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...

The radioprotective effects of the hexane and ethyl acetate extracts of Callophyllis japonica in mice that undergo whole body irradiation

The radioprotective activity of extracts from the red seaweed Callophyllis (C.) japonica was investigated in mice that underwent whole-body exposure to gamma radiation. A methanol extract of C. japonica and its fractions [hexane, ethyl acetate (EtOAc), butanol and the remaining H(2)O] were used. Each fraction (100 mg/kg body weight) was administered intraperitoneally (i.p.) 2 times into the BALB/c mice, once at 1 and once at 24 h before exposure to 9 Gray (Gy) of gamma radiation. Pre-irradiation administration of the hexane and EtOAc fractions saved the mice, with their survival rates being greater than 80% at 30 days post-irradiation; the mice that were pretreated with the other fractions showed survival rates lower than 20% over the same time period. To examine the effect of each C. japonica fraction on the survival of intestinal and bone marrow stem cells, the number of intestinal crypts and bone marrow cells in the gamma-irradiated mice were examined. Pre-treatment of mice (i.p., 100 mg/kg body weight at 1 and 24 h before irradiation) with the hexane or EtOAc fraction prior to 6-Gy irradiation significantly protected the number of jejunal crypts and bone marrow cells at 9 days after irradiation. These findings suggest that certain extracts from C. japonica, when they are administered prior to irradiation, play an important role in the survival of irradiated mice, and this is possibly due to the extracts protecting the hematopoietic cells and intestinal stem cells against gamma irradiation.

A study of the effects of pinealectomy on intestinal cell proliferation in infant newborn rats

OBJETIVO: Estudar a taxa de proliferação celular no jejuno e nas células epiteliais das criptas do intestino grosso em ratos pinealectomizados imediatamente após o nascimento. MÉTODOS: 24 ratos machos Wistar foram divididos em dois grupos. Grupo agudo (n=12) e Grupo Crônico (n=12). Seis animais de cada grupo foram operados para remover-se a glândula pineal (Pinealectomia-PnX), e outros seis animais foram controle (sham pinealectomia-C). Os animais de ambos os grupos foram sacrificados 15 e 90 dias após a cirurgia, respectivamente. RESULTADOS: No grupo agudo, a pinealectomia dos ratos não causou alterações significativas na proliferação celular (PnX=58,77±1,77 e C=60,88±1,10 no cólon descendente / PnX=31,56±0,45 e C=31,73±0,47 no jejuno proximal) e na população celular de criptas (PnX=24,92±4,82 e C=23,60±2,48 no cólon descendente / PnX=39,92±3,49 e C=44,32±5,56 no jejuno proximal). Contudo, no grupo crônico houve aumento na proliferação celular das criptas no jejuno proximal (PnX=57,54±2,19 e C=47,19±7,3), e no cólon descendente (PnX=37,78±2,22 e C=17,92±2,28). CONCLUSAO: Como o aumento epitelial celular das criptas intestinais no grupo crônico pode ser avaliado como fator predeterminante da carcinogênese, faz-se necessário o conhecimento da interação entre esta glândula e este evento.

Mucosal mast cell-derived chondroitin sulphate levels in and worm expulsion from FcRgamma-knockout mice following oral challenge with Strongyloides venezuelensis

Mucosal mast cell-derived chondroitin sulphates (sulphated proteoglycans) were assayed in gut washings and homogenate of FcRgamma-knockout (KO) and wild-type (WT) C57BL/6 mice challenged with Strongyloides venezuelensis in order to assess their possible role in secondary immunity against enteric nematodes. Groups of immune KO and WT mice were challenged by oral gavage with 300 infective larvae (L3). Establishment of infection was assessed by daily faecal analysis to determine the number of eggs per gram of faeces (EPG) and by adult worm recovery on days 5 and 13 post challenge. Mucosal mast cell (MMC) counts were done on days 5 and 13 post challenge while MMC-derived chondroitin sulphates in gut washings (days 1 and 5) and homogenate (day 8) were assayed by high performance liquid chromatography (HPLC). Results showed that patent infection occurred in challenged KO but not WT mice despite significantly higher mastocytosis in jejunal sections of KO than WT mice (p<0.001). Similarly but against prediction, significantly higher concentration of MMC-derived chondroitin sulphates was observed in gut homogenate of KO than WT mice (p<0.05). In contrast, significantly higher concentration of chondroitin sulphates was observed in gut washings of WT than KO mice (p<0.05). These results suggest that MMC in KO mice failed to release sufficient amount of sulphated proteoglycans into the gut lumen as did the WT mice, which may have been part of the hostile environment that prevented the establishment in and eventual expulsion of adult S. venezuelensis from the gut of WT mice following challenge.

