Obesity: effects of physical exercise and metformin on metabolic aspects of monosodium glutamate treated rats

The present study investigated the effects of swimming training and metformin on metabolic aspects of obese rats. Wistar rats were divided into control (C), obese (O), Trained Obese (TO) and metformin obese (MO) groups. Obesity was induced by subcutaneous monosodium glutamate injection (4 mg/g body weight). Exercise program consisted in swimming 1 h/day, 5 days/week, for 8 weeks, supporting a load corresponding to 5% of body weight. Metformin was dissolved in the drinking water (1.4 mg/ml) for 8 weeks. At the end of the experimental period, rats were sacrificed and blood was collected for determinations of serum glucose, insulin and triglycerides and hematocrit. Samples of gastrocnemius muscle and liver were removed to evaluate triglycerides content MSG-induced obesity, increased serum glucose, insulin and triglycerides, while physical training was able to recover serum glucose and insulin and metformin treatment recovered serum insulin and slightly reduced the serum glucose. MSG-induced obesity also increased liver triglycerides content and physical training and metformin administration recovered these parameters. It was concluded that in MSG obese rats, physical exercise and metformin induced important metabolic alterations associated with an improvement in glucose homeostasis and in liver fat content. Obesity and Metabolism 2009; 5: 129-133.

Cellular and extracellular behavior in the gerbil (Meriones unguiculatus) ventral prostate following different types of castration and the consequences of testosterone replacement

Mongolian gerbils (Meriones unguiculatus) were grouped into two experimental groups: GEx.01 suffered orchiectomy and after 30 days received doses of testosterone cipionate (T), while GEx.02 received weekly and alternated doses of the anti-androgens cyproterone acetate and flutamide for 30 days, and the animals were then euthanized. Structural evaluation reveals a more intense reduction in epithelial height in GEx.02. Smooth muscle cells (SMC) presented a star-shaped aspect after 30 days of hormonal ablation and basal membrane was shown to be more intensely grooved in GEx.01. In both groups, after hormonal replacement, recovery in epithelial height could be noted and the SMC presented its phenotypes, but an increase in RER was seen, characterizing a modulation from its contractile to secreting phenotype. In conclusion, the prostate presented involution capacity after androgen ablation and the ability to reorganize after hormonal replacement, but events resulting from orchiectomy and subsequent T replacement were shown to be more aggressive to the prostate. (c) 2006 International Federation for Cell Biology. Published by Elsevier Ltd. All rights reserved.

Differential distribution of some extracellular matrix fibers in an experimentally denervated rat megaileum

Absence of enteric neurons is associated with thickening of the intestinal muscularis externa in Chagas' disease. The thickening is due to hyperplasia and hypertrophy of the smooth muscle cells and increased extracellular matrix components. The influence of the nervous system on the structure of the smooth muscle cells and its associated matrix has been poorly investigated. An experimental model of denervation of the ileum in rats was performed by application of the surfactant agent benzalkonium chloride that selectively destroys the myenteric plexus. Three months later, ileal tissue samples were obtained and studied by histochemistry and transmission electron microsocopy. Sham operated rats were used as controls. The diameter of collagen fibrils was evaluated in electron micrographs. The histopathological analysis showed thickening of the muscular layer. The thin and weakly arranged collagen and reticulin fibers surrounding the smooth muscle cells, observed in control cases by Picrosirius polarization (PSP) stain method, corresponded to a population of loosely packed thin collagen fibrils of uniform diameters (mean = 29.16 nm) at the ultrastructural level. In contrast, the thick and strongly birefringent fibers around the muscle cells, observed in the treated group, stained by PSP, corresponded to densely packed thicker fibrils with large variation in diameter (mean = 39.41 nm). Comparison of the data demonstrated statistically significant difference between the groups suggesting that the replacement of loosely arranged reticulin fibers by fibrous tissue (with typical collagen fiber), may alter the biomechanical function resulting in impairment of muscular contraction. (c) 2007 Elsevier Ltd. All rights reserved.

Microscopical Evaluation of Extracellular Matrix and Its Relation to the Palatopharyngeal Muscle in Obstructive Sleep Apnea

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Long-term inhibition of 5-alpha reductase and aromatase changes the cellular and extracellular compartments in gerbil ventral prostate at different postnatal ages

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

Effects of myenteric denervation on extracellular matrix fibers and mast cell distribution in normal stomach and gastric lesions

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

Glyceraldehyde-3-phosphate dehydrogenase of Paracoccidioides brasiliensis is a cell surface protein involved in fungal adhesion to extracellular matrix proteins and interaction with cells

