Functional morphology of the tongue of snake Bothrops jararaca (Reptilia: Squamata)

The tongue has a series of functions that can be related to feeding, such as transporting food to the back of the mouth, sensory function and capturing prey. The tongue of the reptiles has great morphological and functional variations between orders. This study aimed to described the morphological characteristics of the tongue of the snake Bothrops jararaca, relating them to the habitat and eating habits of this species. This work used five adult animals which were collected in the municipality of Viçosa, in the Zona da Mata Mineira region. The animals were euthanized, with anesthetic overdose, for the removal of the tongue, which was used for histological processing and scanning electron microscopy. The tongue had stratified epithelium with an extensive degree of keratinization and pigmentation. It was shown to be strongly muscular, innervated and vascularized. Keratinization and pigmentation is an important protection mechanism, due to the protrability of this organ, which is exposed to the environment to capture odors and locate prey. Mucous secretion was present as an important tool for lubrication and protection of the lingual lining. The tongue of the B. jararaca has no papillae and taste buds, being its function strictly olfactory, in association with the vomeronasal organ.Asociación Herpetológica Argentin

Functional morphology of the tongue of lizard Salvator merianae (Reptilia: Squamata)

The reptilian tongue has morphological and functional variations according to the feeding mechanisms and habitat of the species. This study aimed to understand the morphofunctional characteristics of the tongue of the lizard Salvator merianae, through anatomical, histological and scanning electron microscopy analyses. This study involves five adult animals, which were collected in the municipality of Viçosa, Minas Gerais, from Brasil. The tongue of S. merianae was protractile and bifid, important to drive molecules from the environment to the vomeronasal organ and thus identify odors and locate prey, besides being strongly muscular and with keratinized and pigmented stratified epithelium for protection. Mucous secretion was present as an important tool for lubrication and protection in view of the protrability of the tongue and the great presence of bacteria. Morphological specialization of the S. merianae tongue reflect its direct participation in food assimilation, with squamiform papillae for the mechanical function of maintaining prey in the oral cavity and contributing to swallowing. Taste buds were not found, which excludes the tongue participation in the taste, although it has olfactory sensory function in association with the vomeronasal organ.Asociación Herpetológica Argentin

Identification of enteroendocrine cells of Tropidurus torquatus and Salvator merianae (Squamata: Lacertilia)

The Squamata lizards Tropiduros torquatus and Salvator merianae are omnivores with different diets and foraging strategies, which requires adequate physiological responses of enteroendocrine cells, since they control digestive events, gastrointestinal epithelium renewal, metabolism and food intake. Thus, we aim to describe the distribution and frequency of enteroendocrine cells in the digestive tract of these two lizard’s species. Five individuals of each species were collected, euthanized and the digestive organs removed. Histological sections were submitted to the techniques of Grimelius for argyrophilic cells and Masson-Fontana for argentaffin cells. Both endocrine cells were found in the lining and glandular epithelium, with a pyramidal, oval, rounded, or elongated shape. Argyrophilic cells were observed in both species, predominantly in the stomach, but absent in the cranial esophagus. Argentaffin cells were distributed in almost the entire digestive tract but absent in the cranial portion of the esophagus and small intestine in both species, and with high frequency in the T. torquatus pyloric region. The absence of argentaffin cells in the cranial portion of the small intestine is intriguing and may reveal greater neural control over certain secretomotor functions involving this segment. We concluded that the inter-specific and inter-regional variations in the distribution and frequency of these cells may reflect the regulatory functions and mechanisms of each organ, taking also into account the oscillations of the food and nutritional status of animals in the wild.Os lagartos Squamata Tropiduros torquatus e Salvator merianae são onívoros com diferentes dietas e estratégias de forrageamento, o que requer respostas fisiológicas adequadas de células enteroendócrinas, uma vez que estas controlam os eventos digestivos, a renovação do epitélio gastrointestinal, o metabolismo e a ingestão alimentar. Portanto, pretendemos descrever a distribuição e frequência de células enteroendócrinas no trato digestivo destas duas espécies de lagartos. Foram coletados cinco indivíduos de cada espécie, eutanasiados e os órgãos digestivos removidos. Seções histológicas foram submetidas às técnicas de Grimelius para células argirófilas e Masson-Fontana para células argentafins. Ambas as células endócrinas foram encontradas no epitélio de revestimento e glandular, com formatos piramidal, oval, arredondado ou alongado. Células argirófilas foram observadas em ambas as espécies, predominantemente no estômago, mas ausentes no esôfago craniano. As células argentafins estiveram distribuídas em quase todo o trato digestivo, mas ausentes na porção cranial do esôfago e intestino delgado em ambas as espécies, e com alta frequência na região pilórica de T. torquatus. A predominância das células endócrinas no estômago pode estar relacionada, por exemplo, à maior permanência do alimento neste órgão, ao contrário do esôfago. A ausência de células argentafins na porção cranial do intestino delgado é intrigante e pode revelar maior controle neural sobre certas funções secretomotoras envolvendo este segmento. Nós concluímos que as variações inter-específicas e interregionais na distribuição e frequência destas células podem refletir as funções e mecanismos regulatórios de cada órgão, levando-se também em conta as oscilações do estado alimentar e nutricional dos animais na natureza.Asociación Herpetológica Argentin

