Polysaccharides from Hemp Seed Protect against Cyclophosphamide-Induced Intestinal Oxidative Damage via Nrf2-Keap1 Signaling Pathway in Mice.

Hemp seed has been used as a traditional oriental medicine and health food in China for centuries. Polysaccharides from hemp seed (HSP) exhibit important properties of intestinal protection, but there are limited data on the specific underlying mechanism. The primary objective of this study was to investigate the protective effect of HSP on intestinal oxidative damage induced by cyclophosphamide (Cy) in mice. The results showed that pretreatment with HSP significantly increased the average daily gain, thymus index, spleen index, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activity in serum and ileal homogenate and significantly reduced malondialdehyde (MDA) content in ileal homogenate. In addition, the expression levels of SOD, GSH-Px, Nrf2, heme oxidase-1 (HO-1), and quinoneoxidoreductase-1 (NQO1) mRNA in ileal homogenate were significantly increased. Western blot results showed that HSP significantly upregulated the expression of Nrf2 protein and downregulated the expression of Keap1 protein in the ileum. Collectively, our findings indicated that HSP had protective effects on intestinal oxidative damage induced by Cy in mice, and its mechanism might be related to the activation of Nrf2-Keap1 signaling pathway.

Morphological alterations in the jejunal mucosa of aged rats and the possible protective role of green tea.

INTRODUCTION: Gastrointestinal disorders become more prevalent with ageing. This study is aimed to describe morphological changes that occur in the jejunal mucosa of male albino rats as a result of ageing and the protec-tive effect of green tea (GT) extract. MATERIAL AND METHODS: The experiment was performed on sixty rats: thirty young-adult (6-month old, body mass 200-220 g) and thirty old (24-month-old, body mass 220-260 g) animals. Each group was further divided into two subgroups (n = 15 each): control rats and GT-treated rats that received 1.5 mL (300 mg/kg/day) of GT extract for 14 weeks by oral gavage. Sections of the jejunum were stained with hematoxylin and eosin, periodic acid Schiff, toluidine blue and Mallory trichrome methods. The presence of proliferating cell nuclear antigen (PCNA)- and CD68-positive cells was evaluated by immunohistochemical staining. Ultrathin sections were prepared and examined by a transmission electron microscope (TEM). RESULTS: Jejunal sections of the old control rats showed distortion of submucosa and attenuated muscularis externa with decreased height of intestinal villi. The villi also showed partial loss of acidophilic brush border with wide spaces between enterocytes. Swollen, short, blunt or broad villi with abundant mononuclear cell infiltration of lamina propria and congested blood vessels were evident both by light and electron microscopy. The number of PCNA- and CD68-positive cells in jejunal mucosa of old rats was higher than in young rats. The activity of glutathione peroxidase (GPX) and total antioxidant capacity (TAC) in the mucosa of old control rats were lower, whereas malondialdehyde (MDA) levels were higher in the jejunal homogenates of old rats as compared to young control rats. Administration of GT extract protected the jejunal mucosa from age-related changes by restoring its histological structure. The treatment of old rats with GT extract significantly decreased MDA levels in the jejunum and increased TAC and GPX activity. CONCLUSIONS: The age-related changes of the morphology of rat jejunum could be ameliorated by prolonged supplementation of the green tea extract.

Interactive effects of temperature and dietary supplementation of arginine or guanidinoacetic acid on nutritional and physiological responses in male broiler chickens.

