Distributional change of achromatic epithelial cells of the intestine in the fetuses and young of rats.

The achromatic epithelial cells (AEC), whose cellular materials remain unstained by several stains, e. g., H.E, PAS, Alcian blue, Orange G Anilin blue and Mucicarmin, are detected in the intestinal mucous epithelium of the Iar: Wistar Imamichi rat from the 19th day of gestation to the 21st day after birth. The results of light microscopic and transmission electron microscopic observations suggest that the rats AEC are equivalent to the previously reported vacuolar cells (VC) in cattle and in mice. The present paper describes that rat intestinal AEC appear first in the small intestine, and spread progressively toward the anal direction, while they disappear first in the cecum, and finally disappear at the ileum and the colon 22 days after birth.     

Annual mitotic activity in the intestinal epithelium of the musselCrenomytilus grayanus

The seasonal dynamics of cell reproduction in the intestinal epithelium of the musselCrenomytilus grayanus are described in detail. Mitotic indices in the intestinal epithelium varied throughout the year from 0.005 to 0.26% (averaged data) and from 0.003 to 0.37% (individual data). Cyclic seasonal changes were found in the mussel’s intestinal epithelium. In general, the average values of mitotic activity in the intestinal epithelium were low (the mitotic index was 0.13%); there was a rise in activity in late April–June and September and a decline in July–August and especially in January–March. The winter-early spring period was characterized by a profound inhibition of cell reproduction and the transition of cells to the resting state. An outburst of proliferation occurred in the spring, due to a manifold increase in the number of cells in the mitotic cycle. The musselC. grayanus may be a good model for the study of the two extreme states of proliferation and their alternation in marine animals in nature. The diel dynamics of mitotic activity in the intestinal epithelium were followed during the most active growth period (May). The mitotic index (MI) varied during the day within a narrow range, deviating from the daily average value by no more than one third; no pronounced diel rhythm was found. Optimum water temperatures for cell reproduction ranged from 5 to 18°C.     

Role of impaired regeneration of the mucosal epithelium in the pathogenesis of acute ulcers of the stomach and small intestine

The method of modelling of acute gastric and small intestinal ulcers by intraperitoneal administration of vincristine at a dose of 0.15-0.30 mg/kg body weight is suggested. The method is based on the property of vincristine to stop mitotic cell division at the stage of metaphase, thus impairing regeneration of the epithelium in the stomach and small intestine. The experiments on 20 dogs have shown that single vincristine administration caused the accumulation of cells with nuclei at the stage of metaphase in the generative areas. Mucosa defects formed at these sites acquired all the features of acute ulcers by the third day. The model demonstrates the pathogenetic role of impaired mucous epithelium regeneration and permits the studies of pathogenesis of acute ulcer formation.     

The potent induction of intestinal heme oxygenase by the organotin compound, bis(tri-n-butyltin)oxide

Oral administration of bis(tri-n-butyltin)oxide, an important organotin biocidal agent, produces a substantial elevation in heme oxygenase activity when measured at 16 hours in rat small intestine. An apparent Km for hemin of 100 microM is the same in both control and the organotin-induced 9,000 X g supernatant preparations. Concomitant with elevated heme oxygenase activity there occurs a substantial reduction in benzo(a)pyrene hydroxylase activity (approximately 20% of controls) and cytochrome P-450 concentration (approximately 60% of controls). These perturbations of heme metabolism in intestinal epithelium of the rat define an important new toxicological effect of organotins and raise the possibility that concurrent oral ingestion of environmental pollutants can directly affect the cytochrome P-450-dependent metabolism of other chemicals in the intestine.     

Rebuilding of rat intestinal mucous epithelium in prenatal ontogenesis

Morphological differentiation of the intestinal epithelium in the laboratory rat occurs between the 16th and 21st day of prenatal development. The pseudostratified epithelium is rebuilt into simple epithelium of the future lining. A characteristic sign of this rebuilding is formation of primitive folds, villi and intraepithelial vacuoles corresponding in submicroscopic picture with a secondary luminization. On the tips of folds and villi groups of cells released from the epithelium are observed. In these cells expression of activated caspase-3 confirms the presence of apoptosis in the process of cell death during epithelium rebuilding.     

