Distribution of serotonin-immunoreactive enterochromaffin cells in the gastrointestinal tract of the least shrew (Cryptotis parva) / Distribución de las células enterocromafines serotonina-inmunorreactiva del tracto gastrointestinal de la musaraña enana (Cryptotis parva)

Serotonin is an important neurotransmitter in the central (CNS) and peripheral (PNS) nervous systems. It is involved in a variety of physiological processes both in the gut and in the CNS. The present study examined the distribution of serotonin containing enterochromaffin cells in the gastrointestinal tract (GIT) of a vomit competent species, the least shrew. These cells were easily recognized by their globular granules stained with the H&E and serotonin immune-positive stain. The immunoreactive enterochromaffin cells (IERCs) were mainly confined to the basal portion of the glandular epithelium and were distributed throughout the shrew stomach, small and large intestine. None was found to be associated with the mucosal epithelial lining. Moreover, their distribution and count varied in different regions of the GIT suggesting specific functions for these regions. The highest concentration of IERCs was found in the colon followed by the Jejunum. Appreciable numbers of IERCs were found in the stomach especially at the esophageo-gastric junction. The gastric location of the IERCs was mainly in the basal portion of the gland. However, some IERCs were associated with the parietal cells of the stomach. Two types of IERCs were observed: One with globular secretory granules in their apical portion of the cytoplasm which were located within the glandular epithelial cells facing the glandular lumen which release their secretions into the lumen; and the second were basally located, facing the lamina propria of the mucosa. Their secretory granules were not distinct in shape, and are most probably paracrine in their mode of secretions...

La serotonina es un importante neurotransmisor del sistema nervioso central (SNC) y periférico (SNP). Está implicado en una variedad de procesos fisiológicos, tanto en el intestino y el SNC. El presente estudio examinó la distribución de la serotonina contenida en las células enterocromafines del tracto gastrointestinal (TGI) de una especie competente al vómito, la musaraña enana. Estas células se reconocen fácilmente por sus gránulos globulares teñidas con H-E y la inmuno-tinción positiva para serotonina. Las células enterocromafines inmunorreactivas (CEI) se limitan principalmente a la parte basal del epitelio glandular y se distribuyeron por todo el estómago, intestino delgado e intestino grueso de la musaraña. Ninguna célula se encontró asociada al revestimiento epitelial mucoso. Además, su distribución y el recuento varió en diferentes regiones del TGI sugiriendo funciones específicas de estas regiones. La mayor concentración de CEI se encuentran en el colon seguido por el yeyuno. Números apreciables de CEI se encontraron en el estómago, especialmente en la unión esofago-gástrica. La ubicación de las CEI gástricas fue principalmente en la porción basal de la glándula. Sin embargo, algunas CEI se asociaron con las células parietales del estómago. Dos tipos de CEI se observaron, una con gránulos secretores globulares en su porción apical del citoplasma que se encuentra dentro de las células epiteliales glandulares que enfrenta el lumen glandular que liberan sus secreciones en el lumen, y el segundo se encuentra basalmente, frente a la lámina propia de la mucosa. Sus gránulos secretores no fueron diferentes en forma, y probablemente son más paracrinas en su modo de secreción...

Morphoquantitative study of the submucous plexus (of Meissner) of the jejunum-ileum of young and old guinea pigs / Estudo morfoquantitativo do plexo submucoso (de Meissner) do jejuno-íleo de cobaias jovens e velhas

OBJECTIVE: To study the aging of submucous plexus of the small intestine (jejunum-ileum) of the guinea pigs from the quantitative, structural and ultrastructural perspective. METHOD: Chemical preparations of membrane of the jejunum-ileum of old and young animals with the use of light and electronic microscope. RESULTS: The ganglia of young animals presented between 1 and 56 neurons and the old animals presented from 1 to 30 neurons. The mean density of the ganglia by cm² in the young jejunum-ileum was of 551±36.89 and in the old one 413±11.86. The density of the neurons was 5011±291.11 neurons/cm² average in young animals and 2918±120.70 neurons/cm² in the old ones. The size of the neurons varied in both age groups. The collagen fibers in the ganglia of old animals they were condensed. Degenerated mitochondrias in the interior of the cell were frequent in the old animals. CONCLUSION: In submucous plexus of the jejunum-ileum there is a loss of 38 percent of the neurons with aging.

