLUSIONIrbesartan could promote the proliferation and up-regulated VEGFmRNA expression in EA.hy926 cell line. This result suggested that in addition to antihypertensive effect, angiotensin receptor antagonist might be a novel therapeutic approach to chronic ischemic heart disease as heart failure.

Apoptosis ; drug effects ; Biphenyl Compounds ; pharmacology ; Cell Line ; Cell Proliferation ; drug effects ; Humans ; RNA, Messenger ; genetics ; Tetrazoles ; pharmacology ; Umbilical Veins ; cytology ; metabolism ; Vascular Endothelial Growth Factor A ; metabolism

BACKGROUNDVascular smooth muscle cell proliferation is an important process in the development of atherosclerosis and is associated with other cellular processes in atherogenesis. Telmisartan is reported to have partial peroxisome proliferator-activated receptor (PPAR)-γ activating properties and has been referred to as selective PPAR modulators, but valsartan just blocks angiotensin II (AngII) type 1 (AT1) receptors. This study aimed to compare the different effects of telmisartan and valsartan on human aortic smooth muscle cells (HASMCs) proliferation.

METHODSAbility of telmisartan and valsartan to inhibit proliferation of HASMCs was evaluated by the Cell Counting Kit-8 (CCK-8) in continuous cell culture. Whether the antiproliferative effects of telmisartan and valsartan depend on their effects on AngII receptors or activating the peroxisome PPAR-γ was also investigated in this study.

RESULTSTelmisartan inhibited proliferation of HASMCs by 52.4% (P < 0.01) at the concentration of 25 µmol/L and the effect depended on the dose of telmisartan, but valsartan had little effect on HASMCs proliferation (P > 0.05) and no dose response. When tested in cells stimulated with AngII, telmisartan had the same inhibition of HASMCs by 59.2% (P < 0.05) and valsartan also inhibited it by 41.6% (P < 0.05). Telmisartan and valsartan had the same effect on down-regulating AT1 receptor expression and telmisartan was superior to valsartan up-regulating AngII type 2 (AT2) receptor expression. Antiproliferative effects of telmisartan were observed when HASMCs were treated with the PPAR-γ antagonist GW9662 but antiproliferative effects of the PPAR-γ activator pioglitazone were not observed.

CONCLUSIONSTelmisartan, but not valsartan, inhibits HASMCs proliferation and has dose-dependent response without stimulation of AngII. AT2 receptor up-regulation of telmisartan contributes to its greater antiproliferative effects than valsartan. Its PPAR-γ activation does not play a critical role in inhibiting HASMCs proliferation.

Benzimidazoles ; pharmacology ; Benzoates ; pharmacology ; Cell Proliferation ; drug effects ; Humans ; Muscle, Smooth, Vascular ; cytology ; metabolism ; Myocytes, Smooth Muscle ; cytology ; drug effects ; PPAR gamma ; metabolism ; Receptor, Angiotensin, Type 1 ; metabolism ; Receptor, Angiotensin, Type 2 ; metabolism ; Tetrazoles ; pharmacology ; Valine ; analogs & derivatives ; pharmacology ; Valsartan

OBJECTIVETo explore the association between renal transforming growth factor-β1 (TGF-β1) and the expressions of α3 and β1 integrins and observe the effect of irbesartan on their expressions in diabetic rats.

METHODSThirty 8-week-old male Wistar rats were randomly divided into normal control group (n=7), diabetic control group (n=14) and irbesartan group (n=9). Rat models of diabetes were established by a single peritoneal injection of streptozotocin (STZ), and 4 weeks later the rats received irbesartan treatment for 8 weeks. Enzyme-linked immunosorbent assay (ELISA) was used to measure the urinary albumin excretion rate, and PAS staining was utilized to observe the renal pathologies. Immunohistochemistry was performed for semi-quantitative determination of podocyte density, and real-time RT-PCR was used to detect the renal TGF-β1 and α3/β1 integrin mRNA expressions.

