Protein restriction during puberty alters nutritional parameters and affects ovarian and uterine histomorphometry in adulthood in rats.

In a large part of the population inefficient ingestion of proteins, whether for cultural, aesthetic or economic reasons, is a global concern. Low-protein diets can cause severe functional complications, mainly during the development and maturation of organs and systems, including the female reproductive system. The present study investigated the effect of nutritional protein restriction during puberty on the oestrous cycle and expression of sex steroid receptors (AR, ERα e ERß) in ovarian and uterine tissues of adult rats. Protein restriction promoted lower body weight gain, feed efficiency and higher caloric intake. There was an increase in the oestrus phase arrest without changing the total length of the oestrous cycle. The consumption of low-protein diet also reduced the thickness of the uterine endometrium (uterine epithelium and endometrial stroma) in addition to increasing the number of primary and atretic follicles in the ovaries. Furthermore, the low-protein diet reduced the levels of androgen receptor (AR) and increased the oestrogen receptor ß (ERß) in the ovary, while no significant changes were observed in the uterus. Our study reinforces the importance of adequate protein intake during puberty, since physiological changes in this developmental period interfere with the histomorphometry of the ovaries and uteri, possibly resulting in impaired folliculogenesis and fertility in the reproductive period.

Stereology shows that damaged liver recovers after protein refeeding.

OBJECTIVE: The aim of the present study was to investigate the putative effects of a low-protein diet on the three-dimensional structure of hepatocytes and determine whether this scenario could be reversed by restoring the adequate levels of protein to the diet. METHODS: Using design-based stereology, the total number and volume of hepatocytes were estimated in the liver of mice in healthy and altered (by protein malnutrition) conditions and after protein renutrition. RESULTS: This study demonstrated a 65% decrease in the liver volume (3302 mm3 for the control for undernourished versus 1141 mm3 for the undernourished group) accompanied by a 46% reduction in the hepatocyte volume (8223 µm3 for the control for undernourished versus 4475 µm3 for the undernourished group) and a 90% increase in the total number of binucleate hepatocytes (1 549 393 for the control for undernourished versus 2 941 353 for the undernourished group). Reinstating a normoproteinic diet (12% casein) proved to be effective in restoring the size of hepatocytes, leading to an 85% increase in the total number of uninucleate hepatocytes (15 988 560 for the undernourished versus 29 600 520 for the renourished group), and partially reversed the liver atrophy. CONCLUSIONS: Awareness of these data will add to a better morphologic understanding of malnutrition-induced hepatopathies and will help clinicians improve the diagnosis and treatment of this condition in humans and in veterinary practice.

Long-term effect of a chronic low-protein multideficient diet on the heart: Hypertension and heart failure in chronically malnourished young adult rats.

BACKGROUND: We investigated whether a chronic low-protein multideficient diet (BRD) from weaning turns on cardiovascular adaptive responses that could culminate in hypertension and heart failure. METHODS AND RESULTS: Systolic pressure (SP) and heart rate (HR) were determined in CTRL (normal diet) and BRD rats. Plasma albumin, plasma urea and urinary urea excretion decreased in BRD rats. In this group, echocardiography and the Langendorff technique showed: (i) increased HR and hypertension; (ii) decreased LVDP, dP/dtmax, dP/dtmin, cardiac output, ejection fraction, stroke volume and left ventricular diameter. BRD rats were less sensitive to isoproterenol (ISO) in LVDP and dP/dtmax, with unchanged dP/dtmin; Pressure-volume relationships indicated left-oriented shifts in LVDP, SP and DP, and decreased capacitance compared to CTRL. BRD rats had higher cardiac and lung indexes, accompanied by muscle atrophy and recent ventricular-infarcted areas, higher ventricular ß1-AR content, and decreased ß2-AR and α1-AR. Propranolol treatment gave similar ISO responses in both groups, disappearance of the infarcted regions and, except for ß2-AR, recovery of normal receptor expression. BRD rats had intense stimulation of plasma membrane Ca2+-ATPase (PMCA) activity, with increased Ca2+ affinity and inhibition of the sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA). Ventricular phospholamban increased and Na+/Ca2+ exchanger decreased. PMCA activity correlated with an increase in its PKC-mediated phosphorylation, overlying a decrease in PKA-catalyzed phosphorylation. Propranolol normalized PKC and PKA activities with recovery of PMCA but not SERCA. CONCLUSION: BRD triggers sympathetic exacerbation and dysfunction in Ca2+ handling, accompanied by early onset of hypertension and left ventricle congestive heart failure.