OBJETIVO: Estudar o envelhecimento do plexo submucoso do intestino delgado (jejuno-íleo) das cobaias do ponto de vista quantitativo, estrutural e ultra-estrutural. MÉTODO: Preparados de membrana do jejuno-íleo de animais jovens e velhos com a utilização de microscopia de luz e eletrônica. RESULTADOS: Os gânglios de animais jovens apresentaram entre 1 e 56 neurônios e os animais velhos apresentaram de 1 a 30 neurônios. A densidade média dos gânglios por cm² no jejuno-íleo jovem foi de 551±36,89 e no velho foi de 413±11,86. A densidade dos neurônios foi de 5011±291,11 neurônios/cm² em média nos animais jovens e 2918±120,70 neurônios/cm² nos velhos. O tamanho dos neurônios variou em ambos os grupos etários. As fibras colágenas nos gânglios de animais velhos estavam mais condensadas. Mitocôndrias degeneradas no interior da célula foram freqüentes nos animais velhos. CONCLUSÃO: No plexo submucoso do jejuno-íleo há uma perda de 38 por cento dos neurônios com o envelhecimento.

Effect of dietary arginine on the jejunal mucosa in indomethacin-induced intestinal injury: light and scanning electron microscopic study in male mice

The non-steroidal anti-inflammatory drug [NSAID] indomethacin causes, via its adverse effects, damage to the gastrointestinal mucosa of humans and experimental animals. The indomethacin-induced intestinal injury in mice jejunum is considered an experimental model of Crohn's disease, as one of the inflammatory bowel diseases [IBD's]. The semi-essential amino acid arginine, which is a precursor of nitric oxide, is proposed to promote gastrointestinal mucosal integrity. The present work aimed to study the possible protective role of dietary supplementation with arginine in ameliorating indomethacin-induced mucosal injury of mice jejunum. The present study was carried out on forty adult male mice which were divided into 4 equal groups; group I [negative control group] which received no treatment, group II [positive control]; mice received dietary L-arginine alone in a daily dose of 300 mg/Kg, group III [indomethacin group]; mice of this group received 2 consecutive subcutaneous injections of indomethacin in a dose of 7.5 mg/kg, 24 hours apart and group IV [arginine group]; in which arginine supplementation was provided 2 days before the administration of indomethacin, maintained during the administration and continued 3 days later till the end of the experiment. Mice of all groups were sacrificed by the end of the 7[th] day and specimens from the jejunum were dissected and processed for light and scanning electron microscopic examinations. Indomethacin-treated group exhibited jejunal mucosal injury. Light microscopic examination of this group, using H and E and toluidine blue- stained semithin sections showed distorted villi and sloughing of some of their apical parts with extrusion of many degenerated cells, intermingled with excess mucous. Some enterocytes appeared degenerated with loss of their regular arrangement, while the goblet cells appeared distended with excess mucous secretion. Increased cellular infiltration and edema of the villous core and in the lamina propria between the glands were noticed. Increased mucous secretion was also demonstrated by combined alcian blue-periodic acid Schiff reaction. Scanning electron microscope revealed alteration in the architecture of many villi which appeared short, blunt or with denuded surface and occasionally covered with membrane-like structure. The group of mice received arginine [group IV] revealed restoration of mucosal integrity in the form of regular villi with intact epithelial coverings including enterocytes and goblet cells. Some villi appeared shorter, while others showed partially denuded apical surface. Arginine evoked a remarkable cellular infiltration. Lymphocytes and macrophages were among the infiltrating cells and their roles were suggested to be vital in the healing process. Dietary L-arginine provided satisfactory protection against indomethacin-induced mucosal injury in mice, most probably via its role as a nitric oxide donor. So supplementation with dietary arginine is recommended

role of green tea on strvation induced morphological changes in jejunal villi of male albino rat: histological, histochemical and scanning electron microscopic study