RESULTSIn diabetic rats, the expression of renal TGF-β1 mRNA was significantly increased, while α3 and β1 integrin mRNA expressions and podocyte density significantly decreased with increased proteinuria. Irbesartan obviously improved such changes.

CONCLUSIONIn diabetic rats renal TGF-β1 can regulate α3 and β1 integrin mRNA expressions to reduce the number of podocytes, and inhibition of this pathway may be one of the mechanisms of the renal protective effect of irbesartan.

Animals ; Biphenyl Compounds ; pharmacology ; Diabetes Mellitus ; metabolism ; Diabetic Nephropathies ; metabolism ; Integrin alpha3 ; metabolism ; Integrin beta1 ; metabolism ; Kidney ; drug effects ; metabolism ; Male ; Rats ; Rats, Wistar ; Tetrazoles ; pharmacology ; Transforming Growth Factor beta1 ; metabolism

OBJECTIVETo observe the effect of Tripterygium glycosides (TG) on the expression of hypoxia-inducible factor-1α and endothelin-1 in the kidney of diabetic rats and explore the possible mechanism underlying the protective effect of TG against diabetic nephropathy.

METHODSSixty 8-week-old male SD rats were randomly divided into normal control group (n=10) and streptozotocin-induced diabetes mellitus (DM) model group (n=50). The diabetic model rats were then randomly divided into DM group, low-dose (8 mg/kg) and high-dose (16 mg/kg) TG treatment groups, and Irbesartan (50 mg/kg) treatment group. After 8 weeks, the levels of blood glucose (BG), 24-h urine protein (24 h Upro), serum creatinine (Scr) and blood urea nitrogen (BUN) were measured. The pathological changes in the renal tissues were examined by optical microscopy, and the mean glomerular area (MGA) and mean glomerular volume (MGV) were measured with pathological image analysis. Immunohistochemical and Western blotting were used to detect the expression of HIF-1α and ET-1 protein in the renal tissue, and their mRNA expressions were detected using real-time fluorescence quantitative PCR.

RESULTSHIF-1α and ET-1 expression increased in the kidney of diabetic rats. Compared with the diabetic model rats, the rats receiving TG and Irbesartan treatment showed decreased levels of Scr, BUN, 24h Upro, MGA and MGV, improved renal histopathology, and reduced expression of HIF-1α and ET-1 mRNA and protein in the renal tissue. These changes were more obvious in high-dose TG treatment group. Correlation analysis showed that the expression of HIF-1α was positively correlated with that of ET-1, and they were both positively correlated with kidney weight index (KW/BW), 24 h Upro, MGA, and MGV.

CONCLUSIONHIF-1α and ET-1 are overexpressed in the kidney of diabetic rats. TG can improve kidney damage in diabetic rats and delay the development of diabetic nephropathy by inhibiting the HIF-1α and ET-1 expression.

Animals ; Biphenyl Compounds ; pharmacology ; Blood Glucose ; Blood Urea Nitrogen ; Creatinine ; blood ; Diabetes Mellitus, Experimental ; metabolism ; Endothelin-1 ; metabolism ; Glycosides ; pharmacology ; Hypoxia-Inducible Factor 1, alpha Subunit ; metabolism ; Kidney ; drug effects ; metabolism ; Male ; Rats ; Rats, Sprague-Dawley ; Tetrazoles ; pharmacology ; Tripterygium ; chemistry

OBJECTIVETo investigate the role of Toll-like receptor 4 (TLR4) signaling pathway in the activation of rennin- angiotensin system (RAS) in adipose cells.

METHODS3T3-L1 cells induced with isobutylmethylxanthine, insulin and dexamethasone to differentiate into adipocytes were stimulated by LPS with or without irbesartan pretreatment. The expression levels of TLR4, angiotensinogen (AGT) and angiotensin II receptor type 1 (ATlR) mRNA in 3T3-L1 cells was determined by RT-PCR, and their protein expressions were detected with Western-blotting. Immunofluorescence double staining was used to observe the translocation of NF-κB p65 subunit in the cells.