Hystometric evaluation of nickel chronic exposure effects on large instestine of adult Wistar male rats

The ingestion of considerable amounts of water or food contaminated with nickel can be very toxic. The present work was conducted aiming to evaluate the effects of nickel exposures on ascending colon of adult Wistar male rats at hystometric level. We used 12 animals that were divided in a control (ingested uncontaminated water) and a nickel-contaminated (i.e., 25 mg de nickel/L of water) groups. Nickel chloride was offered in declorinated water and the experiment had a 56 days exposure period. A portion of the ascending colon was removed of the animals and subjected to hystological labelling processes using blue toluidin (for general hystometric description), Alcian Blue (AB, for acid mucins) and periodic acid-Schiff (PAS) technique (for neutral mucins). The potential differences between groups were desgined by applying the Whitney test and t test (p < 0.05). The crypts were smaller for the nickel-contaminated group, even though these organism exhibited broader and higher crypts. Nickel-contaminated animals exhibited a smaller amount of calyceform cells with AB and PAS positive reactions as well as a less mucus quantities when compared with nickel-uncontaminated animals. Such reductions on the amount of calyceform cells with AB and PAS positive reactions may be related wiht the shallower crypts, which possibly reduced the synthesis and secretion of mucins, compromissing the functional aspects (e.g., lubrification and intestinal mucosa protection) of the nickel-contaminated large intestines. Interestingly, the wider and higher crypts and higher epithelium collumn on the nickel-contaminated animals may represent a relevant trade-off for the intestinal mucosa protection

Morphological aspects of opossum (Didelphis aurita) pancreas during intramarsupial development

Abstract: This study reported the relevant morphological features found in the pancreas of the Brazilian opossum Didelphis aurita, a marsupial mammal, during its intramarsupial development. Newborns and young opossums removed from the pouch were divided into groups according to their average body length. The animals with few hours of intramarsupial life had visibly immature pancreas, due to the presence of early arrangement of endocrine and exocrine components. There was an only very large pancreatic duct, and blood vessels full of nucleated erythrocytes. In the individuals who were in the second third of intramarsupial development, the exocrine components were arranged in developing acini and endocrine cells were found arranged in early islets. The presence of connective tissue and the division of the organ into lobes became more evident at this stage. In the last third of the external gestation, we found better structured acini with relatively small lumens. The islets were well-organized, and the presence of connective tissue around them was the most evident. Morphometric analyses showed considerable variations in the proportion of pancreatic structural components between the stages of intramarsupial development, indicating that marsupial pancreas undergoes morphological modifications and grows during the period of external gestation. Keywords: Embryo; Marsupials; Digestive system; Organogenesis.

Zinc sulfate chronic exposure effects on large intestine of adult Wistar rats: a histological evaluation

Abstract: The present study aimed to investigate possible morphological changes in the large intestine of adult Wistar rats submitted to chronic exposure to zinc sulfate at different doses. The animals were divided into three groups: control, treated with 5mg and treated with 20mg of zinc sulfate. The experiment had 56 days of exposure period and after this period the animals were anesthetized and euthanized. After dissection, a fragment of the cranial portion of the ascending colon of each animal was removed, fixed in Karnovsky solution for 24 hours, dehydrated in a growing ethanolic series and included in glycolmethacrylate resin. In a manual microtome, slices of 3μm thickness were obtained and then, stained with blue toluidine, for tissue description and morphometric analysis. The samples were also also submitted to histochemical techniques: Periodic acid of Schiff (PAS) and Alcian Blue (pH 2.5), for marking neutral and acidic mucus producing cells, respectively. The morphological parameters analyzed were: crypt depth, intestinal epithelium height, and number of PAS-positive and Alcian Blue-positive goblet cells. A decrease of neutral mucin-producing cells number and an increase in the height of the intestinal epithelium were observed in the animals treated with 20 mg of zinc sulfate. These results indicate morphological changes in the large intestine due to chronic zinc exposure, indicating a stress condition. Keywords: Toxicity, Zinc, Intestine, Mammal, Morphology.

