Plasma lipid profile of experimentally induced hyperlipidemic New Zealand white rabbits is not affected by resveratrol

Hyperlipidemia is well recognized as an important risk factor in the development of atherosclerosis. Low-density lipoproteins (LDL) are components of cholesterol that are highly associated to an increased risk of cardiovascular diseases. Hypercholesterolemia induces proteolytic and oxidative changes in vasculature, leading to a local inflammatory response. Since dietary antioxidants have attracted considerable attention as preventive and therapeutic agents, the polyphenolic compound resveratrol seems to play an important role in prevention of human atherosclerosis. Researches show that resveratrol inhibits LDL oxidation and platelet aggregation, as well as vascular prolifer ation of smooth muscle cells. However, recent findings in animal models reveal conflicting results regarding its effects on plasma lipid levels. The aim of the present study was to evaluate the effect of resveratrol on plasma biochemistry profile in New Zealand white rabbits submitted to a hypercholesterolemic diet. Twenty healthy, male, adult New Zealand white rabbits were fed with ordinary diet for one week before being divided into four treatment groups, containing five animals each. Group CT received maintenance diet; group R received maintenance diet and resveratrol (3mg/kg/day) given orally; group CL received maintenance diet enriched with 1.5% cholesterol; and group CR received maintenance diet enriched with 1.5% cholesterol and resveratrol (3mg/kg/day) given orally. During the experiment, from each animal, samples of 3mL venous blood were collected in heparin twice monthly for measurements of total cholesterol, triglycerides, and low- and high-density lipoproteins. The data analysis revealed that resveratrol did not have a hypolipidemic effect in experimentally induced hypercholesterolemic New Zealand white rabbits.

Arquitetura da parede vascular de segmentos torácico e abdominais da aorta de macaco prego (Cebus apella)

The intimal layer of the thoracic and abdominal aortic segments of Cebus apella monkey presented an evident inner elastic lamina. The medial layer of the thoracic aorta segment showed a basic lamellar elastic pattern having a medium average of 23.12 lamellae per analyzed cut sections, which appeared disposed circular and oblique relatively to the aortic lumen. The aortic adventitial layer, at this level, was formed mainly by collagen fibers, irregularly disposed between elastic fibers and smooth muscle cells. The aortic abdominal portion, in this monkey, at the suprarenal level presented a medium number of 19.12 elastic lamellae which showed a relatively disorganized and broken up pattern. At the infrarenal level the aortic medium layer showed a medium average of 11.75 elastic lamellae and next to the emission of the internal iliac arteries it was found only a middle average of 8.37 elastic lamellae intermingled with smooth muscle cells and collagen fibers whose concentration seemed to be increased next to the adventitial layer. The external elastic lamina was only present in the more distal aortic segment near to the emission of the internal iliac arteries.

Avaliação do efeito do tempo de desossa sobre a qualidade da carne de peito de matrizes pesadas de descarte

The aim of this study was to evaluate the effect of deboning time on broiler breeder hen meat for in natura consumption. Eighty samples of breast fillets with bone (Pectoralis major muscle) were collected and divided into four groups of 20 samples each; each group represented a different post-mortem deboning time: 0 (immediately after cooling), 4, 8 and 12h post-mortem. At 24h post-mortem, all samples were evaluated for the following parameters: pH, color (L*, a* and b*), cooking loss, water retention capacity, shear force, myofibrillar fragmentation index and fiber diameter. Color (L*, a* and b*), cooking loss, water retention capacity and shear force were significantly different (p ≥ 0.05) among the evaluated deboning times. The shear force value of breast fillets deboned at 0h post-mortem (8.478) was significantly different (p ≥ 0.05) from those deboned at 4, 8 and 12h post-mortem (5.154; 5.375 and 4.819, respectively). Therefore, an increase in the tenderness of breast fillets was observed, when deboning was performed at least 4h post-mortem.