RESULTSStimulation with LPS dose- and time-dependently increased the mRNA and protein expressions of TLR4, AGT and AT1R. LPS exposure resulted in enhanced translocation of NF-κB p65 subunit in the adipose cells, which was attenuated by irbesartan pretreatment.

CONCLUSIONActivation of TLR4 signaling pathway may trigger the activation of local RAS in adipose cells.

3T3-L1 Cells ; Adipocytes ; metabolism ; Angiotensinogen ; metabolism ; Animals ; Biphenyl Compounds ; pharmacology ; Mice ; RNA, Messenger ; Receptor, Angiotensin, Type 1 ; metabolism ; Renin-Angiotensin System ; Signal Transduction ; Tetrazoles ; pharmacology ; Toll-Like Receptor 4 ; metabolism ; Transcription Factor RelA ; metabolism

OBJECTIVE: To investigate cardiotrophin-1(CT-1) expression in the ventricle and the effects of angiotensin II type I receptor antagonist (AT(1)RA) irbesartan on the ventricular remodeling in adriamycin myocardiopathy. METHODS: Thirty male SD rats were randomized into 2 groups: a control group (n=10) and a model group (n=20). The model group was administered adriamycin and 18 rats survived. And theses rats were randomized again into 2 groups. One was treated with irbesartan [50 mg/(kg x d), with stomach-tube], and the other received equal saline, so did the control group. After 12 weeks, the protein level of CT-1 was detected by immunohistochemistry. RESULTS: Ventricular CT-1 in the model control group and the treatment group was higher than that in the control group and the correlation analysis showed that ventricular CT-1 of the model control group was positively correlated with the left ventricular weight index, and CT-1 of the treatment group was lower than that of the model control group. CONCLUSION CT-1 was assumed to take part in the ventricular remodeling. The mechanism of irbesartan on the ventricular remodeling may be related to the downregulation of CT-1 expression.
Angiotensin II Type 1 Receptor Blockers ; pharmacology ; Animals ; Biphenyl Compounds ; pharmacology ; Cardiomyopathies ; chemically induced ; metabolism ; Cytokines ; metabolism ; Doxorubicin ; adverse effects ; Irbesartan ; Male ; Myocytes, Cardiac ; metabolism ; Rats ; Rats, Sprague-Dawley ; Tetrazoles ; pharmacology ; Ventricular Remodeling ; drug effects

OBJECTIVETo investigate of the regulatory effect of Rho-kinase pathway activation on angiotensin II (Ang II)-induced contraction of human airway smooth muscle cells (HASMCs) in vitro.

METHODSCultured primary HASMCs were divided into control group, AngII group, AngII + irbesartan group and AngII + Y-27632 group with corresponding treatment. AngII-induced contraction of HASMCs was evaluated using collagen gel lattices and observed morphologically using immunofluorescence assay. Western Blotting was significantly performed to examine the protein expression of Rho-kinase signal pathway.

RESULTSAngII-induced HASMC contraction was inhibited by treatments with irbesartan and Y-27632 as shown by gel contraction assay (P<0.001). Y-27632 treatment produced a stronger inhibitory effect than irbesartan on the expression of phosphorylated moesin, a substrate of Rho kinase (P<0.05).

CONCLUSIONAngII induces the contraction of HASMCs partially as a result of activation of Rho-kinase pathway.

Amides ; pharmacology ; Angiotensin II ; pharmacology ; Asthma ; physiopathology ; Biphenyl Compounds ; pharmacology ; Bronchi ; cytology ; Humans ; Muscle Contraction ; drug effects ; Muscle, Smooth ; cytology ; Primary Cell Culture ; Pyridines ; pharmacology ; Signal Transduction ; drug effects ; Tetrazoles ; pharmacology ; rho-Associated Kinases ; metabolism