Anatomo-histological and neuroendocrine aspects of small intestine of the capybaras Hydrochoerus hydrochaeris Linnaeus, 1766 (Mammalia, Rodentia, Hydrochaeridae)

Foram analisados aspectos referentes à anatomia, histologia e morfometria do intestino delgado de capivaras adultas, obtendo-se dados sobre o comprimento e a capacidade volumétrica deste órgão e de seus segmentos, assim como características histológicas da sua parede, com ênfase no estudo das células enteroendócrinas e dos gânglios nervosos submucosos e mioentéricos. Para a análise histológica e morfométrica do intestino delgado foram empregadas técnicas de coloração Hematoxilina-Eosina, Alcian Blue - Ácido Periódico de Schiff, Grimelius, Masson Fontana modificada e Peroxidase anti-peroxidase com soro monoclonal anti-serotonina. Dentre os resultados anatômicos foi verificado que o intestino delgado da capivara é cerca de cinco vezes maior que o comprimento corporal e que a sua capacidade volumétrica representa 6,7% do peso corporal; dentre os resultados histológicos foram observados: pregas em espiral, espessas e ramificadas, ao longo de todo o revestimento interno do intestino delgado; vilos com formas e tamanhos variados na mucosa do intestino delgado; borda estriada espessa; presença de glândulas de Brunner na submucosa e na região basal da mucosa, restritas à porção cranial do duodeno, ricas em glicoconjugados ácidos e neutros; menor frequência de células caliciformes no duodeno, aumentando caudalmente; células de Paneth na base das criptas; células endócrinas argirófilas, argentafins e imunorreativas à serotonina em todos os segmentos do intestino delgado, abundantes na região das criptas e mais freqüentes no duodeno; gânglios nervosos submucosos e mioentéricos desenvolvidos, sendo maiores e mais frequentes os mioentéricos.Anatomical, histological and morphometric aspects of the small intestine of adult capybaras were analyzed, being obtained data on the length and the volumetric capacity of this organ and of its segments, as wel1 as histological characteristics of its wal1, with emphasis in the study of the enteroendocrine cel1s and of the submucosal and myenteric nervous ganglions. For the histological and morphometric analysis of the small intestine were used the coloration techniques: Hematoxylin-Eosin, Blue Alcian - Periodic Acid Schiff; Grimelius, modified Masson Fontana and Peroxidase anti-peroxidase with anti-serotomn monoclonal sore. Among the anatomical results was verified that the small intestine of the capybara is about five times longer than the corporallength and that its volumetric capacity represents 6,7% of the corporal weight; among the histological results were observed: pleats in spiral, thick and ramified, along the whole intemal coating of the smal1 intestine; vil1us with forms and sizes varied; thick brush-border; presence of Briinner' s glands in the submucosal layer and in the basal area of the mucosallayer, restricted to the cranial portion of the duodenum and rich in acid and neutral glicoconjugates; smaller frequency of goblet cel1s in the duodenum, increasing caudal1y; Paneth's cel1s in the base of the crypts; argyrophil, argentaffin and serotonin immunoreactive endocrine cel1s in all the segments of the small intestine, abundant in the area of the crypts and more frequent in the duodenum; submucous and myenteric nervous ganglia developed, being larger and more frequent the myenteric ganglions.Universidade Federal de Viços

Morphology of the alimentary canal of the gecko Hemidactylus mabouia (Moreau de Jonnès, 1818) (Squamata: Gekkonidae)