Exercise training ameliorates the impairment of endothelial and nitrergic corpus cavernosum responses in diabetic rats

Aims: The effect of exercise training (ET) on vascular responsiveness in diabetes mellitus has been largely well studied. However, limited studies have investigated the effects of ET on functional responses of the corpus cavernosum (CC) in diabetic animals. Therefore, the aim of this study was to investigate whether prior ET prevents the impairment of erectile function in streptozotocin-induced diabetic rats. Main methods: Rats were exercised for four weeks prior to the induction of diabetes, and then again for another 4 weeks thereafter. Concentration-response curves to acetylcholine, sodium nitroprusside, Y-27632, BAY 412272 and phenylephrine (PE) were obtained in CC. The excitatory and inhibitory effects of electrical-field stimulation were also evaluated. Key findings: Plasma SOD levels were markedly decreased in the sedentary diabetic group (D-SD) as compared to control sedentary animals (C-SD), approximately 53% (P < 0.05) and this reduction was restored in trained diabetic animals. Physical training restored the impairment of endothelium-dependent and -independent relaxation responses seen in the D-SD group. The potency values for Y-27632 in the CC were significantly reduced in the D-SD group, which was reversed by physical training. The impairment of electrical-field stimulation (EFS)-induced relaxation seen in the D-SD group was restored by physical training. On the other hand, both EFS-induced contractions and concentration-response curves to PE in cavernosal strips were not modified by either diabetes or physical training. Significance: Practice of regular physical exercise may be an important approach in preventing erectile dysfunction associated with diabetes mellitus by re-establishment of the balance between NO production and its inactivation. © 2010 Elsevier Inc. All rights reserved.

Prostatic stromal cells of old gerbils respond to steroidal blockades creating a microenvironment similar to reactive stroma

The present study examined the changes in prostatic stroma of old gerbils (18 months) submitted to orchiectomy associated or not with steroidal blockades. Animals were divided into six groups, all surgically castrated except the control group composed of intact animals. The other two controls were formed by castrated animals, one that received and one that did not receive the drug vehicle. In the experimental groups, doses of flutamide (10 mg/kg/day) and/or tamoxifen (1 mg/kg/48 h) were applied for 1, 3, 7 and 30 days post-castration. The methodologies involved were: morphological (HE, Gömöri reticulin, Picrosirius-hematoxylin), immunohistochemical (tenascin, type IV collagen) and ultrastructural analyses. Gradually, the epithelial compartment was significantly exceeded in volume by the stromal compartment, characterizing regression but not atrophy of the gland. The smooth muscle cell frequency increased significantly after 30 days and participated effectively in the stromal increase. Large collagen I and tenascin deposits in the subepithelial region were a hallmark of prostatic acini in the experimental groups up to 7 days, while in the 30-day group these elements practically disappear. Fibroblasts with reactive aspect, changes in basement membrane structure and maintenance and/or increase of blood vessels were also associated with treatments. These results showed, in part, the sensitivity of stromal components to suppressed hormones and favored the creation of a differentiated glandular microenvironment. Therefore, the data suggest the importance of considering aging when analyzing aspects of prostatic regression between rodents and humans after hormonal ablation. © 2011 Elsevier Masson SAS. All rights reserved.

Evaluation of intracellular calcium in golden retriever muscular dystrophy

The present study had the objective of evaluating calcium accumulations in muscle fibers and their correlation with the canine muscular dystrophy. After the deaths of the animals (13 dystrophic and 3 non-dystrophic), samples of the skeletal muscles were collected. The material was stained with hematoxylin-eosin, Gomori's modified trichrome and alizarin red S technique (pH 4.3). The histopathological changes were analyzed and the proportions of calcium-positive (CPF) and negative muscle fibers were evaluated. Histopathological changes such as muscle fiber diameter changes, necrosis, hyalinization, presence of inflammatory infiltrate and fatty atrophy were identified in all the dystrophic muscles. Statistically significant differences in numbers of CPF between dystrophic muscles and non-dystrophics were observed for the masseter (6%), brachial biceps (5%) and triceps, sartorius and femoral biceps (4%) muscles. The identifying calcium is of interest as a parameter for helping in diagnostic screening.