1. The aim of this experiment was to study the interactive effect of rearing temperature and dietary supplementation of arginine (Arg) or guanidinoacetic acid (GAA) on performance, gut morphology and ascites indices in broiler chickens raised under the same condition in the first 2 weeks and then reared under normal (23-26°C) or subnormal (17°C) ambient temperatures for the next 3 weeks. 2. This experiment was conducted as a split plot with 900 Ross 308 male broiler chicks that were allocated to two houses (as main plots); each consisted of 5 treatments (as sub-plots) with 6 replicates of 15 birds. The 5 diets were (1) control, (2) control + 0.60 g/kg GAA, (3) control + 1.20 g/kg GAA, (4) control + 0.86 g/kg Arg and (5) control + 1.72 g/kg Arg. 3. Feed intake (0-35 d) of birds fed on a diet containing 1.2 g GAA/kg and reared under normal temperature was reduced compared to control fed birds. Birds fed on a diet containing 1.72 g/kg Arg and reared under subnormal temperature had higher weight gain compared to those fed on control or GAA-added diets in overall study period. 4. Supplementation of diets with Arg alleviated the adverse effect of cold stress as reflected by reduction in blood haematocrit (41% vs. 37%), and right ventricle to total ventricle ratio (0.28 vs. 0.25) at 35 d of age. Addition of Arg to the diet of birds reared under cold stress resulted in a higher jejunal villus surface area compared to those fed on control or GAA-added diets. 5. Findings of this study revealed that Arg or GAA supplementation of diets did not affect performance of birds under normal temperatures, but Arg supplementation of the diet significantly alleviated the adverse effect of cold stress on performance, gut development and ascites syndrome. In addition, GAA supplementation at 1.2 g/kg improved jejunal villus surface area in birds raised under subnormal temperature.

Protective effect of Bu-Zhong-Yi-Qi decoction, the water extract of Chinese traditional herbal medicine, on 5-fluorouracil-induced intestinal mucositis in mice.

Intestinal mucositis is a serious toxic side effect of 5-fluorouracil (5-FU) treatment. Bu-Zhong-Yi-Qi decoction (BZYQD), a water extract of Chinese traditional herbal medicine, is widely used in chemotherapy in Asia as an alternative treatment to reduce the side effects of chemotherapy. However, the mechanism is unknown. To evaluate its mechanism, we investigated the effect of BZYQD on 5-FU-induced intestinal mucositis in mice, especially with regard to apoptosis in the intestinal mucosal epithelia. In the present study, mice were divided into three groups: control, 5-FU, and 5-FU + BZYQD. Mice in the 5-FU and 5-FU + BZYQD groups were administered 5-FU (100 mg/kg/day, intraperitoneally) for 6 days, and the mice in the latter group were given BZYQD (8 g/kg/day, intragastrically) beginning 4 days before 5-FU and continuing until the termination of the experiment. Loss in body weight and diarrhea during the 5-FU treatment were significantly attenuated by administration of BZYQD. The morphological signs of intestinal damage, including shortened villi height, crypt destruction, apoptosis, and necrosis, in intestinal mucosal epithelia were also reversed, accompanied by reduced neutrophil infiltration, nitrite levels, and inflammatory factors (tumor necrosis factor α and interleukin 1ß) and increased levels of reduced glutathione. These results suggest that BZYQD inhibits 5-FU-induced intestinal mucositis, and this effect may be due to the reduction in apoptosis and necrosis in intestinal mucosal epithelia via the suppression of inflammatory cytokine upregulation. In conclusion, inhibiting cytokine-mediated apoptosis or necrosis can be the molecular mechanism by which BZYQD reduces the gastrointestinal side effects of cancer chemotherapy.

Coated zinc oxide improves intestinal immunity function and regulates microbiota composition in weaned piglets.

The present study was conducted to test the hypothesis that low concentrations of coated ZnO, as a substitute for a high concentration of ZnO (2250 mg Zn/kg), could improve intestinal immunity function and regulate microbiota composition, thus alleviating the incidence of diarrhoea in weaned piglets. A total of eighty-four cross-bred piglets, weaned at an age of 28 (SEM 1) d, were allocated randomly, on the basis of average initial body weight (7·72 (SEM 0·65) kg), to seven treatment groups as follows: a 250 mg Zn (ZnO)/kg group (low Zn; LZ) and a 2250 mg Zn (ZnO)/kg group (high Zn; HZ) that were offered diets containing ZnO at 250 and 2250 mg Zn/kg, respectively; and five experimental groups in which coated ZnO was added at 250, 380, 570, 760 and 1140 mg Zn/kg basal diet, respectively. The trial lasted 2 weeks. The results indicated that, compared with LZ treatment, supplementation with coated ZnO at 380 or 570 mg Zn/kg reduced (P< 0·05) diarrhoea index, increased (P< 0·05) duodenal villus height and the ratio of villus height:crypt depth, up-regulated (P< 0·05) the gene expression of insulin-like growth factor 1, zonula occludens protein-1, occludin, IL-10 and transforming growth factor ß1, and elevated (P< 0·05) secretory IgA concentration in the jejunal mucosa. Microbiota richness and the Shannon diversity index were also decreased (P< 0·05). Furthermore, piglets in the group fed coated ZnO at 380 or 570 mg Zn/kg did not differ from those in the HZ-fed group in relation to the aforementioned parameters. Collectively, a low concentration of coated ZnO (380 or 570 mg Zn/kg) can alleviate the incidence of diarrhoea by promoting intestinal development, protecting the intestinal mucosal barrier from damage, stimulating the mucosal immune system and regulating the microbiota composition.