The pathogenic fungus Paracoccidioides brasiliensis causes paracoccidioidomycosis, a pulmonary mycosis acquired by inhalation of fungal airborne propagules, which may disseminate to several organs and tissues, leading to a severe form of the disease. Adhesion to and invasion of host cells are essential steps involved in the infection and dissemination of pathogens. Furthermore, pathogens use their surface molecules to bind to host extracellular matrix components to establish infection. Here, we report the characterization of the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) of P. brasiliensis as an adhesin, which can be related to fungus adhesion and invasion. The P. brasiliensis GAPDH was overexpressed in Escherichia coli, and polyclonal antibody against this protein was obtained. By immunoelectron microscopy and Western blot analysis, GAPDH was detected in the cytoplasm and the cell wall of the yeast phase of P. brasiliensis. The recombinant GAPDH was found to bind to fibronectin, laminin, and type I collagen in ligand far-Western blot assays. of special note, the treatment of P. brasiliensis yeast cells with anti-GAPDH polyclonal antibody and the incubation of pneumocytes with the recombinant protein promoted inhibition of adherence and internalization of P. brasiliensis to those in vitro-cultured cells. These observations indicate that the cell wall-associated form of the GAPDH in P. brasiliensis could be involved in mediating binding of fungal cells to fibronectin, type I collagen, and laminin, thus contributing to the adhesion of the microorganism to host tissues and to the dissemination of infection.

Commissural NTS contributes to pressor responses to glutamate injected into the medial NTS of awake rats

In the present study we investigated whether interruption of the chemoreceptor reflex by an electrolytic lesion of the commissural subnucleus of the nucleus tractus solitarii (commNTS) influenced presser and bradycardic responses induced by microinjection of L-glutamate (L-Glu) into the medial NTS (mNTS) of conscious rats. Seven days after sham lesions, seven rats demonstrated significant presser [change in mean arterial pressure (MAP) = +33 +/- 3 mmHg] and bradycardic [change in heart rate (HR) = -74 +/- 8 beats/min (bpm)] responses to chemoreceptor reflex activation by intravenous injection of KCN. Likewise, L-Glu (1 nmol in 100 nl) injected into the mNTS in sham rats induced presser (+29 +/- 2 mmHg) and bradycardic responses (-90 +/- 8 bpm). However, in 11 rats with lesions in commNTS, presser and bradycardic chemoreceptor reflex responses were abolished, and injection of L-Glu into the mNTS decreased MAP (-14 +/- 6 mmHg) and HR (-59 +/- 16 bpm) as is reported in anesthetized control rats. We conclude that presser responses induced by L-Glu microinjected into the baroreceptor reflex region of mNTS in conscious rats depend on the integrity of the commNTS, which plays an important role in central chemoreceptor reflex pathways.

Production of extracellular alkaline proteases by Aspergillus clavatus

The production of extracellular alkaline proteases from Aspergillus clavatus was evaluated in a culture filtrate medium, with different carbon and nitrogen sources. The fungus was cultivated at three different temperatures during 10 days. The proteolytic activity was determined on casein pH 9.5 at 37degreesC. The highest alkaline proteolytic activity (38 U/ml) was verified for culture medium containing glucose and casein at 1% (w/v) as substrates, obtained from cultures developed at 25degreesC for 6 days. Cultures developed in Vogel medium with glucose at 2% (w/v) and 0.2% (w/v) NH4NO3 showed higher proteolytic activity (27 U/ml) when compared to the cultures with 1% of the same sugar. Optimum temperature was 40degreesC and the half-lives at 40, 45 and 50degreesC were 90, 25 and 18 min, respectively. Optimum pH of enzymatic activity was 9.5 and the enzyme was stable from pH 6.0 to 12.0.

Collagen type VI is a component of the extracellular matrix microfibril network of the prostatic stroma

Stroma-epithelium relationships are of great relevance in prostatic morphogenesis and physiology, However, little knowledge exists about either stromal cells or extracellular matrix composition and arrangement in this system, Ultrastructural analysis revealed the existence of a microfibrillar system which occupies large areas of the rat prostatic stroma, In this work, we have applied immunocytochemistry and an ATP treatment for the ultrastructural identification of collagen type VI microfibrils, aiming at examining its participation in the prostatic microfibrillar network. Immunocytochemistry was also extended to a human case of prostatic nodular hyperplasia, Both methods succeeded in identifying collagen type VI in the rat ventral prostate, Collagen type VI is evenly distributed throughout the stroma but mainly associated with the basal lamina, collagen fibrils, and around the stromal cells, the use of ATP treatment allowed for the discrimination between collagen type VI and elastin-associated microfibrils, and demonstrated that these two classes of microfibrils establish an extended, mixed, and open network. The same aspects of association with the basal lamina, with stromal cells (particularly with smooth muscle cells), and with fibrillar components of the stroma were observed in the human tissue, We suggest that the collagen type VI and elastin-associated microfibril system may be involved in the control of some aspects of cellular behavior and may also play a structural role, maintaining the organ integrity after the deformations occurring under smooth muscle contraction.