Avaliação da atividade eletromecânica uterina em ratas por biosusceptometria AC e eletromiografia

Pós-graduação em Biologia Geral e Aplicada - IBB

MMP-2 and TIMP-2 in male and female prostates of mongolian gerbil: effects of hormonal manipulation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação histológica e funcional do enxerto de neotraqueia de coelho desenvolvido por bioengenharia

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação histológica e funcional do enxerto de neotraqueia de coelho desenvolvido por bioengenharia

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Histomorphometric analysis of the effects of creatine on rat myometrium

Objective: To analyze the myometrial thickness of rats subjected to creatine (Cr) ingestion. Study design: A total of 14 rats was equally divided into the control group (ConGr) receiving 1 ml potable water and the creatine group (CrGr) subjected to the ingestion of 1.6 g/kg Cr diluted in 1 ml potable water. At the end of 8 weeks, the animals were anesthetized (xylazine and ketamine) and sacrificed, the uteri and ovaries stained with hematoxylin and eosin, the thickness of both the myometrium and the epithelium measured and the follicles counted. Results: Analysis revealed a significant increase in thickness of the myometrium in the CrGr (272.26 +/- 66.71 mu m) contrasted with that from the ConGr (160.76 +/- 35.65 mu m), CrGr > ConGr (p < 0001). Conclusion: Our data suggest that Cr changed myometrial morphology in rats by enhancing myometrial thickness, but its action mechanism in the smooth muscle is still unclear.

Thioredoxin interacting protein genetic variation is associated with diabetes and hypertension in the Brazilian general population

Objective: To investigate the relationship between TXNIP polymorphisms, diabetes and hypertension phenotypes in the Brazilian general population. Methods: Five hundred seventy-six individuals randomly selected from the general urban population according to the MONICA-WHO project guidelines were phenotyped for cardiovascular risk factors. A second, independent, sample composed of 487 family-trios from a different site was also selected. Nine TXNIP polymorphisms were studied. The potential association between TXNIP variability and glucose-phenotypes in children was also explored. TXNIP expression was quantified by real-time PCR in 53 samples from human smooth muscle cells primary culture. Results: TXNIP rs7211 and rs7212 polymorphisms were significantly associated with glucose and blood pressure related phenotypes. In multivariate logistic regression models the studied markers remained associated with diabetes even after adjustment for covariates. TXNIP rs7211 T/rs7212 G haplotype (present in approximately 17% of individuals) was significantly associated to diabetes in both samples. In children, the TXNIP rs7211 T/rs7212 G haplotype was associated with fasting insulin concentrations. Finally, cells harboring TXNIP rs7212 G allele presented higher TXNIP expression levels compared with carriers of TXNIP rs7212 CC genotype (p = 0.02). Conclusion: Carriers of TXNIP genetic variants presented higher TXNIP expression, early signs of glucose homeostasis derangement and increased susceptibility to chronic metabolic conditions such as diabetes and hypertension. Our data suggest that genetic variation in the TXNIP gene may act as a "common ground" modulator of both traits: diabetes and hypertension. (C) 2011 Elsevier Ireland Ltd. All rights reserved.

The adipokine chemerin augments vascular reactivity to contractile stimuli via activation of the MEK-ERK1/2 pathway

Aims: Cytokines interfere with signaling pathways and mediators of vascular contraction. Endothelin-1 (ET-1) plays a major role on vascular dysfunction in conditions characterized by increased circulating levels of adipokines. In the present study we tested the hypothesis that the adipokine chemerin increases vascular contractile responses via activation of ET-1/ET-1 receptors-mediated pathways. Main methods: Male, 10-12 week-old Wistar rats were used. Endothelium-intact and endothelium-denuded aortic rings were incubated with chemerin (0.5 ng/mL or 5 ng/mL, for 1 or 24 h), and isometric contraction was recorded. Protein expression was determined by Western blotting. Key findings: Constrictor responses to phenylephrine (PE) and ET-1 were increased in vessels treated for 1 h with chemerin. Chemerin incubation for 24 h decreased PE contractile response whereas it increased the sensitivity to ET-1. Endothelium removal significantly potentiated chemerin effects on vascular contractile responses to PE and ET-1. Incubation with either an ERK1/2 inhibitor (PD98059) or ETA antagonist (BQ123) abolished chemerin effects on PE- and ET-1-induced vasoconstriction. Phosphorylation of MEK1/2 and ERK1/2 was significantly increased in vessels treated with chemerin for 1 and 24 h. Phosphorylation of these proteins was further increased in vessels incubated with ET-1 plus chemerin. ET-1 increased MEK1/2, ERK1/2 and MKP1 protein expression to values observed in vessels treated with chemerin. Significance: Chemerin increases contractile responses to PE and ET-1 via ERK1/2 activation. Our study contributes to a better understanding of the mechanisms by which the adipose tissue affects vascular function and, consequently, the vascular alterations present in obesity and related diseases. (c) 2012 Elsevier Inc. All rights reserved.