Protein Malnutrition During Juvenile Age Increases Ileal and Colonic Permeability in Rats.

Protein malnutrition can lead to morphological and functional changes in jejunum and ileum, affecting permeability to luminal contents. Regarding the large intestine, data are scarce, especially at juvenile age. We investigated whether low-protein (LP) diet could modify ileal and colonic permeability and epithelial morphology in young rats. Isocaloric diets containing 26% (control diet) or 4% protein were given to male rats between postnatal days 40 and 60. LP-diet animals failed to gain weight and displayed decreased plasma zinc levels (a marker of micronutrient deficiency). In addition, transepithelial electrical resistance and occludin expression were reduced in their ileum and colon, indicating increased gut permeability. Macromolecule transit was not modified. Finally, LP diet induced shortening of colonic crypts without affecting muscle thickness. These data show that protein malnutrition increases not only ileum but also colon permeability in juvenile rats. Enhanced exposure to colonic luminal entities may be an additional component in the pathophysiology of protein malnutrition.

The influence of protein malnutrition on biological and immunomodulatory aspects of bone marrow mesenchymal stem cells.

Tissues that require a great supply of nutrients and possess high metabolic demands, such as lympho-hemopoietics tissues, are the first to be affected by protein malnutrition (PM). Thus, PM directly affects hemopoiesis and the production and function of immune cells. Consequently, malnourished individuals are more susceptible to infections. Mesenchymal stem cells (MSCs) have immunomodulatory properties and are important in the formation of lympho-hemopoietic stroma. Since an adequate supply of nutrients is essential to sustain stroma formation, which is mainly constituted of MSCs and differentiated cells originated from them, this study investigated whether PM would influence some biological and immunomodulatory aspects of MSCs. Two-month-old Balb/c mice were divided into control and malnourished groups receiving normoproteic or hypoproteic diets, respectively (12% and 2% of protein) for 28 days. MSCs obtained from control (MSCct) and malnourished (MSCmaln) animals were characterized. In addition, the proliferation rate and cell cycle protein expression were determined, but no differences in these parameters were observed. In order to evaluate whether PM affects the immunomodulatory properties of MSCs, the expression of NFκB and STAT-3, and the production of IL-1α, IL-1ß, IL-6, IL-10, TGF-ß and TNF-α by MSCs were assessed. MSCmaln expressed lower levels of NF-κB and the production of IL-1ß, IL-6 and TGF-ß was significantly influenced by PM. Furthermore, MSCct and MSCmaln culture supernatants affected lymphocyte and macrophage proliferation. However, MSCmaln did not reduce the production of IFN-γ nor stimulate the production of IL-10 in lymphocytes in the same manner as observed in MSCct. Overall, this study implied that PM modifies immunosuppressive properties of MSCs.

Effects of environmental enrichment on blood vessels in the optic tract of malnourished rats: A morphological and morphometric analysis.

OBJECTIVES: This study aimed to compare the effects of environmental enrichment in nourished (on a diet containing 16% protein) and malnourished (on a diet containing 6% protein) rats during the critical period of brain development, specifically focusing on the optic nerve. METHODS: By means of morphologic and morphometric assessment of the optic nerve, we analyzed the changes caused by diet and stimulation (environmental enrichment) on postnatal day 35, a time point ideal for such morphological analysis since developmental processes are considered complete at this age. RESULTS: Malnourished animals presented low body and brain weights and high body-to-brain weight ratio compared to well-nourished rats. Furthermore, malnourished animals showed morphological changes in the optic nerve such as edema and vacuolization characterized by increased interstitial space. The malnourished-stimulated group presented lesions characteristic of early protein malnutrition but were milder than lesions exhibited by malnourished-non-stimulated group. The morphometric analysis revealed no difference in glial cell density between groups, but there was significantly higher blood vessel density in the stimulated rats, independent of their nutritional condition. DISCUSSION: Our data indicate that protein malnutrition imposed during the critical period of brain development alters the cytoarchitecture of the optic nerve. In addition, we affirm that a 1-hour exposure to an enriched environment everyday was sufficient for tissue preservation in rats maintained on a low-protein diet. This protective effect might be related to angiogenesis, as confirmed by the increased vascular density observed in morphometric analyses.