Influence of dietary inclusion of Bacillus licheniformis on laying performance, egg quality, antioxidant enzyme activities, and intestinal barrier function of laying hens.

This experiment was conducted to evaluate the effects of dietary inclusion of Bacillus licheniformis on laying performance, egg quality, antioxidant enzyme activities, and intestinal barrier function of laying hens. Hy-Line Variety W-36 hens (n = 540; 28 wk of age) were randomized into 6 groups, each group with 6 replications (n = 15). The control group received the basal diet formulated with maize and soybean meal. The treatment groups received the same basal diets supplemented with 0.01, 0.02, 0.03, 0.06, and 0.09% Bacillus licheniformis powder (2 × 10(10) cfu/g) for an 8-wk trial. The results showed that dietary supplementation with 0.01 and 0.03% B. licheniformis significantly increased egg production and egg mass. However, no significant differences were observed in egg weight, feed consumption, and feed conversion efficiency among the 6 groups. Supplementation with different levels of B. licheniformis was found to be effective in improvement of egg quality by increasing egg shell thickness and strength. Compared with control, d-lactate content, diamine oxidase activity, and adrenocorticotropic hormone level in serum decreased significantly, and the level of estradiol and follicle-stimulating hormone increased significantly in plasma of all the experimental groups. Dietary supplementation with B. licheniformis increased the intestinal villus height and reduced the crypt depth. In conclusion, dietary inclusion of B. licheniformis could improve laying performance and egg quality significantly in a dose-dependent manner by decreasing the stress response, upregulating the growth hormone, and improving intestinal health.

Chemical composition and biological value of spray dried porcine blood by-products and bone protein hydrolysate for young chickens.

The chemical composition of spray dried porcine blood by-products is characterised by wide variation in crude protein contents. In spray dried porcine blood plasma (SDBP) it varied between 670-780 g/kg, in spray dried blood cells (SDBC) between 830-930 g/kg, and in bone protein hydrolysate (BPH) in a range of 740-780 g/kg. Compared with fish meal, these feeds are poor in Met and Lys. Moreover, in BPH deep deficits of Met, Cys, Thr and other amino acids were found. The experiment comprised 7 dietary treatments: SDBP, SDBC, and BPH, each at an inclusion rate of 20 or 40 g/kg diet, plus a control. The addition of 20 or 40 g/kg of the analysed meals into feeds for very young chickens (1-28 d post hatch) significantly decreased the body weight (BW) of birds. Only the treatments with 40 g/kg of SDBP and SDBC showed no significant difference in BW as compared with the control. There were no significant differences between treatments and type of meal for feed intake, haematocrit and haemoglobin concentrations in blood. Addition of bone protein and blood cell meals to feed decreased the IgG concentration in blood and caused shortening of the femur and tibia bones. However, changes in the mineral composition of bones were not significantly affected by the type of meal used. The blood by-products, which are rich in microelements, improved retention of Ca and Cu only. In comparison to control chickens, significantly better accretion of these minerals was found in treatments containing 20 g/kg of SDBP or 40 g/kg of SDBC. Great variability in apparent ileal amino acid digestibility in chickens was determined. In this respect, some significant differences related to the type of meal fed were confirmed for Asp, Pro, Val, Tyr and His. In general, the apparent ileal digestibility of amino acids was about 2-3 percentage units better in chickens fed on diets containing the animal by products than in control birds.