Expression of the P2X(2) receptor in different classes of ileum myenteric neurons in the female obese ob/ob mouse

AIM: To examine whether the ob/ob mouse model of obesity is accompanied by enteric nervous system abnormalities such as altered motility. METHODS: The study examined the distribution of the P2X(2) receptor (P2X(2)R) in myenteric neurons of female ob/ob mice. Specifically, we used immunohistochemistry to analyze the co-expression of the P2X(2)R with neuronal nitric oxide synthase (nNOS), choline acetyltransferase (ChAT), and calretinin (CalR) in neurons of the small intestine myenteric plexus in ob/ob and control female mice. In these sections, we used scanning confocal microscopy to analyze the co-localization of these markers as well as the neuronal density (cm(2)) and area profile (mu m(2)) of P2X(2)R-positive neurons. In addition, enteric neurons were labeled using the nicotinamide adenine dinucleotide (NADH) diaphorase method and analyzed with light microscopy as an alternate means by which to analyze neuronal density and area. RESULTS: In the present study, we observed a 29.6% increase in the body weight of the ob/ob animals (OG) compared to the control group (CG). In addition, the average small intestine area was increased by approximately 29.6% in the OG compared to the CG. Immunoreactivity (IR) for the P2X(2)R, nNOS, ChAT and CaIR was detectable in the myenteric plexus, as well as in the smooth muscle, in both groups. This IR appeared to be mainly cytoplasmic and was also associated with the cell membrane of the myenteric plexus neurons, where it outlined the neuronal cell bodies and their processes. P2X(2)R-IR was observed to co-localize 100% with that for nNOS, ChAT and CaIR in neurons of both groups. In the ob/ob group, however, we observed that the neuronal density (neuron/cm(2)) of P2X(2)R-IR cells was increased by 62% compared to CG, while that of NOS-IR and ChAT-IR neurons was reduced by 49% and 57%, respectively, compared to control mice. The neuronal density of CaIR-IR neurons was not different between the groups. Morphometric studies further demonstrated that the cell body profile area (mu m(2)) of nNOS-IR, ChAT-IR and CaIR-IR neurons was increased by 34%, 20% and 55%, respectively, in the OG compared to controls. Staining for NADH diaphorase activity is widely used to detect alterations in the enteric nervous system; however, our qualitative examination of NADH-diaphorase positive neurons in the nnyenteric ganglia revealed an overall similarity between the two groups. CONCLUSION: We demonstrate increases in P2X(2)R expression and alterations in nNOS, ChAT and CaIR IR in ileal myenteric neurons of female ob/ob mice compared to wild-type controls. (c) 2012 Baishideng. All rights reserved.

Action of ANP on the nongenomic dose-dependent biphasic effect of aldosterone on NHE1 in proximal S3 segment

The rapid (2 min) nongenomic effects of aldosterone (ALDO) and/or spironolactone (MR antagonist), RU 486 (GR antagonist), atrial natriuretic peptide (ANP) and dimethyl-BAPTA (BAPTA) on the intracellular pH recovery rate (pHirr) via NHE1 (basolateral Na+/H+ exchanger isoform), after the acid load induced by NH4Cl, and on the cytosolic free calcium concentration ([Ca2+](i)) were investigated in the proximal S3 segment isolated from rats, by the probes BCECF-AM and FLUO-4-AM, respectively. The basal pHi was 7.15+/-0.008 and the basal pHirr was 0.195+/-0.012 pH units/min (number of tubules/number of tubular areas = 16/96). Our results confirmed the rapid biphasic effect of ALDO on NHE1: ALDO (10(-12) M) increases the pHirr to approximately 59% of control value, and ALDO (10(-6)M) decreases it to approximately 49%. Spironolactone did not change these effects, but RU 486 inhibited the stimulatory effect and maintained the inhibitory effect. ANP (10(-6) M) or BAPTA (5 x 10(-5) M) alone had no significant effect on NHE1 but prevented both effects of ALDO on this exchanger. The basal [Ca2+](i) was 104+/-3 nM (15), and ALDO (10(-12) or 10(-6) M) increased the basal [Ca2+](i) to approximately 50% or 124%, respectively. RU 486, ANP and BAPTA decreased the [Ca2+](i) and inhibited the stimulatory effect of both doses of ALDO. The results suggest the involvement of GR on the nongenomic effects of ALDO and indicate a pHirr-regulating role for [Ca2+](i) that is mediated by NHE1, stimulated/impaired by ALDO, and affected by ANP or BAPTA with ALDO. The observed nongenomic hormonal interaction in the S3 segment may represent a rapid and physiologically relevant regulatory mechanism in the intact animal under conditions of volume alterations. (C) 2011 Elsevier Ltd. All rights reserved.