Taurine supplementation preserves hypothalamic leptin action in normal and protein-restricted mice fed on a high-fat diet.

Malnutrition programs the neuroendocrine axis by disruption of food-intake control, leading to obesity. Taurine (Tau) is neuroprotective and improves anorexigenic actions in the hypothalamus. We evaluated the hypothalamic gene-expression profile and food-intake control in protein-restricted mice submitted to a high-fat diet (HFD) and Tau supplementation. Mice were fed on a control (14 % protein-C) or a protein-restricted diet (6 % protein-R) for 6 weeks. Thereafter, mice received, or not, HFD for 8 weeks (CH and RH) with or without 5 % Tau supplementation (CHT and RHT). Protein restriction led to higher food intake, but calories were matched to controls. Excessive calorie intake occurred in HFD mice and this was prevented by Tau supplementation only in the CH group. Additionally, RH and CH mice developed hypothalamic leptin resistance, which was prevented by Tau. Global alterations in the expressions of genes involved in hypothalamic metabolism, cellular defense, apoptosis and endoplasmic reticulum stress pathways were induced by dietary manipulations and Tau treatment. The orexigenic peptides NPY and AgRP were increased by protein restriction and lowered by the HFD. The anorexigenic peptide Pomc was increased by HFD, and this was prevented by Tau only in CH mice. Thus, food intake was disrupted by dietary protein restriction and obesity. HFD-induced alterations were not enhanced by previous protein deficiency, but the some beneficial effects of Tau supplementation upon food intake were blunted by protein restriction. Tau effects upon feeding behavior control are complex and involve interactions with a vast gene network, preventing hypothalamic leptin resistance.

Liver damage and caspase-dependent apoptosis is related to protein malnutrition in mice: effect of methionine.

This study aimed to determine whether the effects on the mouse liver caused by three periods of feeding a protein-free diet for 5 days followed by a normal complete diet for 5 days (3PFD-CD) are prevented by a constant methionine supply (3PFD+Met-CD). The expressions of carbonic anhydrase III (CAIII), fatty acid synthase (FAS), glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and glutathione S-transferase P1 (GSTP1) were assessed by proteomics and reverse transcriptase-polymerase chain reactions. The liver redox status was examined by measuring the activities of superoxide dismutase (SOD) and catalase (CAT), as well as protein carbonylation. Because oxidative stress can result in apoptosis, the activity and content of caspase-3, as well as the x-linked inhibitor of the apoptosis protein (XIAP) and mitochondrial caspase-independent apoptosis inducing factor (AIF) contents were assessed. In addition, the liver histomorphology was examined. Compared to the controls fed a normal complete diet throughout, feeding with 3PFD-CD increased the FAS content, decreased the CAIII content, decreased both the SOD and CAT activities, and increased protein carbonylation. It also activated caspase-3, decreased the XIAP content, decreased the AIF content, increased the number of GSTP1-positive foci and caspase-3-positive cells, and caused fatty livers. Conversely, the changes were lessened to varying degrees in mice fed 3PFD+Met-CD. The present results indicate that a regular Met supply lessens the biochemical changes, damage, and caspase-dependent apoptosis provoked by recurrent dietary amino acid deprivation in the mouse liver.

Estudo do perfil de expressão de componentes da via de sinalização sonic hedgehog em displasia epitelial oral / Study of the expression profile of components of sonic hedgehog signaling pathway in oral epithelial dysplasia

A displasia epitelial oral (DEO) é um aspecto histológico descrito em lesões potencialmente malignas, cujos mecanismos relacionados a patogênese e potencial de transformação são pouco conhecidos. Sabendo-se que a via de sinalização Sonic Hedgehog(SHH)tem participação no desenvolvimento do carcinoma escamocelular de boca(CEB) e que as proteínas relacionadas a esta via de sinalização estão envolvidas nos mecanismos biológicos relacionados a iniciação e progressão de tumores humanos. O objetivo deste trabalho foi estudar a expressão das proteínas da via de sinalização SHH em DEO, a fim de contribuir para o conhecimento do perfil biológico desta lesão...