A milk diet partly containing soy protein does not change growth but regulates jejunal proteins in young goats.

Soy protein is known to alter intestinal function and structure. We determined in young goats whether a diet partly containing soy protein differently affects intestinal morphology and the jejunal and hepatic proteome as compared with a milk diet. Fourteen male 2-wk-old White German dairy goat kids were fed comparable diets based on whole cow's milk in which 35% of the crude protein was casein (milk protein group; MP) or soy protein supplemented by indispensable AA (SPAA) for 34 d (n = 7/group). Body weight gain and food efficiency were not different. Jejunal and hepatic tissue was collected to determine intestinal morphology by microscopy and protein repertoire by 2-dimensional gel electrophoresis and mass spectrometry. Jejunal crypt depth was reduced and villus height to crypt depth ratio was higher in SPAA than in milk protein. Out of 131 proteins identified, 32 proteins were found to be differently expressed in both groups. In SPAA, down-regulated jejunal proteins were involved in processes related to cytoskeleton generation, protein, lipid, and energy metabolism. Downregulated hepatic proteins were related to glycolysis and Krebs cycle. Thirteen proteins were upregulated in SPAA. Among these, 2 hepatic proteins were related to carbohydrate breakdown. The other 11 jejunal proteins were involved in cytoskeleton assembly, proteolysis, and carbohydrate breakdown. In addition, glutathione-S-transferase was found to be upregulated in the medial jejunum. In conclusion, a SPAA diet as compared with a milk diet was related to changes in jejunal morphology and jejunal proteins relevant for protein turnover, energy metabolism, and cytoskeleton assembly with no apparent impact on animal BW gain.

Selective mineral elements concentration of the intestinal mucosa role of the lysosomes of duodenal enterocytes in the handling of mineral elements after intragastric administration.

Intragastric administration to rats of four soluble lanthanides cerium, lanthanum, europium, thulium and of three soluble elements of group IIIA aluminium, indium and gallium has been shown in previous studies. In this work two new rare earths gadolinium and terbium were studied using the same protocols and the same methods (transmission electron microscopy and ion microanalysis). among the previously studied elements, some of them were administered simultaneously on the one hand aluminium and indium, and on the other hand, lanthanum and cerium. These metals were looked for in intestinal mucosa, liver and kidney. The results showed: a) gadolinium and terbium were selectively concentrated in lysosomes of duodenal enterocytes, precipitated as non-soluble phosphate salts and eliminated with the cell's turn-over in less than 48 hr; b) Administered simultaneously, they precipitated in the same lysosome. c/ none of them was observed in the liver or kidney even with high dose. This study brings up to nine the number of elements forming a non-soluble phosphate salts, explaining their precipitation in lysosomes. None of them have a physiological role, two are toxic (aluminium and indium). This rapid intralysosomal concentration is an efficient mechanism which limits the diffusion of the foreign substances through the digestive barrier, then permits their elimination along with the cytoptose phenomenon in the intestinal lumen.

Piperine modulates permeability characteristics of intestine by inducing alterations in membrane dynamics: influence on brush border membrane fluidity, ultrastructure and enzyme kinetics.

Piperine (1-Piperoyl piperidine) is a major alkaloid of Piper nigrum Linn. and Piper longum Linn. It is shown to possess bioavailability-enhancing activity with various structurally and therapeutically diverse drugs. The mechanism of enhancing the bioavailability, is, however, not understood. We hypothesize that piperine's bioavailability-enhancing property may be attributed to increased absorption, which may be due to alteration in membrane lipid dynamics and change in the conformation of enzymes in the intestine. Results of membrane fluidity studies using an apolar fluorescent probe, pyrene (which measures the fluid properties of hydrocarbon core), showed an increase in intestinal brush border membrane (BBM) fluidity. Piperine also stimulated Leucine amino peptidase and Glycyl-glycine dipeptidase activity, due to the alteration in enzyme kinetics. This suggests that piperine could modulate the membrane dynamics due to its apolar nature by interacting with surrounding lipids and hydrophobic portions in the protein vicinity, which may decrease the tendency of membrane lipids to act as stearic constrains to enzyme proteins and thus modify enzyme conformation. Ultra structural studies with piperine showed an increase in microvilli length with a prominent increase in free ribosomes and ribosomes on the endoplasmic reticulum in enterocytes, suggesting that synthesis or turnover of cytoskeletal components or membrane proteins may be involved in the observed effect. In conclusion, it is suggested that piperine may be inducing alterations in membrane dynamics and permeation characteristics, along with induction in the synthesis of proteins associated with cytoskeletal function, resulting in an increase in the small intestine absorptive surface, thus assisting efficient permeation through the epithelial barrier.