Angiotensin II-induced JNK activation is mediated by NAD(P)H oxidase in isolated rat pancreatic islets

Angiotensin II (All), the active component of the renin angiotensin system (RAS), plays a vital role in the regulation of physiological processes of the cardiovascular system, but also has autocrine and paracrine actions in various tissues and organs. Many studies have shown the existence of RAS in the pancreas of humans and rodents. The aim of this study was to evaluate potential signaling pathways mediated by All in isolated pancreatic islets of rats. Phosphorylation of MAPKs (ERK1/2, JNK and p38MAPK), and the interaction between proteins JAK/STAT were evaluated. All increased JAK2/STAT1 (42%) and JAK2/STAT3 (100%) interaction without altering the total content of JAK2. Analyzing the activation of MAPKs (ERK1/2, JNK and p38MAPK) in isolated pancreatic islets from rats we observed that All rapidly (3 min) promoted a significant increase in the phosphorylation degree of these proteins after incubation with the hormone. Curiously JNK protein phosphorylation was inhibited by DPI, suggesting the involvement of NAD(P)H oxidase in the activation of protein. (C) 2012 Elsevier B.V. All rights reserved.

Endothelium dependent expression and underlying mechanisms of des-Arg(9)-bradykinin-induced B1R-mediated vasoconstriction in rat portal vein

Endothelial dysfunction has been implicated in portal vein obstruction, a condition responsible for major complications in chronic portal hypertension. Increased vascular tone due to disruption of endothelial function has been associated with an imbalance in the equilibrium between endothelium-derived relaxing and contracting factors. Herein, we assessed underlying mechanisms by which expression of bradykinin B-1 receptor (B1R) is induced in the endothelium and how its stimulation triggers vasoconstriction in the rat portal vein. Prolonged in vitro incubation of portal vein resulted in time- and endothelium-dependent expression of B1R and cyclooxygenase-2 (COX-2). Inhibition of protein kinase C (PKC) or phosphatidylinositol 3-kinase (PI3K) significantly reduced expression of B1R through the regulation of transcription factors, activator protein-1 (AP-1) and cAMP response element-binding protein (CREB). Moreover, pharmacological studies showed that B1R-mediated portal vein contraction was reduced by COX-2, but not COX-1, inhibitors. Notably, activation of endothelial B1R increased phospholipase A(2)/COX-2-derived thromboxane A(2) (TXA(2)) levels, which in turn mediated portal vein contraction through binding to TXA(2) receptors expressed in vascular smooth muscle cells. These results provide novel molecular mechanisms involved in the regulation of B1R expression and identify a critical role for the endothelial B1R in the modulation of portal vein vascular tone. Our study suggests a potential role for B1R antagonists as therapeutic tools for diseases where portal hypertension may be involved. (C) 2012 Elsevier Inc. All rights reserved.

Acute ethanol intake induces superoxide anion generation and mitogen-activated protein kinase phosphorylation in rat aorta: A role for angiotensin type 1 receptor

Ethanol intake is associated with increase in blood pressure, through unknown mechanisms. We hypothesized that acute ethanol intake enhances vascular oxidative stress and induces vascular dysfunction through renin-angiotensin system (RAS) activation. Ethanol (1 g/kg; p.o. gavage) effects were assessed within 30 min in male Wistar rats. The transient decrease in blood pressure induced by ethanol was not affected by the previous administration of losartan (10 mg/kg; p.o. gavage), a selective ATI receptor antagonist. Acute ethanol intake increased plasma renin activity (PRA), angiotensin converting enzyme (ACE) activity, plasma angiotensin I (ANG I) and angiotensin II (ANG II) levels. Ethanol induced systemic and vascular oxidative stress, evidenced by increased plasma thiobarbituric acid-reacting substances (TBARS) levels, NAD(P) H oxidase-mediated vascular generation of superoxide anion and p47phox translocation (cytosol to membrane). These effects were prevented by losartan. Isolated aortas from ethanol-treated rats displayed increased p38MAPK and SAPK/JNK phosphorylation. Losartan inhibited ethanol-induced increase in the phosphorylation of these kinases. Ethanol intake decreased acetylcholine-induced relaxation and increased phenylephrine-induced contraction in endothelium-intact aortas. Ethanol significantly decreased plasma and aortic nitrate levels. These changes in vascular reactivity and in the end product of endogenous nitric oxide metabolism were not affected by losartan. Our study provides novel evidence that acute ethanol intake stimulates RAS activity and induces vascular oxidative stress and redox-signaling activation through AT(1)-dependent mechanisms. These findings highlight the importance of RAS in acute ethanol-induced oxidative damage. (c) 2012 Elsevier Inc. All rights reserved.