Hemidactylus mabouia é a espécie de lagartixa mais amplamente distribuída no Brasil, sendo comum em ambientes antrópicos, o que torna fácil seu uso como modelo para estudo dos répteis. Assim, visando descrever morfologicamente o tubo digestivo de H. mabouia, foram utilizados 17 exemplares adultos, sendo coletados fragmentos do esôfago, da transição esôfago-gástrica, do estômago e dos intestinos delgado e grosso, que foram processados conforme métodos rotineiros para análises anatômica, histológica, histoquímica e ultra-estrutural. Secções histológicas foram coradas com azul de toluidina ou submetidas a técnicas para detecção de glicoconjugados, proteínas, atividade da fosfatase alcalina, mitocôncrias e células endócrinas argirófilas e argentafins. O esôfago de H. mabouia é um órgão tubular retilíneo, com a porção cranial mais dilatada, o que facilita a deglutição de presas inteiras e concorre para a rápida desobstrução da cavidade bucofaringeana. O estômago tem forma de J , com uma extensa região fúndica, que pode ser subdividida em fúndica oral e fúndica aboral, e uma curta região pilórica. A presença de macrófagos na superfície gástrica constitui fato singular e reflete a necessidade de defesa no lúmen. Como o dos demais répteis carnívoros, o intestino de H. mabouia é curto, sendo o intestino delgado mais longo e convoluto que o intestino grosso, que possui um cólon bastante dilatado seguido por um reto curto. O epitélio de revestimento esofágico é pseudo- estratificado ciliado com células secretoras de mucinas ácidas e neutras; na transição esôfagogástrica há mistura deste tipo epitelial com o epitélio simples prismático mucossecretor de mucinas predominantemente neutras; no estômago é simples prismático mucossecretor de mucinas neutras; no intestino delgado é simples prismático com células absortivas e células mucossecretoras de mucinas ácidas e neutras; no intestino grosso as células absortivas são escassas, sem borda estriada ou com borda muito reduzida, e as células mucossecretoras são abundantes. No esôfago, a lâmina própria é delgada e aglandular; na transição esôfago-gástrica se torna espessa e preenchida por glândulas acinosas simples ramificadas, com células mucossecretoras de mucinas neutras e células zimogênicas produtoras de pepsinogênio. Essas glândulas multicelulares não foram observadas em vários répteis, mas foram descritas em muitos anfíbios anuros, o que pode estar relacionado com o hábito alimentar desses animais. No estômago, a região fúndica oral apresenta extensas glândulas túbulo-acinosas simples ramificadas, que se tornam menores, menos ramificadas e mais tubulares na fúndica aboral, e são tubulares simples e curtas na pilórica. As glândulas fúndicas possuem células mucossecretoras de mucinas neutras e células oxintopépticas, que diferem da fúndica oral para aboral em relação à densidade de grânulos de zimogênio e mitocôndrias, indicando a existência de um gradiente de secreção de pepsinogênio e ácido clorídrico. As glândulas pilóricas possuem apenas células mucossecretoras de mucinas neutras e células endócrinas argirófilas e argentafins, que também foram observadas dispersas no epitélio de revestimento e nas glândulas de outros segmentos do tubo digestivo, exceto no esôfago. Curiosamente, células argentafins mas não argirófilas foram localizadas na transição esôfago-gástrica. No intestino não há vilosidades nem criptas de Lieberkühn.Hemidactylus mabouia is the gecko species more thoroughly distributed in Brazil, being common in anthropic atmospheres, what turns easy its use as model for study of the reptiles. Likewise, aiming at to describe morphologically the alimentary canal of H. mabouia, 17 adult specimens were used, being collected fragments of the esophagus, of the oesophagogastric transition, of the stomach and of the small and large intestines, that were processed according to routine methods for anatomical, histological, histochemical and ultra-structural analyses. Histological sections were stained with Toluidine Blue or submitted to techniques for identification of glycoconjugates, proteins, alkaline phosphatase activity, mitochondria and argyrophil and argentaffin endocrine cells. The esophagus of H. mabouia is a tubular straight- lined organ, with the cranial portion more dilated, what favours the ingestion of whole preys and contributes to a rapid clearance of the bucco-pharyngeal cavity. The stomach has "J" form, with a long fundic region, which can be subdivided in oral fundic and aboral fundic, and a short pyloric region. The presence of macrophages in the gastric surface constitutes singular fact and reflects the defense need against invader microorganisms. As the one of the other carnivorous reptiles, the intestine of H. mabouia is short, being the small intestine more long and convoluted that the large intestine, that possesses a quite dilated colon followed for a short rectum. The oesophageal covering epithelium is pseudostratified with cells that secrete neutral and acid mucins; at the oesophagogastric transition there is a mixture of this epithelium with mucussecreting prismatic simple epithelium, whose cells secrete neutral mucins predominantly; in the stomach it is prismatic simple secreting neutral mucins; in the small intestine it is prismatic simple with absorptive cells and mucous cells secreting acid and neutral mucins; in the large intestine the absorptive cells are scarce, without brush border or with very short brush border, and the mucus-secreting cells are abundant. In the esophagus, the lamina propria is thin and aglandular; in the esophagus-gastric transition it becomes thick and filled by branched simple acinous glands, with mucous cells secreting neutral mucins and zymogenic cells producing of pepsinogen. Those multicellular glands were not observed in several reptiles, but they were described in many anuran amphibians, what can be related with the food habit of those animals. In the stomach, the oral fundic region presents long tubularacinous ramified simple glands, that become smaller, less ramified and more tubular in the aboral fundic region, and they are short tubular simple in the pyloric region. The fundic glands possess mucous cells secreting neutral mucins and oxynticopeptic cells, which differ of the oral fundic for aboral fundic in relation to the density of zymogen granules and mitochondria, indicating the existence of a secretion gradient of pepsinogen and hydrochloric acid. The pyloric glands just possess mucous cells secreting neutral mucins and argyrophil and argentaffin endocrine cells, which were also observed dispersed in the coating epithelium and in the glands of other segments of the alimentary canal, except in the esophagus. Surprisingly, argentaffin but non argyrophil cells were located in the oesophagogastric transition. In the intestine there are neither villi nor Lieberkühn crypts.Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