Cell proliferation and migration in the jejunum of suckling rats submitted to progressive fasting

Cell proliferation and migration in the intestinal crypts, and cell migration in the villus are controlled by different mechanisms in adult rats. In the present study, weanling rats and fasting rats were used to quantitatively study the correlation of cell cycle parameters and epithelial cell migration in crypts and intestinal villi. Eighteen-day-old rats received a single injection of tritiated thymidine[3H]T dR (23:00 h); half of the pups were submitted to fasting 5 h earlier. Cell proliferation was determined in radioautographs of jejunal crypts, on the basis of the labeling indices (LI) taken 1,8,13 and 19 h after [3H]TdR. The results showed that the labeling index did not differ 1 h or 19 h after [3H]TdR between the fed (38.7 percent or 48 percent) and fasting groups (34.6 percent or 50.4 percent). The modified method of grain count halving indicated that cell cycle time did not differ between fed (16.5 h) and fasting rats (17.8 h); the growth fraction, however, had lower values in fasting (59 percent) than in fed rats (77 percent). Cell migration in the crypt, estimated by the LI obtained for each cell position, did not change with treatment. As for the villi, the cell migration rate was significantly retarded by 3 cell positions (8 percent). These results suggest that the cell migration in the villi of weanling pups does not depend directly on the cell proliferation and migration in the intestinal crypt, but is directly affected by the absence of food in the lumen.

Efeito da fitohemaglutinina na proliferaçäo celular do epitélio do intestino delgado de ratos / Effect of phytohemagglutinins in cell proliferation of the epithelium of the small intestine of rats

Vinte ratos albinos, foram divididos em dois grupos de dez: grupo e, que recebeu dieta sólida contendo 4% de fitohemaglutinina (FHG) ativa e água "ad libitum" e grupo P controle pareado iso-calórico, que recebeu a mesma dieta sólida porém com fitohemaglutinina inativada pelo calor e água "ad livitum". Diariamente os animais foram pesados, as quantidades de raçäo e água foram anotados. No 14§ de experimento, os animais foram sacrificados e colhidos fragmentos de jejuno e íleo para estudo morfocinético. Os resultados mostraram que: a ingestäo hídrica foi semelhante em ambos os grupos estudados e o grupo E ganhou menos peso corporal do que o grupo P. As populaçöes de enterócitos das vilosidades jejunais do grupo E, foram menores em termos estatísticos quando comparadas ao grupo P, e o contrário se deu no íleo, onde o grupo E foi maior que o P. A altura da vilosidade do grupo E foi semelhante ao do grupo P, mas o íleo do grupo E foi maior do que o do grupo P. As profundidades, as populaçöes e as taxas de produçäo celular nas criptas jejunais do grupo E foram significativamente maiores que no grupo P. Concluindo, os achados no presente estudo fornecem evidências de que a ingestäo de fitohemaglutinina lesa a mucosa jejunal proxima, diminuindo a populaçäo celular da vilosidade e estimulando a hiperplasia da cripta, desenvolvendo adaptaçäo localizada. Este modelo adaptativo é semelhante ao que acontece na doença celíaca. Esta lesäo proximal estimula a hiperplasia da unidade cripta-vilosidade do epitéileal, desenvolvendo adaptaçäo à distância. Estas adaptaçöes aconteceram em animais que ingeriram fitohemaglutinina, mesmo na vigência de desnutriçäo multicarencial

Cuantificación de células conteniendo inmunoglobulinas A, G y M en mucosa yeyunal de niños / Quantification of cells countaining immunoglobulins, A, G and M in jejunal mucosa of children

Se estudió la mucosa yeyunal de 15 niños con edades comprendidas entre 6 horas y 9 años con el objeto de cuantificar los inmunocitos de clase A, G y M. Fueron utilizados métodos de inmunofluorescencia directa y la cuantificación fue obtenida a través del método de Aherne II. En los recién nacidos los hallazgos fueron cero de inmunocitos, pero en las demás edades las cifras mostraron variaciones de acuerdo con el tipo celular. Los inmunocitos A aumentaron progresivamente: a los 3 meses las cifras fueron 17,500; a los 11 meses, 51.500, a los 2 años 65.000 y a los 9 años 75.000 cel/mm3. Las cifras de inmunocitos IgM se mantuvieron comprendidas entre 10,000 y 14,000 desde la edad de 3 meses y 9 años, y en el mismo periodo la cifra de los inmunocitos IgG permanecieron muy próximas de 4,000 cel/mm3