Effects of two highly monounsaturated oils on lipid composition and enzyme activities in rat jejunum.

The effects of two monounsaturated fatty acid (MUFA) oils, olive oil (OO) and high-oleic sunflower oil (HOSO), with high content in oleic acid but differing in their non-fatty acid fraction, on brush-border membrane (BBM) lipid composition and fluidity and on mucosal enzyme activities of rat jejunum were studied. Animals were given semipurified diet with linoleic acid to prevent essential fatty acid deficiency (control group) or semipurified diet containing 10% of either OO or HOSO for 12 weeks. There was a significant decrease in the content of jejunal BBM phospholipids together with an increase in the level of free cholesterol in both oil-fed rats, when compared to control group. Although the increase in the BBM free cholesterol level was not statistically significant in HOSO-fed rats, a significant decrease in the phospholipid/free cholesterol ratio was found in both OO and HOSO-fed animals compared to control group. Rat jejunal BBM had a high level of free fatty acids which was increased in BBM isolated from OO and HOSO-fed animals. There was no statistical significant difference in the phospholipid distribution between the control and the OO group. However, HOSO-fed animals showed the lowest level of phosphatidylethanolamine together with the highest phosphatidylcholine content and the phosphatidylcholine/sphingomyelin ratio. The fatty acid pattern of jejunal BBM lipids was modified according to the major fatty acids in the oils. There was a decrease in both stearic acid (18:0) and linoleic acid (18:2 n-6), together with an increase in oleic acid (18:1 n-9) in jenunal BBM isolated from both oil experimental groups. All these results were accompanied by a significant increase in the BBM fluidity (as assessed by steady-state fluorescence polarization of diphenylhexatriene) isolated from oil-fed rat, when compared to control group. OO and HOSO-fed animals had the lowest activities of sucrase and maltase, while alkaline phosphatase activity only was decreased in HOSO-fed animals. The specific activity of maltase was not modified in any experimental rats. In summary, both MUFA oils induced similar effects on jejunal BBM lipid composition, fluidity, sucrase, maltase and lactase activities. Furthermore, HOSO intake resulted in a lowest alkaline phosphatase activity which was accompanied by changes in individual phospholipid composition. All these results suggest that effects of MUFA oils on jejunal BBM lipid composition and hydrolase activities are most likely due to the presence of high content of oleic acid rather than other components contained in the non-fatty acid of olive oil.

[Electron microscope observation on effect of kudingcha inspissation tea on small intestine villus in the adiposity rats].

OBJECTIVE: Experimental study on pharmacological action of Guang Dong kudingcha inspissation tea on small intestine villus in the adiposity rats (nutrition obesity). METHODS: By using electron microscope method, check on small intestine villus of 60 experiment rats of just wean and count and analyse and conclude. RESULTS: Under the scan electron imcroscope, the surface configuration on small intestine villus of model group and various kudingcha dosage groups is similar to the blank (P > 0.05), but fenfluramine group appear constriction on top end of small intestine villus. CONCLUSION: Compring with fenfluramine, Guang Dong kudingcha inspissation tea has not effect on configuration of small intestine of adiposity rats (nutrition obesity), but has more strong modulation function on fat tissue lipocyte hypertrophy and quantitative.

Effects of pectin on jejunal and ileal morphology and ultrastructure in adult mice.