Oral epithelial dysplasia (OED) is a histological aspect described in premalignant lesions and themechanisms related to the pathogenesis and malignant progression are poorly understood. It is knownthat Sonic Hedgehog (SHH) signaling pathway participates in the development of oral squamous cellcarcinoma, and proteins related to this cascade are involved in biological mechanisms related to theinitiation and progression of human tumors. The aim of this study was to investigate SHH signalingmolecules in OED, in order to contribute to the knowledge of the biological profile of this lesion...

Differential effects of undernourishment on the differentiation and maturation of rat enteric neurons.

The colocalization, number, and size of various classes of enteric neurons immunoreactive (IR) for the purinergic P2X2 and P2X7 receptors (P2X2R, P2X7R) were analyzed in the myenteric and submucosal plexuses of control, undernourished, and re-fed rats. Pregnant rats were exposed to undernourishment (protein-deprivation) or fed a control diet, and their offspring comprised the following experimental groups: rats exposed to a normal diet throughout gestation until postnatal day (P)42, rats protein-deprived throughout gestation and until P42, and rats protein-deprived throughout gestation until P21 and then given a normal diet until P42. Immunohistochemistry was performed on the myenteric and submucosal plexuses to evaluate immunoreactivity for P2X2R, P2X7R, nitric oxide synthase (NOS), choline acetyltransferase (ChAT), calbindin, and calretinin. Double-immunohistochemistry of the myenteric and submucosal plexuses demonstrated that 100% of NOS-IR, calbindin-IR, calretinin-IR, and ChAT-IR neurons in all groups also expressed P2X2R and P2X7R. Neuronal density increased in the myenteric and submucosal plexuses of undernourished rats compared with controls. The average size (profile area) of some types of neurons in the myenteric and submucosal plexuses was smaller in the undernourished than in the control animals. These changes appeared to be reversible, as animals initially undernourished but then fed a normal diet at P21 (re-feeding) were similar to controls. Thus, P2X2R and P2X7R are present in NOS-positive inhibitory neurons, calbindin- and calretinin-positive intrinsic primary afferent neurons, cholinergic secretomotor neurons, and vasomotor neurons in rats. Alterations in these neurons during undernourishment are reversible following re-feeding.

Transgenerational endocrine pancreatic adaptation in mice from maternal protein restriction in utero.

Exposure of pregnant mice to a low-protein diet (LP) impairs endocrine pancreas development in their offspring. There is evidence that this phenomenon may persist in subsequent generations. Here, we evaluated the effect of LP on glucose metabolism and pancreatic morphometry in the F3 offspring of mice at birth and weaning. LP pups in the first generation were smaller at birth, but catch-up growth; F2-LP offspring had higher body mass at birth, but there was no difference in the F3 generation. The pancreatic mass decreased in F1-LP through F3-LP at birth but increased in F2-LP at weaning. The islet volume density and diameter were smaller in all restricted groups at day 1 and 21, and F1-LP had the lowest islet number; at birth, beta cell mass was smaller in F1-LP through F3-LP and remained low throughout suckling. At day 1 and 21, pups were normoglycemic, but were hypoinsulinemic at weaning. Thus, protein restriction in mice during pregnancy produces morphologic changes in pancreatic islets, suggesting that glucose homeostasis is maintained by an increased sensitivity to insulin during the early stages of life in offspring over three consecutive generations.

Glycogen stores are impaired in hypothalamic nuclei of rats malnourished during early life.