Postnatal development of the vomeronasal epithelium in the rat: an ultrastructural study

Three basic types of cells are distinguished in the rat vomeronasal epithelium at birth: bipolar neurons, supporting cells, and basal cells. Neurons at this time include both immature and differentiated cells. By the end of the first postnatal week, all neurons show morphological signs of maturity in their cytoplasm, including abundant granular and smooth endoplasmic reticulum, neurotubules, dense lamellar bodies, apical centrioles, and tufts of microvilli. During the third week microvilli are more frequently encountered and appear to be longer and more branched. Supporting cells appear well-developed by the second day after birth. During the first ten days of life, supporting cells lose their centrioles and all of the complex associated with ciliary generation in the apical zone. Basal cells appear to be more numerous in newborns than in older animals. Protrusions projecting into the lumen are frequently observed in the epithelium of newborn animals, both on the dendrites of neurons and on supporting cells. After the third week, such protrusions are only observed in the transitional zone between the sensory and the non-sensory epithelia of the vomeronasal tubes. In this transitional zone, a fourth cell type showing apical protrusions with microvilli differentiates. Cytoplasm in this type resembles that of neighboring ciliated cells but has no cilia or centrioles. These transitional cells are considered to be cells in an intermediate state of differentiation, between that of the differentiated neurons and supporting cells of the sensory epithelium and that of the predominate ciliated cells of the non-sensory epithelium. The results suggest that by the end of the third week the vomeronasal epithelium is morphologically mature.     

Proteomic analysis of mouse jejunal epithelium and its response to infection with the intestinal nematode, Trichinella spiralis

Infection with the intestinal nematode Trichinella spiralis induces profound, but stereotypic pathological changes to the epithelium, which are common to many nematode infections. This study describes changes in jejunal epithelial protein expression that reflect these stereotypic responses. Adult male BALB/c mice were infected with T. spiralis, and groups (n = 4) examined on day 14/15 (time of worm rejection) were compared with uninfected controls (n = 4). Jejunal epithelium was harvested and extracted for two-dimensional gel electrophoresis. Tryptic peptide mass fingerprinting was used to create a reference map consisting of a total of 52 landmark spots. Of these, 16 were observed to change in intensity during infection. The changes observed at day 14/15 were of relevance to such mechanisms as lipid utilization and transport (increase in triacylglycerol lipase, and reduction in intestinal fatty acid binding protein) and innate immunity (appearance of intelectin-2). As a result, candidate molecules have been identified for further focused studies on their role in the host response to intestinal nematode infection.     

Growth and morphological changes in the small and the large intestine in piglets during the first three days after birth.

Growth and morphological changes in the small and the large intestine of piglets were examined during the first three days after birth. There was a 72% increase in small intestinal weight, virtually all of which occurred during the first day and was due primarily to a 115% increase in the weight of the mucosa. Associated with the tissue weight gain there was a 24% increase in small intestinal length, a 15% increase in small intestinal diameter, a 33-90% increase in villus height and a 14-51% increase in villus diameter, during the first day. The cellular population in the small intestinal mucosa, as indicated by its DNA content, increased progressively with age, and at three days had increased by 84-154%. The percentage increase in mucosal DNA content was highest in the duodenum, intermediate in the jejunum and lowest in the ileum. Histological features and tissue protein contents revealed a transient epithelial cellular swelling related to intracellular accumulation of protein on the first day. Protein accumulation was evident in the jejunum and ileum but not in the duodenum. The positions of the nuclei in the epithelial cells suggested that on the first day protein absorption was at a more advanced stage in the jejunum and the proximal ileum than in the distal ileum. Large intestinal weight increased by 33% during the first day and had doubled by the third day, and this weight gain was due to both mucosal and non-mucosal tissue growth. Villus-like structures were observed in the caecum and the proximal colon in piglets at birth and one day after birth but not in piglets three days after birth. It is speculated that such villus-like structures may have a functional significance during the transition to complete dependence on oral nutrition in newborns.     

Circadian variation of the cell proliferation in the jejunal epithelium of rats at weaning phase

Circadian variation in cell proliferation of the jejunal epithelium of 18-day-old rats was studied using the 2-h arrested metaphase score and crypt isolation method. A continuous decrease in the arrested metaphases occurred from 07.00 h to 13.00 h. From 17.00 h arrested metaphase values increased and were maintained at the higher level during the dark period as showed by Cosinor analyses (P < 0.05). These results indicate that in the young rat there is already a circadian variation in jejunal epithelial cell proliferation as early as 18 days. We can even suggest that the presence of a circadian rhythm at weaning contributes to the steady state of cell proliferation in the intestinal epithelium observed in adult life.     