The effects of pectin on jejunal and ileal morphology and ultrastructure were studied using adult male mice fed a semisynthetic diet containing 8% (w/w) cellulose or pectin for 30 days. No significant differences in the jejunal villus height between the 2 groups were found, but the jejunal crypt depth, and both the ileal villus height and crypt depth of the mice fed the pectin diet were significantly greater than those of the mice fed the cellulose diet. There were evident ultrastructural differences in the jejunal absorptive cells between 2 dietary groups: numerous intercellular spaces were observed in the jejunal absorptive cells of the mice fed the pectin diet, but not the cellulose diet. Moreover, the ileal absorptive cells of the mice fed the pectin diet contained numerous peroxisomes, whereas there were few in these cells of mice fed the cellulose diet. The functional characteristics of the ileum of the mice fed the pectin diet might be different from those fed the cellulose diet.

Ultrastructure of pre- and postcolostral enterocytes of the newborn calf.

Ten calves were used to elucidate the ultrastructure of enterocytes before and 24 h after colostral intake. Tissue samples were obtained from duodenum, jejunum (5 locations) and ileum. Protein A-gold technique was applied to immunoelectron-microscopically demonstrate colostral IgA. The prominent feature of the precolostral enterocytes are intracytoplasmic vacuoles. The frequency of vacuoles increases from cranial jejunum to ileum and from the villi bases to the tips. The appearance of absorptive vacuoles after colostral administration correlates with the incidence of precolostral empty vacuoles. Bovine IgA was detected in absorptive vacuoles and within the intestinal lumen of postcolostral calves. In addition to a diffuse IgA labelling of most vacuoles, a few corresponding enterocytic vacuoles labelled inhomogenously or negatively. This study demonstrates morphologically that the main site of colostral absorption is the middle-to-caudal region of the small intestine. Immunoelectron microscopy of IgA labelling provides indications of a selective IgA absorption in addition to pinocytosis.

[The effect of adrenoblockers on the ultrastructural changes in the epithelium and neural elements of the small intestine of suckling rabbits with experimental cholera]. / Vliianie adrenoblokatorov na ul'trastrukturnye izmeneniia épiteliia i nervnykh élementov tonkoi kishki krolikov-sosunkov pri éksperimental'noi kholere.

Infant rabbits (10-12-day old) were infected with El Tor 5879 culture via stomach. During the period of cholera vibrio adhesion (within 4 hr) and twice on the following day the animals were injected intraperitoneally with alpha- and beta-adrenoblockers pyrroxan and obsidan. It was established that mono- or combined therapy with adrenergic blocking agents prevents the vibrio adhesion, cholera vibrios were detected mainly in the small intestine lumen. In addition, adrenoblockers arrest adenylate cyclase activation realized through cAMP formation and subsequent diarrhea development.

Oral rehydration solutions: enhanced sodium absorption with gum arabic.

OBJECTIVE: To assess whether the addition of gum arabic (GA) to oral rehydration solutions (ORS) of either 60 or 90 mM sodium enhances net water and sodium absorption in rats. METHODS: Perfusion of a jejunal segment of male juvenile rats under anesthesia, and determination of net water and sodium absorption, and unidirectional fluid movements using appropriate markers. RESULTS: Addition of 5 and 10 g/L of GA increased the rates of sodium removal from the intestinal lumen perfused with ORS containing either 60 or 90 mM sodium. Net water absorption was unaffected, although GA tended to facilitate bidirectional fluid movement. The alteration of solute transport rates by the addition of 10 g/L GA was associated with an expansion of the basolateral intercellular spaces. CONCLUSIONS: A soluble fiber such as GA appears to be an effective enhancer of sodium absorption from ORS when tested in experimental animals. Since GA does not affect viscosity, an alteration of solute diffusibility through the brush border membrane and changes in intercellular compartments may underlie the observed improvement of sodium absorption.

Effects of docosahexaenoic acid and sardine oil diets on the ultrastructure of jejunal absorptive cells in adult mice.

