Renata de Britto Mari

Fine Structure of the Dorsal Surface of Ostrich's (Struthio camelus) Tongue

The tongue of birds fills the oral cavity and has a beak-like shape. Morphological studies of birds reveal a correlation between the structure of the tongue and the mechanism of food intake and the type of food. However, several studies have shown morphological differences among the tongues of bird species. The aim of this study was to analyze ostrich tongue morphology and ultrastructural features using scanning electron microscopy. Tongues from 12 adult ostriches were examined. Six tongues were sectioned sagittally into lateral and middle portions, fixed in 10% formaldehyde solution, and examined under light microscopy. The other six samples were sectioned longitudinally, and the dorsal and ventral surfaces were separated, immersion-fixed in modified Karnovsky solution, and examined under scanning electron microscopy. The tongue surface of the ostrich was smooth, without lingual papillae, and covered by stratified non-keratinized epithelium. In the submucosal layer, mucous salivary glands were surrounded by connective-tissue capsules, with septa dividing the glands into lobes. Numerous salivary gland ducts of different sizes and connective-tissue laminae dividing each opening could be clearly seen in scanning electron microscope images. The ventral surface had fewer openings than the dorsal surface. In samples treated with NaOH, connective-tissue papillae from the dorsal region were oriented posteriorly.

Exercise reduces inhibitory neuroactivity and protects myenteric neurons from age-related neurodegeneration

The practice of regular exercise is indicated to prevent some motility disturbances in the gastrointestinal tract, such as constipation, during aging. The motility alterations are intimately linked with its innervations. The goal of this study is to determine whether a program of exercise (running on the treadmill), during 6 months, has effects in the myenteric neurons (NADH- and NADPH-diaphorase stained neurons) in the colon of rats during aging. Male Wistar rats 6 months (adult) and 12 months (middle-aged) old were divided into 3 different groups: AS (adult sedentary), MS (middle-aged sedentary) and MT (middle-aged submitted to physical activity). The aging did not cause a decline significant (p>0.05) of the number of NADH-diaphorase stained neurons in sedentary rats (AS vs. MS group). In contrast, a decline of 31% was observed to NADPH-diaphorase stained neurons. Thus, animals that underwent physical activity (AS vs. MT group) rescued neurons from degeneration caused by aging (total number, density and profile of neurons did not change with age--NADH-diaphorase method). On the other hand, physical activity augmented the decline of NADPH-diaphorase positive neurons (total number, density and profile of neurons decreased). Collectively, the results show that exercise inhibits age-related decline of myenteric neurons however, exercise augments the decline of neurons with inhibitory activity (nitric oxide) in the colon of the rats.

Benefits of caloric restriction in the myenteric neuronal plasticity in aging rats

Aging is a biologic process characterized by progressive damage of structures and functions of organic systems. In gastrointestinal tract, it can involve enteric nervous system, which plays an important role in digestion and absorption of nutrients, causing hastening of intestinal transit thus reducing its absorptive function. Caloric restriction has been used in several studies with the intention of delaying deleterious effects of aging. This study aimed to evaluate the effects of caloric restriction on myenteric neurons of ileum by aging in rats. 30 Wistar rats were grouped as follows: GI (animals aged 6 months fed with normal diet), GII (animals aged 18 months fed with normal diet) and GIII (animals aged 18 months subject to 31% of caloric restriction). The rats of the GI group were euthanized at 6 months of age and after experimental period of 12 months animals of the group GII and GIII were euthanized, the ileum of all groups were collected, measured and processed by NADPH-dp and Acetylcholinesterase. Quantitative analysis of neurons revealed that aging promotes the increasing of myenteric neurons NADPH-dp and reduces Acetylcholinesterase neuronal population. However, in the cellular profile area, were not observed significant differences between the groups. The caloric restriction has been efficient and can be used preventively because it minimizes quantitative changes associated with aging on ileum myenteric plexuses.

Light and Scanning Electron Microscopic Study of the Tongue in the Estuarine Dolphin (Sotalia guianensis van Bénéden, 1864)

The importance of the tongue during feeding, and the limited information on the tongue of most aquatic mammals led us to investigate its morphological aspects in sexually immature and mature Sotalia guianensis. Six tongues were measured and photo-documented after their removal from the oral cavity. The samples were divided into rostral, middle, and caudal regions, and examined using light microscopy and scanning electron microscopy (S.E.M.). Sotalia guianensis tongue presented lateral grooves from the apex to the middle portion, while the anterolateral region presented marginal papillae. Histological characteristics revealed the presence of a keratinized stratified epithelium, salivary glands in the middle and caudal portions of the tongue, and filiform papillae in the caudal region. S.E.M. images revealed the presence of filiform papillae and ducts of salivary glands in the middle and caudal portions of the tongue. We can conclude that the characteristics found in this study may reflect an adaptation to changes in diet after weaning.