Intracerebroventricular administration of leptin-induced apoptosis in the rat small intestinal mucosa

The localization of leptin and leptin receptors in the stomach and small intestine has been reported. Their function is still unknown, although leptin is a hormone that regulates appetite and fat-related metabolism. The small intestine is one of the important organs for regulating metabolism. The purpose of the present study was to investigate whether leptin regulates apoptosis in the small intestinal mucosa. Intestinal apoptosis was evaluated by percent fragmented DNA, electrophoresis, TUNEL staining, and western blotting analysis of caspase-3. Mucosal apoptosis in the rat jejunum and ileum was evaluated at 0, 3, 6, 12, and 24 hrs after injection. Rats were tested after ad libitum feeding and 24-hr fasting to exclude the anorectic effect of leptin. Leptin was injected intraperitoneally (ip) at a dose of 200 microg/rat and infused into the rat third cerebroventricle (icv) at a dose of 8 microg/rat. Leptin at a dose of 8 microg/rat significantly induced intestinal apoptosis in the small intestine at 3 and 6 hrs after icv administration in both ad libitum feeding and 24-hr fasted rats. This increase in apoptosis was not attenuated by vagotomy. Intestinal apoptosis increased 12 and 24 hrs after ip injection of leptin at a dose of 200 microg/rat. The peak of the increase in apoptosis in icv rats appeared earlier than that in ip rats. Leptin induced jejunal and ileal mucosal apoptosis in the rat, indicating that leptin might control intestinal function through the regulation of intestinal apoptosis.     

Nervonic acid is transferred from the maternal diet to milk and tissues of suckling rat pups

Three experiments were designed to investigate the metabolism of dietary nervonic acid (24:1n-9, NA) during reproduction in the rat. The first experiment determined the effect of early development on the sphingomyelin (SM) composition of rat heart and liver tissues. Rats were fed a standard chow diet and the SM fatty acid composition of the hearts and livers were analyzed of 18-20 day old fetuses, 14 day old sucklings and adult rats. The 18:0 content of SM decreases with age, while 23:0 and iso 24:0 increase with age. In the second experiment pregnant rats were fed diets supplemented with either canola, corn or peanut oil to determine the effect of diets high in 24:1n-9 and 24:0 on liver and heart SM at birth and after 14 days of suckling. Pups from the dams fed the corn oil diet had elevated 24:2n-6 in SM from heart and liver at birth, but the content of NA was not altered by dietary fat type. In the third experiment oil mixtures were designed to provide elevated levels of 22:1 and 24:1 (canola-N25), 22:0 and 24:0 (peanut-flax) or <0.01% of these fatty acids (olive-flax) and were supplemented to the diets of lactating rats. Canola-N25 oil supplemented to lactating rats resulted in increased 24:1n-9 and 24:1/24:0 with decreased 22:0 and 24:0 in milk SM relative to the other groups. The SM composition of livers of the suckling rats showed significant changes reflecting the changes in milk SM composition after 6 days of milk consumption. These experiments suggest that dietary NA and is not readily transferred across the placental barrier but does readily cross the mammary epithelium and is incorporated into milk SM. In addition, NA in milk appears to cross the intestinal epithelium where it is incorporated into the SM of heart and liver of suckling rats.     

Circadian Variation In Migration Velocity In Small Intestinal Epithelium

Abstract. The variation in migration rates of cells within the small intestinal epithelium was studied over a 24-hr period at 3-hr intervals (migration of cells was studied independently for the crypts and the villi using the changing distributions of [³H]TdR labelled cells as an indicator of cell migration).
Clear changes in the rates of cell movement were observed during a 24-hr period for both crypt and villus epithelium. the rates of cell migration in these two compartments did not correlate well with the exception of samples taken at 18.00 hours. At this time of day there appeared to be no cell movement at all in either crypts or villi. There was not a good correlation between the migration velocity throughout the day and the changes in the number of mitoses.
It is proposed that mitotic rates do not directly govern migration rates but that the converse may be true. Further, the lack of correlation between crypt and villus migration rates at any time of day suggest that the mechanisms controlling all movement in these two regions of small intestinal epithelium may be different.     