Green Tea is a naturally occurring compound. It is recognized as a very powerful antioxidant, anti inflammatory arid anti carcinogenic agent. The present work was done to investigate the role of green tea administration on morphological changes of the jejunal villi that might occur after starvation. Twenty male albino rats were used and divided into 4 equal groups, Group I [control rats]. Group II [starved rats for 7 day's], GroupIII [green tea treated rats for 7 days after 7 days of starvation,] and Group IV [recovered rats that were refed for 7 days after 7 days of starvation]. Animals were sacrificed at the end of the experiment. Jejunal villi of the starved rats were apparently thickened. There was significant increase in the meals villas thickness and a significant decrease in the mean height of the surface columnar cells as compared to that of' the control group. Tire core of the villi showed edema and cellular infiltration. There was a weak PAS positive reaction at the brush border of the columnar cells and the mean number 0/goblet ceils/villus was significantly decreased as compared to that of tire control group. with scanning electron microscope, starved rats showed loss of the microvilli at the apex of some of the villi. Poorly developed goblet cells were also observed. All these changes were improved and almost returned to normal in the green tea treated rats [group III,]. While in recovered rats [group IV] the improvement of starvation induced morphological changes of tire jejunal villi was minimum. So, it was concluded that the green tea administration could Improve and accelerate tire intestinal response to refeeding after starvation

Effect of early weaning on the jejunal villi of male albino rat. Histological, histochemical and scanning electron microscopic study

Although early weaning is common in the developing countries, yet its effects on the intestinal cells development are not well established. Thirty two male albino rats were used in the current study to investigate the effects of early weaning on the jejunal villi. Animals were divided into 4 equal groups. A control group [weaned on the day 21 after birth] and three experimental groups, that were weaned on day [10], [14] and [18 days and 9 hours] after birth respectively. Animals of all groups were sacrificed on the day 22 of birth. Early weaning in the present study demonstrated necrotic areas on the surface of the villi, reduction in the villous height, vacuolation and apparent hyperplasia of the surface colummar cells which appeared to be separated from each other at many sites. There were areas of loss of the brush border of the surface columnar cells. The core of the villi showed mononuclear cellular infiltration, congested blood capillaries and edema. There was increase in the mean number of intraepithelial lymphocytes [IELs] and reduction in time mean number of goblet cells/ villas. The intensity of alkaline phosphiatase enzyme reaction was reduced. All the previous changes were markedly observed when animals were weaned at early ages. In group IV, the jejunal villi showed nearly the same appearance as that of the control group. In conclusion, early weaning resulted in harmfull effects on the jejunial villi. The only safe early weaning was observed in group IV animals that were left to suckle for 18 days amid 9 hours which equals 7/8 of the full period of suckling in rat. This coincided with what was mentioned in the holy Quran concerning human beings where the longest mentioned period of suckling was 24 months amid the shortest period was 21 months which equals 7/8 of the longest period

Histological and immunohistochemical study on the effect of pregnancy and lactation on the jejunal mucosa of albino rat

This study was carried out to investigate the effect of pregnancy and lactation on the structure of jejunal mucosa. Fifteen adult female albino rats were used in this study. They were classified into three groups of five animals each. Group I: included virgin rats, which act as control. Group II: comprised pregnant rats at the third week of pregnancy. Group III consisted of lactating rats at the third week of lactation. All the animals were decapitated and jejunal specimens were taken and processed for histological, immunohistochemical and electron microscopic study. Morphometric study was also done and the obtained results were statistically analyzed. The results of the present study revealed that villus height increased during pregnancy and was maximum at lactation. The surface area of the enterocytes along the villi was significantly increased during pregnancy while their number was significantly increased during lactation. Immunohistochemical staining of proliferating cell nuclear antigen [PCNA] of cells in the crypt region showed a significant decrease in number of PCNA positive cells during pregnancy and a significant increase in their number during lactation. Electron microscopic results showed a significant increase in the microvillus height in lactating rats. Hypertrophy of the mitochondria and proliferation of rER were also evident during pregnancy and lactation. It is concluded that pregnancy and lactation induced morphological changes in the jejunal mucosa. These changes were accompanied by a decrease in cell turn over and a longer residence time of enterocytes during pregnancy