Cerebral amyloid angiopathy impact on endothelium

Cerebral amyloid angiopathy (CAA) is an age-associated disease characterized by amyloid deposition in cerebral and meningeal vessel walls. CAA is detected in the majority of the individuals with dementia and also in a large number of non-demented elderly individuals. In addition, CAA is strongly associated with Alzheimer's disease (AD) pathology. Mechanical consequences including intra-cerebral or subarachnoid hemorrhage remains CAA most feared complication, but only a small fraction of CAA results in severe bleeding. On the hand the non-mechanical consequences in cerebrovascular regulation are prevalent and may be even more deleterious. Studies of animal models have provided strong evidence linking the vasoactive A beta 1-40, the main species found in CAA, to disturbances in endothelial-dependent factors, disrupting cerebrovascular regulation Here, we aimed to review experimental findings regarding the non-mechanical consequences of CAA for cerebrovascular regulation and discuss the implications of these results to clinical practice. (C) 2012 Elsevier Inc. All rights reserved.

Improvement of metabolic parameters and vascular function by metformin in obese non-diabetic rats

Aims: Metformin is an insulin sensitizing agent with beneficial effects in diabetic patients on glycemic levels and in the cardiovascular system. We examined whether the metabolic changes and the vascular dysfunction in monosodium glutamate-induced obese non-diabetic (MSG) rats might be improved by metformin. Main methods: 16 week-old MSG rats were treated with metformin for 15 days and compared with age-matched untreated MSG and non-obese non-diabetic rats (control). Blood pressure, insulin sensitivity, vascular reactivity and prostanoid release in the perfused mesenteric arteriolar bed as well as nitric oxide production and reactive oxygen species generation in isolated mesenteric arteries were analyzed. Key findings: 18-week-old MSG rats displayed higher Lee index, fat accumulation, dyslipidemia, insulin resistance and hyperinsulinemia. Metformin treatment improved these alterations. The norepinephrine-induced response, increased in the mesenteric arteriolar bed from MSG rats, was corrected by metformin. Indomethacin corrected the enhanced contractile response in MSG rats but did not affect metformin effects. The sensitivity to acetylcholine, reduced in MSG rats, was also corrected by metformin. Indomethacin corrected the reduced sensitivity to acetylcholine in MSG rats but did not affect metformin effects. The sensitivity to sodium nitroprusside was increased in preparations from metformin-treated rats. Metformin treatment restored both the reduced PGI2/TXA2 ratio and the increased reactive oxygen species generation in preparations from MSG rats. Significance: Metformin improved the vascular function in MSG rats through reduction in reactive oxygen species generation, modulation of membrane hyperpolarization. correction of the unbalanced prostanoids release and increase in the sensitivity of the smooth muscle to nitric oxide. (c) 2011 Elsevier Inc. All rights reserved.

Time course involvement of matrix metalloproteinases in the vascular alterations of renovascular hypertension

Increased vascular matrix metalloproteinases (MMPs) levels play a role in late phases of hypertensive vascular remodeling. However, no previous study has examined the time course of MMPs in the various phases of two-kidney, one-clip hypertension (2K1C). We examined structural vascular changes, collagen and elastin content, vascular oxidative stress, and MMPs levels/activities during the development of 2K1C hypertension. Plasma angiotensin converting enzyme (ACE) activity was measured to assess renin-angiotensin system activation. Sham or 2K1C hypertensive rats were studied after 2, 4, 6, and 10 weeks of hypertension. Systolic blood pressure (SBP) was monitored weekly. Morphometry of structural changes in the aortic wall was studied in hematoxylin/eosin, orcein and picrosirius red sections. Aortic NADPH activity and superoxide production was evaluated. Aortic gelatinolytic activity was determined by in situ zymography, and MMP-2, MMP-14, and tissue inhibitor of MMPs (TIMP)-2 levels were determined by gelatin zymography, immunofluorescence and immunohistochemistry. 2K1C hypertension was associated with increased ACE activity, which decreased to normal after 10 weeks. We found increased aortic collagen and elastin content in the early phase of hypertension, which were associated with vascular hypertrophy, increased vascular MMP-2 and MMP-14 (but not TIMP-2) levels, and increased gelatinolytic activity, possibly as a result of increased vascular NADPH oxidase activity and oxidative stress. These results indicate that vascular remodeling of renovascular hypertension is an early process associated with early increases in MMPs activities, enhanced matrix deposition and oxidative stress. Using antioxidants or MMPs inhibitors in the early phase of hypertension may prevent the vascular alterations of hypertension. (C) 2012 Elsevier B.V. All rights reserved.