Circadian variation in migration velocity in small intestinal epithelium

The variation in migration rates of cells within the small intestinal epithelium was studied over a 24-hr period at 3-hr intervals (migration of cells was studied independently for the crypts and the villi using the changing distributions of [3H]TdR labelled cells as an indicator of cell migration). Clear changes in the rates of cell movement were observed during a 24-hr period for both crypt and villus epithelium. The rates of cell migration in these two compartments did not correlate well with the exception of samples taken at 18.00 hours. At this time of day there appeared to be no cell movement at all in either crypts or villi. There was not a good correlation between the migration velocity throughout the day and the changes in the number of mitoses. It is proposed that mitotic rates do not directly govern migration rates but that the converse may be true. Further, the lack of correlation between crypt and villus migration rates at any time of day suggest that the mechanisms controlling all movement in these two regions of small intestinal epithelium may be different.     

Analysis of intestinal cell proliferation after guanethidine-induced sympathectomy

Summary Guanethidine-induced sympathectomy in the rat during the neonatal period (injection of 20 g/g body weight every 48 h from day of birth until day 14) produces an absolute reduction in the number of sympathetic ganglion cells, but no significant alteration of body weight. Superior cervical ganglia show 79.8 % fewer cell bodies at 15 days and 92.3 % at 45 days; coeliac ganglia exhibit an 81.0 % reduction at 15 days and 89.6 % at 45 days in guanethidine-treated rats as compared to normal controls. The sympathetic ganglion cells that remain after treatment have an abnormal morphological appearance with distended mitochondria and depletion of endoplasmic reticulum. Sympathectomy produces a prolongation of the generation cycle time (Tc) as measured by the colchicine-induced mitotic arrest technique, and a decrease in labelling, mitotic, and migration indices. In addition, sympathectomy suppresses the amplitude of the circadian rhythm in mitotic activity. The general suppression of this activity in the intestinal epithelium is more pronounced in the jejunum and ileum than in the duodenum. Variation in the effectiveness of sympathectomy on the inhibition of intestinal cell proliferation may be related to segmental differences in cell proliferation, to segmental differences in innervation, and/or to segmental variation in the effectiveness of guanethidine.Supported by N.I.H. grant DE04557 to R.M.K. and N.I.H. grant 5-SO1-RR5373 to the University of Kansas Medical Center. The authors wish to acknowledge Charles A. Brownley, CIBA-Geigy, Summit New Jersey, U.S.A. for the gift of guanethidine-sulfate     

Induction of cell death in rat small intestine by ischemia reperfusion: differential roles of Fas/Fas ligand and Bcl-2/Bax systems depending upon cell types

Although ischemia reperfusion (I/R) induces apoptotic damage of mammalian small intestine, the molecular mechanism is largely unknown. We investigated the appearance of apoptosis at various time-points (0–24 h) of reperfusion after 1-h ischemia and the expression of various apoptosis-related proteins, such as Bcl-2, Bax, Fas, Fas ligand (FasL), activated caspase-3, and cytochrome c, immunohistochemically in rat small intestine. As assessed by TUNEL and electron microscopy, apoptotic cells were increased at 3 h of reperfusion in all intestinal parts (villous epithelium, crypt epithelium, and stroma of intestine). Moreover, the TUNEL-positive cells in the stroma were later identified as T cells. The expression of Fas and FasL as well as activated caspase-3 was markedly increased at 3 h of reperfusion in the stroma. In the villous epithelium, a transient decrease in Bcl-2 expression was found while in the crypt epithelium, Fas expression was induced. Finally, intraperitoneal injection of leupeptin (an SH-protease inhibitor) after I/R resulted in a significant inhibition of the induction of apoptosis in the stroma and crypt epithelium. Our results indicate that the triggering molecules of apoptosis in the I/R rat small intestine may vary depending on cell type and that the use of a broad-spectrum protease inhibitor may reduce intestinal damage.     

A study of diurnal proliferative activity in tumour and small intestine of C3H mice bearing a transplanted mammary carcinoma

Diurnal changes in proliferative activity were investigated in tumour and small intestinal epithelium of mice bearing a transplanted mammary carcinoma. In addition to mitotic and labelling index studies, the metaphase-arrest technique with vincristine (VCR) was employed. In the tumour there was no clear evidence of a significant diurnal rhythm in proliferative activity but in the small intestinal epithelium such a rhythm was clearly demonstrated. A higher cell production rate (kB) measured by metaphase-arrest and higher labelling and mitotic indices were seen in the mid to late part of the dark period. The peak mitotic index was seen 3 to 6 h after the labelling peak in the small intestine. The basal third of the crypt which is believed to include the stem cell compartment of this tissue showed larger diurnal fluctuations in both labelling index and kB than the rest of the proliferative compartment.     

An intestinal galactose-specific lectin mediates the binding of murine IgE to mouse intestinal epithelial cells.