Microscopical study on the effect of starvation and refeeding on jejunum of adult male albino rat

The small intestine undergoes functional changes when food is withhold. To explore these changes, jejunal segments from the starved and refed adult male albino rats were investigated. After 3 days of starvation, atrophy of the villi and crypts was noticed. There was a significant decrease in the height of the villi of the starved animals. There was a discontinuity of the epithelium at the tip of some villi with exposure of the underlying connective tissue. The remaining columnar epithelial cells of the villus tip showed decrease in their height and their nuclei were small and deeply stained. There was a significant decrease in the number of goblet cells and also in the height of the columnar cells at the mid villus region of the starved animals compared with the control group. Histochemical study revealed decrease activity of alkaline phosphatase enzyme at the brush border of columnar absorptive cells of the starved animals. Scanning electron microscopic study revealed an apparent decrease in the height of the villi of the starved animals. In some areas, the villi were absent. Decrease in thickness of the villi was also noticed. Some villi of the starved animals were disorganized others showed destruction of their tips. The columnar absorptive cells showed shortening of their microvilli. In some areas the microvilli were lost from the surface. The goblet cells were depleted from their mucous granules. On the surface of some villi, there was total disappearance of the goblet cells. The above mentioned changes started to be normal on resumption of food intake after starvation. They might need more time to reach the control levels

Ultrastructural study of enteropathogenic Escherichia coli Olllab: H2 infection in an infant with acute diarrhea

Escherichia coli enteropatogênica clássica é o mais importante agente etiológico como causa de diarréia aguda nos países subdesenvolvidos, especialmente nos lactentes menores de uma ano de idade. As cepas de Escherichia coli enteropatogênica sao capazes de provocar profundas alteraçoes no citoesqueleto do enterócito, as quais sao denominadas aderência e apagamento das microvilosidades do enterócito, as quais sao denominadas aderência e apagamento das microvilosidades, associadas à formaçao de pedestais. Descreve-se uma cepa de Escherichia coli enteropatogênica 0111ab:H2 isolada das fezes de um lactente com diarréia aguda, no 11§ dia de doença, a qual provocou lesoes de aderência e apagamento das microvilosidades do enterócito e inclusive penetrou no interior do citoplasma do mesmo, assim como invadiu células HeLa em cultura de tecido in vitro e da mesma forma no teste da alça ileal ligada de coelho in vivo, todas as lesoes detectadas em estudo ultra-estrutural. Esta observaçao demonstra que lesoes graves da mucosa do intestino delgado causadas por uma cepa de Escherichia coli enteropatogênica 0111ab:H2 podem ocorrer ainda em um estágio precoce da infecçao entérica.