Assessment of NADPH-diaphorase stained myenteric neurons of the jejunum of diabetic rats supplemented with ascorbic acid

Silverio S.M., Mari R.B., Clebis N.K., Scoz J.R., Germano R.M., Agreste F., Bombonato P.P. & Stabille S.R. 2008. Assessment of NADPH-diaphorase stained myenteric neurons of the jejunum of diabetic rats supplemented with ascorbic acid. Pesquisa Veterinaria Brasileira 28(2):95-102. Departamento de Ciencias Biologicas, UNIPAR, Campus-Paranavai, Av. Huberto Bruning 360, Jardim Santos Dumont, Paranavai, PR 87706-490, Brazil. E-mail: srstabille@wnet.com.br The relation between hyperglycemia and diabetic neuropathy has already been demonstrated in some studies. Among the theories proposed for its etiology the oxidative stress stands out. The performance of nitric oxide as a link between the metabolic and vascular neuropathogenic factors that triggers the diabetic neuropathy has already been put forward. This study aimed to assess the quantification and measurements of the cell body profile area (CBPA) of NADPH-diaphorase reactive (NADPH-dp) myenteric neurons of the jejunum of diabetic rats (induced by streptozotocin) supplemented with Ascorbic Acid (AA). These changes in the myenteric neurons seem to be related to the gastrointestinal disturbances observed in diabetes mellitus (DM). Twenty male Wistar rats (Rattus norvegicus) were distributed in 4 groups (n=5): controls (C), control supplemented (CS), diabetic (D), and diabetic suplemented (DS). DM was induced by estreptozotocin (50mg/ kg body wt). One week after the induction and confirmation of the DM (glycemia exam), animals of the groups CS and DS received 50mg of AA three times a week by gavage. After 90 days of experiment, the animals were anesthetized with lethal thiopental dose (40mg/kg) and the collected jejunum processed for the histochemistry NADPH-diaphorase technique. Whole-mount preparations were obtained for quantitative and morphometric analysis of the myenteric neurons. A quantity of jejunum neurons in the Group D (96±7.5) was not different (P>0.05) from Group DS (116±8.08), C (92±9.7), and CS (81±5.4), but in Group DS the quantity was higher (P<0.05) than in Group C and CS. The CBPA of neurons from Group D (189.50±2.68μm 2 ) and DS (195.92±3.75μm 2 ) were lower (P<0.05) than from Group C (225.13±4.37μm 2 ) and CS (210.23±3.15μm 2 ). The streptozotocin-induced DM did not change the jejunum-ileum area, the jejunum myenteric plexus space organization and the density of NADPH-dp neurons. The 50g AA-supplementation, three times a week, during 90 days, did not decrease hyperglycemia; however, it had a neuroprotective effect on the myenteric neurons, minimizing the increase on the CBPA of NADPH-dp neurons and increasing the amount of NADPD-dp neurons.

Mecanoreceptores da mucosa palatina de avestruz (Struthio camelus): estudo ao microscópio de luz

Herbst corpuscles of the palatine mucosa of ostrich were studied by light microscopy. The corpuscles are composed of an outer core, inner core and central nerve terminal. The outer core presents numerous lamellae, while the inner core shows compact structure of cytoplasm sheets. The corpuscles are elongate or oval in shape and are surrounded by bundles of collagen fibers. Each lamella is composed of a dense network of thick fibrils. The terminal axons are located along the axis and form a bulb terminal. The fibers of external core stained by Picrosirius and examined by polarized light microscopy revealed to be green in color like type I collagen fibers, and at the periphery is a large amount of collagen type III. The corpuscles are surrounded by flat cells and dense collagen fibers at the periphery.

Effects of ascorbic acid supplementation in ileum myenteric neurons of streptozotocin-induced diabetic rats

Silverio S.M., Mari R.B, Clebis N.K., Scoz J.R., Germano R.M., Major J.A.A., Bombonato P.P. & Stabille S.R. 2009. Effects of ascorbic acid supplementation in ileum myenteric neurons of streptozotocin-induced diabetic rats. Pesquisa Veterinaria