A number of lactose-binding lectins have recently been identified in the rat and mouse intestine, one of which corresponds to the C-terminal domain of IgE-binding proteins, originally identified in rat basophilic leukemia (RBL) cells and mouse 3T3 fibroblasts. In the present report, we describe the affinity purification of a rat intestinal lactose-specific lectin which binds murine IgE antibodies. This binding most likely occurs via the immunoglobulin carbohydrate chains, as it is inhibited by lactose. This intestinal lectin molecule is also immunologically related to the previously described IgE-binding protein (epsilon BP) isolated from RBL cells, since it is recognized by antibodies raised against recombinant epsilon BP. This intestinal form of epsilon BP has a molecular mass of 17.5 kDa, which is much lower than that of its RBL cell analogue (31 kDa). The attachment of IgE to the mouse intestinal epithelium was demonstrated by immunohistochemistry, along with the presence of a corresponding mouse intestinal epsilon BP. The carbohydrate-dependent nature of this attachment was established by demonstrating that IgE binding to mouse epithelium was specifically abolished by lactose (4 mM) and by a blood-group-A-active tetrasaccharide (0.2 mM), but not by mannose (10 mM). Finally, the association of IgE with the mouse intestinal epithelium was prevented by competition with the purified IgE-binding lectin isolated from rat intestine. Although the physiological function of this intestinal protein is still unknown, the finding that IgE binds to a lectin in the intestinal epithelium pinpoints a possible novel mechanism for the regulation of IgE-mediated disorders, such as food allergy.     

Oral dosing of neonatal mice with sucrose reduces infection with Cryptosporidium parvum

Cryptosporidium parvum is a significant cause of diarrheal disease in humans and economically important livestock species. There is no effective treatment available for this protozoan parasite. Mechanisms of intestinal colonization by C. parvum are not well understood, but it has been suggested that the parasite may utilize a lectin-like receptor. We used an infant mouse model to test whether high sugar concentrations in the intestine would affect in vivo colonization with C. parvum. We found that a single oral dose of sucrose, administered to mice at the time of, or 24 hr before, challenge with C. parvum significantly reduced infection. Significant reduction of infection was also seen in mice given isomaltose. Histologic examination of intestinal sections of mice treated with sucrose or isomaltose, but not other sugars, showed marked vacuolation of the small intestinal epithelium 1 day after treatment. Three days after treatment, tissue appeared normal. Thus, sucrose and, to a lesser extent, isomaltose reduced in vivo colonization with C. parvum and altered epithelial cell morphology in intestines of mice.     

Determination of parameters of the survival curve of the stem cells of the intestinal crypts by LD50 and the regenerated crypt count. Determination of the RBE of p(65) + Be neutrons

The early effects of an irradiation on the intestinal epithelium have been evaluated, at the tissular level, by LD50 after single and multifraction irradiation, and, at the cellular level, by numeration of the regenerated intestinal crypts (Withers technique) after a single fraction irradiation. From the set of informations provided by both criteria, one derived the values of the parameters defining the survival curve of the intestinal clonogenic crypt cells after irradiation by gamma-rays (two component model): D0 = 1.5 Gy, 1D0 = 4.5 Gy, nD0 = 2.25 Gy and n = 20. In other respects, the p(65) + Be neutrons RBE (ref. 60-Cobalt) after a single fraction irradiation is equal to 1.75 +/- 0.2 and 1.64 +/- 0.25 for the LD50 at the 5th day and for the regeneration of 50 crypts after 3.5 days respectively.     

DARPP-32 in the ciliary epithelium of the eye: a neurotransmitter-regulated phosphoprotein of brain localizes to secretory cells

DARPP-32, a phosphoprotein enriched in dopaminoceptive brain neurons containing the D-1 receptor subtype, probably functions as an intracellular third messenger to mediate some of the physiological effects of dopamine at the D-1 receptor. By immunohistochemistry in rat, cat, Rhesus monkey, and human, we have localized DARPP-32 to the non-pigmented epithelium of the ciliary body, the innermost layer of the bi-layered epithelium responsible for secretion of aqueous humor into the eye. The immunoreactive protein in rat ciliary body, identified by immunolabeling of a ciliary body extract separated by sodium dodecyl sulfate/polyacrylamide gel electrophoresis, is indistinguishable from DARPP-32 derived from rat caudatoputamen. By analogy with brain, we propose that DARPP-32 may act as a third messenger in the ciliary epithelium, probably through a dopaminergic mechanism.