MMP-2 and TIMP-2 in the prostates of male and female mongolian gerbils: Effects of hormonal manipulation

TIMPs in the prostates of male and female gerbils and evaluated the effects of testosterone on the expression of these enzymes. Ventral prostates from male gerbils that were either intact or had been castrated for 7 or 21 days, along with prostates from female gerbils that were either intact or had been treated with testosterone for 7 or 21 days, were submitted to histological, stereological and immunohistochemical analyses. Stereology of prostatic components showed significant alterations of tissue compartments in the ventral male prostate after castration, especially after 21 days, with a significant increase in stroma. Administration of testosterone led to disorganization in the female prostate, with a significant increase in collagen fibers and smooth muscle cells after 21 days, along with the development of epithelial lesions such as PINs. MMP-2 increased after 21 days of castration in males; however, the TIMP-2 immunoreaction for this group was weak or absent. In females, the expression of MMP-2 appeared to decrease after 7 days of treatment with testosterone, but after 21 days, both epithelium and stroma showed a stronger reaction for MMP-2 than the controls. The expression of TIMP-2 in the treated females was similar to its expression in the castrated males. We conclude that the distribution of MMPs and TIMPs in both male and female prostates is altered by androgen manipulation, but the mechanism of stromal regulation appears to be distinct between genders because both the lack of T in castrated males and the excess levels of T in treated females lead to the same effect.

Involvement of the atrial natriuretic peptide in cardiovascular pathophysiology and its relationship with exercise

In this minireview we describe the involvement of the atrial natriuretic peptide (ANP) in cardiovascular pathophysiology and exercise. The ANP has a broad homeostatic role and exerts complex effects on the cardio-circulatory hemodynamics, it is produced by the left atrium and has a key role in regulating sodium and water balance in mammals and humans. The dominant stimulus for its release is atrial wall tension, commonly caused by exercise. The ANP is involved in the process of lipolysis through a cGMP signaling pathway and, as a consequence, reducing blood pressure by decreasing the sensitivity of vascular smooth muscle to the action of vasoconstrictors and regulate fluid balance. The increase of this hormone is associated with better survival in patients with chronic heart failure (CHF). This minireview provides new evidence based on recent studies related to the beneficial effects of exercise in patients with cardiovascular disease, focusing on the ANP. © 2012 de Almeida et al; licensee BioMed Central Ltd.

Cimetidine-induced vascular cell apoptosis impairs testicular microvasculature in adult rats

Cimetidine, an H2 receptor antagonist used for treatment of gastric ulcers, exerts antiandrogenic and antiangiogenic effects. In the testes cimetidine impairs spermatogenesis, Sertoli cells and peritubular tissue, inducing apoptosis in the myoid cells. Regarding the importance of histamine and androgens for vascular maintenance, the effect of cimetidine on the structural integrity of the testicular vasculature was evaluated. Adult male rats received cimetidine (CMTG) and saline (CG) for 50 days. The testes were fixed in buffered 4% formaldehyde and embedded in historesin and paraffin. In the PAS-stained sections, the microvascular density (MVD) and the vascular luminal area (VLA) were obtained. TUNEL method was performed for detection of cell death. Testicular fragments embedded in Araldite were analyzed under transmission electron microscopy. A significant decrease in the MVD and VLA and a high number of collapsed blood vessel profiles were observed in CMTG. Endothelial cells and vascular muscle cells were TUNEL-positive and showed ultrastructural features of apoptosis. These results indicate that cimetidine induces apoptosis in vascular cells, leading to testicular vascular atrophy. A possible antagonist effect of cimetidine on the H2 receptors and/or androgen receptors in the vascular cells may be responsible for the impairment of the testicular microvasculature.

Genome-Wide Analysis Reveals Selection for Important Traits in Domestic Horse Breeds

Intense selective pressures applied over short evolutionary time have resulted in homogeneity within, but substantial variation among, horse breeds. Utilizing this population structure, 744 individuals from 33 breeds, and a 54,000 SNP genotyping array, breed-specific targets of selection were identified using an FST-based statistic calculated in 500-kb windows across the genome. A 5.5-Mb region of ECA18, in which the myostatin (MSTN) gene was centered, contained the highest signature of selection in both the Paint and Quarter Horse. Gene sequencing and histological analysis of gluteal muscle biopsies showed a promoter variant and intronic SNP of MSTN were each significantly associated with higher Type 2B and lower Type 1 muscle fiber proportions in the Quarter Horse, demonstrating a functional consequence of selection at this locus. Signatures of selection on ECA23 in all gaited breeds in the sample led to the identification of a shared, 186-kb haplotype including two doublesex related mab transcription factor genes (DMRT2 and 3). The recent identification of a DMRT3 mutation within this haplotype, which appears necessary for the ability to perform alternative gaits, provides further evidence for selection at this locus. Finally, putative loci for the determination of size were identified in the draft breeds and the Miniature horse on ECA11, as well as when signatures of selection surrounding candidate genes at other loci were examined. This work provides further evidence of the importance of MSTN in racing breeds, provides strong evidence for selection upon gait and size, and illustrates the potential for population-based techniques to find genomic regions driving important phenotypes in the modern horse. © 2013 Petersen et al.