Hystometric evaluation of nickel chronic exposure effects on large instestine of adult Wistar male rats

The ingestion of considerable amounts of water or food contaminated with nickel can be very toxic. The present work was conducted aiming to evaluate the effects of nickel exposures on ascending colon of adult Wistar male rats at hystometric level. We used 12 animals that were divided in a control (ingested uncontaminated water) and a nickel-contaminated (i.e., 25 mg de nickel/L of water) groups. Nickel chloride was offered in declorinated water and the experiment had a 56 days exposure period. A portion of the ascending colon was removed of the animals and subjected to hystological labelling processes using blue toluidin (for general hystometric description), Alcian Blue (AB, for acid mucins) and periodic acid-Schiff (PAS) technique (for neutral mucins). The potential differences between groups were desgined by applying the Whitney test and t test (p < 0.05). The crypts were smaller for the nickel-contaminated group, even though these organism exhibited broader and higher crypts. Nickel-contaminated animals exhibited a smaller amount of calyceform cells with AB and PAS positive reactions as well as a less mucus quantities when compared with nickel-uncontaminated animals. Such reductions on the amount of calyceform cells with AB and PAS positive reactions may be related wiht the shallower crypts, which possibly reduced the synthesis and secretion of mucins, compromissing the functional aspects (e.g., lubrification and intestinal mucosa protection) of the nickel-contaminated large intestines. Interestingly, the wider and higher crypts and higher epithelium collumn on the nickel-contaminated animals may represent a relevant trade-off for the intestinal mucosa protection.La ingestión de cantidades considerables de agua o alimentos contaminados con níquel puede ser muy tóxica. El presente trabajo se realizó con el objetivo de evaluar los efectos de las exposiciones al níquel en el colon ascendente de ratas macho Wistar adultas a nivel histométrico. Utilizamos 12 animales que se dividieron en un control (agua ingerida no contaminada) y un grupo contaminado con níquel (es decir, 25 mg de níquel / L de agua). Se ofreció cloruro de níquel en agua desclorinada y el experimento tuvo un período de exposición de 56 días. Una parte del colon ascendente se retiró de los animales y se sometió a procesos de marcaje histológico usando toluidina azul (para descripción histométrica general), azul de Alcian (AB, para mucinas ácidas) y la técnica periódica de ácido-Schiff (PAS) (para mucinas neutras). Las diferencias potenciales entre los grupos se diseñaron mediante la aplicación de la prueba de Whitney y la prueba t (p <0.05). Las criptas eran más pequeñas para el grupo contaminado con níquel, a pesar de que estos organismos exhibían criptas más amplias y más altas. Los animales contaminados con níquel exhibieron una menor cantidad de células caliceiformes con reacciones positivas AB y PAS, así como una menor cantidad de moco en comparación con los animales no contaminados con níquel. Dichas reducciones en la cantidad de células caliceiformes con reacciones positivas AB y PAS pueden estar relacionadas con las criptas menos profundas, lo que posiblemente redujo la síntesis y secreción de mucinas, comprometiendo los aspectos funcionales (p. Ej., lubricación y protección de la mucosa intestinal) del intestino grueso contaminado con níquel. Curiosamente, las criptas más anchas y más altas y la columna de epitelio más alta en los animales contaminados con níquel pueden representar una compensación relevante para la protección de la mucosa intestinal