The influence of docosahexaenoic acid (DHA) and sardine oil diets on the ultrastructure of jejunal absorptive cells was studied. Adult male Crj:CD-1 (ICR) mice were fed a fat-free semisynthetic diet supplemented with 5% (by weight) purified DHA ethyl ester, refined sardine oil, or palm oil. The mice received the DHA or palm oil diets for 7 days (groups 1 and 2) and the refined sardine oil or palm oil diets for 30 days (groups 3 and 4). There were significant ultrastructural changes in the jejunal absorptive cells between the mice fed on the palm oil diet and those receiving the DHA and sardine oil diets. The endoplasmic reticulum and Golgi apparatus of some jejunal absorptive cells in the mice fed on the palm oil diet for 7 and 30 days developed vacuolation on the upper site of the nucleus. In contrast, many granules, which appeared to be lipid droplets, were observed in the endoplasmic reticulum and Golgi apparatus of the jejunal absorptive cells in the DHA and sardine oil diet groups. These results suggest that ultrastructural differences in the jejunal absorptive cells between mice in the omega-3 fatty acid and palm oil diet groups may be associated with the changes in lipid metabolism.

Exposure of the rat small intestine to raw kidney beans results in reorganization of absorptive cell microvilli.

BACKGROUND/AIMS: A single exposure to raw kidney beans (RKB) results in vesiculation, shortening, and then regrowth of microvilli in the rat small intestine. This study investigated changes that occur in the structure of microvilli 2-10 hours after RKB exposure. METHODS: Circumferences of microvilli from absorptive cells obtained sequentially after challenge with RKB or chow were assigned to one of three groups: small, intermediate, or large. The distribution and concentration of actin in intact mucosae or isolated epithelial sheets were determined by confocal laser scanning microscopy, immunocytochemistry, and immunoblot analysis with specific probes. RESULTS: Six hours after exposure to RKB, most microvilli were large, abnormal in shape, and contained significantly more actin filaments than large microvilli from control rats. In addition, the fluorescence intensity of F-actin increased within injured microvilli without changes in the total intracellular actin concentration. By 8-10 hours after challenge with RKB, some microvilli remained larger than those of control rats but had resumed their normal shape and contained fewer actin filaments than at 6 hours. CONCLUSIONS: Exposure of the rat small intestine to RKB results in enlargement of absorptive cell microvilli and reorganization of membrane and core actin filaments without changes in intracellular actin concentration. Enlarged microvilli are rapidly repaired.

Uptake of maternal immunoglobulins in the enterocytes of suckling piglets: improved detection with a streptavidin-biotin bridge gold technique.

In ungulates, intestinal absorption of maternal immunoglobulins from colostrum plays a vital role in the acquisition of passive immunity during early neonatal life. In the present study we used post-embedding colloidal gold labeling to examine the intracellular localization of IgG in the jejunal enterocytes of miniature piglets suckled for 2 hr. Quantitation of the immunolabeling revealed that the most sensitive technique for IgG detection was the streptavidin bridge-gold technique. In this method, the LR White-embedded sections were labeled sequentially with biotinylated anti-porcine IgG, streptavidin, and biotinylated BSA conjugated to 10-nm colloidal gold. With this approach, we found the following sequence of maternal IgG accumulation: passage of IgG from colostrum through the brush border; binding to the apical plasma membrane; uptake in noncoated pits and invaginations; transport in endocytotic vesicles; and accumulation in granules in the apical cytoplasm.

Congenital sodium diarrhea with a partial defect in jejunal brush border membrane sodium transport, normal rectal transport, and resolving diarrhea.

Defective jejunal sodium/proton exchange causes severe, congenital secretory diarrhea. We report a boy who presented typically in utero, but in whom diarrhea resolved during the first year of life. Pregnancy was complicated by polyhydramnios, and an ultrasound at 31 weeks showed a distended fetal small intestine. The abdomen was grossly distended at birth, and profuse secretory diarrhea began immediately. He subsequently thrived on breast milk and electrolyte supplements. Studies of jejunal brush border sodium/proton exchange at 6 months showed a partial defect. Nonequilibrium rectal dialysis showed rectal sodium and potassium transport to be intact. Diarrhea lessened after 9 months, and the patient subsequently required occasional laxatives. These observations suggest that there is a spectrum of congenital abnormality in this exchanger, and that in children with incomplete defects normal colonic sodium salvage can subsequently mask net small intestinal secretion.