Structural and ultrastructural evidence for telocytes in prostate stroma

The prostate comprises a glandular epithelium embedded within a fibromuscular stroma. The stroma is a complex arrangement of cells and extracellular matrix (ECM) components in addition to growth factors, regulatory molecules, remodelling enzymes, blood vessels, nerves and immune cells. The principal sources of ECM components are fibroblasts and smooth muscle cells (SMC), which synthesize the structural and regulatory components of the ECM. Telocytes (TCs) were recently described as a novel stromal cell type that exhibited characteristic features. The aim of this study was to confirm the presence of TCs in prostate stromal tissue of gerbils, as the stromal compartment of this gland is a dynamic microenvironment. We used transmission electron microscopy (TEM), light microscopy and immunohistochemistry methods to provide morphological evidence for the presence of TCs. Cells that resembled TCs were observed in gerbil prostatic stroma. These cells had small cellular bodies with very thin and extremely long cellular processes. They were found primarily in the subepithelial area and also at the periphery of SMC layers. TCs also exhibited moniliform processes, caveolae and nuclei surrounded by small amounts of cytoplasm. Close contacts between TC podomers were evident, particularly in the adjacent epithelial compartment. This morphological evidence supported the presence of TCs in the gerbil prostatic stroma, which we report for the first time. © 2013 The Authors. Published by Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

A new proposed rodent model of chemically induced prostate carcinogenesis: Distinct time-course prostate cancer progression in the dorsolateral and ventral lobes

Background. Characterization of novel rodent models for prostate cancer studies requires evaluation of either spontaneous and carcinogen-induced tumors as well as tumor incidence in different prostatic lobes. We propose a new short-term rodent model of chemically induced prostate carcinogenesis in which prostate cancer progression occurs differentially in the dorsolateral and ventral lobes. Methods. Adult gerbils were treated with MNU alone or associated with testosterone for 3 or 6 months of treatment. Tumor incidence, latency, localization, and immunohistochemistry (AR, PCNA, smooth muscle α-actin, p63, MGMT, and E-cadherin) were studied in both lobes. Results. Comparisons between both lobes revealed that lesions developed first in the DL while the VL presented longer tumor latency. However, after 6 months, there was a dramatic increase in tumor multiplicity in the VL, mainly in MNU-treated groups. Lesions clearly progressed from a premalignant to a malignant phenotype over time and tumor latency was decreased by MNU + testosterone administration. Three-dimensional reconstruction of the prostatic complex showed that the DL developed tumors exclusively in the periurethral area and showed intense AR, PCNA, and MGMT immunostaining. Moreover, VL lesions emerged throughout the entire lobe. MNU-induced lesions presented markers indicative of an aggressive phenotype: lack of basal cells, rupture of the smooth muscle cell layer, loss of E-cadherin, and high MGMT staining. Conclusions. There are distinct pathways involved in tumor progression in gerbil prostate lobes. This animal provides a good model for prostate cancer since it allows the investigation of advanced steps of carcinogenesis with shorter latency periods in both lobes. Copyright © 2013 Wiley Periodicals, Inc.

Alterações do colágeno e do sistema elástico induzidas pela hiperatividade do detrusor em coelhos: ação da oxibutinina

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desempenho produtivo e crescimento muscular de linhagens de tilápia-do-nilo cultivadas na fase inicial

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudo morfológico e modulações dos tipos de fibras do m. reto femoral de ratos wistar, após a estimulação com corrente russa

Pós-graduação em Ciências da Motricidade - IBRC