Jejunal absorption of trypsin in rat and guinea pig

Gut absorption is one of the first requirements for the study of the mechanism of a possible anti-inflammatory action of proteases, such as orally administered trypsin. Porcine trypsin absorption was studied in isolated jejunal loops of rats (female Holtzman and male Wistar) and guinea pig (males) by open-loop perfusion. Trypsin was dissolved in Tyrode solution and the solution perfused at a rate of 0.5 ml/min, at 37§C. Trypsin activity, total protein, and sodium and potassium concentrations were assayed in the jejunal effluent; the values were unchanged throughout the experiments, which lasted 45 to 120 min. Using a high sensitivity ELISA (i.e. pg/ml), trypsin absorption could be demonstrated by determination of the enzyme in the mesenteric venous blood (samples of 0.5 ml); the enzyme concentration increased with time of perfusion. The linear range-specificity for intact trypsin varied from 1 to 500 ng/well. In this assay polyclonal antibodies prepared against trypsin-TLCK were utilized. Whereas trypsin concentration in the perfused lumen was practically constant at 0.12 mg/ml, the concentration of absorbed trypsin in mesenteric vein blood increased from about 100 ng/ml at time zero to 1.8 µg/ml, after 45 min of perfusion. Histological and ultrastructural examination of the jejunal mucosa before and after perfusion revealed that the brush-border, basal membrane, and junctional complexes were fully preserved, thus eliminating the possibility that trypsin might have destroyed the structures, thereby reaching the blood circulation. The present data indicate that µg quantities of trypsin were absorbed by the isolated jejunal loop of the rat

Enteropatia ambiental: estudo ultra-estrutural da mucosa jejunal de criancas assintomaticas / Ambiental intestinal diseases: ultrastructure of the jejunum mucosa of asymptomatic children

Alteracoes morfologicas e funcionais do intestino delgadotem sido descrita em criancas que vivem em ambientes desfavoraveis, mesmo naquelas assintomaticas. Nete trabalho analisamos a ultra-estrutura da mucosa jejunal de criancas portadoras de enteropatia ambiental assintomatica. Omaterial de biopsia do intestino delgado estruturado foi procedente de 28 criancas, de ambos os sexos, com 2 a 12 meses de idade, e sem manifestacao gastrointestinal, portadoras de enteropatia ambiental assintomatica. A observacao ultra-estrutural foi realizada em um microscopio eletronico LM-9 Zeiss e alteracoes de intensidade variavel foram observadas em 19 (67,8//) pacientes: alteracoes das microvilosidades, tais como encurtamento, alargamento, fusao, formacao de tufos, reducao do numero emesmo ausencia das mesmas, foram observadas em 12 (63,1//); aumento do numero de lisossomos e corpos multivesiculares foram encontrados em 6 (31,5//) e 5 (26,3//) pacientes, respectivamente. As alteracoes ultra-estruturais observadas nestas criancas assintomaticas podem resultar no comprometimento da funcao digestivo-absortiva, muito provavelmente como decorrencia das altas taxas de contaminacao ambiental

Estudo morfológico da mucosa de um segmento de colo distal interposto entre cotos de intestino delgado após ressecçäo de oitenta por cento de seu comprimento: estudo experimental, com microscopia eletrônica de varredura, em ratas / Morphological study of the mucosa of a segment of the distal colon interposed between stumps of the small intestine after resection of 80 percent of its length: experimental study, with scanning electron microscopy, in female rats

O objetivo deste trabalho foi verificar em estudo com microscopia eletrônica de varredura, quais as eventuais alteraçöes morfológicas ocorridas na mucosa do intestino, seguindo o modelo experimental sobre a adaptaçäo do colo distal interposto entre cotos de intestino delgado após ressecçäo de oitenta por cento de seu comprimento, em ratos com noventa dias de observaçäo. Foram selecionados segmentos de jejuno, íleo, colo normal de cinco animais de controle e segmentos de jejuno a montante e íleo a jusante do colo interposto e do próprio colo interposto em cinco animais operados. Os resultados mostraram que ocorre um aumento de celularidade em todos os segmentos do grupo operado, com aumento das dimensöes das vilosidades no delgado. No segmento de colo interposto o aumento de celularidade leva alteraçöes do padräo morfológico em relaçäo ao normal, com modificaçöes dos óstios das criptas intestinais, modificaçöes nas características da camada de muco do colo e principalmente surgem formaçöes verrucosas na camada epitelial como projeçöes celulares ou brotos celulares. Embora a camada epitelial do colo interposto sofra modificaçöes, elas porém näo propiciam dados suficientes para denominá-las como "delgadizaçäo"