Perinatal nutrition has persistent influences on neural development and cognition. In humans and other animals, protein malnutrition during the perinatal period causes permanent changes, inducing to adulthood metabolic syndrome. Feeding is mainly modulated by neural and hormonal inputs to the hypothalamus. Hypothalamic glycogen stores are a source of glucose in high energetic demands, as during development of neural circuits. As some hypothalamic circuits are formed during lactation, we studied the effects of malnutrition, during the first 10 days of lactation, on glycogen stores in hypothalamic nuclei involved in the control of energy metabolism. Female pregnant rats were fed ad libitum with a normal protein diet (22% protein). After delivery, each dam was kept with 6 male pups. During the first 10 days of lactation, dams from the experimental group received a protein-free diet and the control group a normoprotein diet. By post-natal day 10 (P10), glycogen stores were very high in the arcuate nucleus and median eminence of control group. Glycogen stores decreased during development. In P20 control animals, glycogen stores were lower when compared to P10 control animals. Animals submitted to malnutrition presented a staining even lower than control ones. After P45, it was difficult to determine differences between control and diet groups because glycogen stores were reduced. We also showed that tanycytes were the cells presenting glycogen stores. Our data reinforce the concept that maternal nutritional state during lactation may be critical for neurodevelopment since it resulted in a low hypothalamic glycogen store, which may be critical for establishment of neuronal circuitry.

Atrophy and neuron loss: effects of a protein-deficient diet on sympathetic neurons.

Protein deficiency is one of the biggest public health problems in the world, accounting for about 30-40% of hospital admissions in developing countries. Nutritional deficiencies lead to alterations in the peripheral nervous system and in the digestive system. Most studies have focused on the effects of protein-deficient diets on the enteric neurons, but not on sympathetic ganglia, which supply extrinsic sympathetic input to the digestive system. Hence, in this study, we investigated whether a protein-restricted diet would affect the quantitative structure of rat coeliac ganglion neurons. Five male Wistar rats (undernourished group) were given a pre- and postnatal hypoproteinic diet receiving 5% casein, whereas the nourished group (n = 5) was fed with 20% casein (normoproteinic diet). Blood tests were carried out on the animals, e.g., glucose, leptin, and triglyceride plasma concentrations. The main structural findings in this study were that a protein-deficient diet (5% casein) caused coeliac ganglion (78%) and coeliac ganglion neurons (24%) to atrophy and led to neuron loss (63%). Therefore, the fall in the total number of coeliac ganglion neurons in protein-restricted rats contrasts strongly with no neuron losses previously described for the enteric neurons of animals subjected to similar protein-restriction diets. Discrepancies between our figures and the data for enteric neurons (using very similar protein-restriction protocols) may be attributable to the counting method used. In light of this, further systematic investigations comparing 2-D and 3-D quantitative methods are warranted to provide even more advanced data on the effects that a protein-deficient diet may exert on sympathetic neurons. (c) 2009 Wiley-Liss, Inc.

Dexamethasone treatment in vivo counteracts the functional pancreatic islet alterations caused by malnourishment in rats.

The effects of dexamethasone (Dex) on the metabolic parameters, peripheral insulin, and glucose sensitivity in vivo as well as on islet function ex vivo of rats submitted to low-protein diet were analyzed. Dexamethasone (1.0 mg/kg body weight) was administered intraperitoneally daily to adult Wistar rats fed on a normal-protein diet or low-protein diet (LPD) for 5 days, whereas control rats fed on a normal-protein diet or low-protein diet (LP) received saline alone. At the end of the experimental period, LP rats showed a significant reduction in serum insulin, total serum protein, and serum albumin levels compared with rats fed on a normal-protein diet (P<.05). All these parameters tended to be normalized in LPD rats (P<.05); furthermore, these rats exhibited increased serum glucose and nonesterified fatty acid levels compared with LP rats (P<.05). Rats submitted to the low-protein diet demonstrated normal peripheral glucose sensitivity and improved peripheral insulin sensitivity, which was reversed by Dex treatment. A reduced area of islets from LP rats was partially recovered in LPD rats (P<.05). At 16.7 mmol/L glucose, insulin secretion from LPD islets was also partially recovered and was significantly higher than that from LP islets (P<.05). In conclusion, induction of insulin resistance by Dex treatment reverses most of the metabolic alterations in rats submitted to a low-protein diet. In addition, several islet functions were also improved by Dex, confirming the plasticity of pancreatic islets in adverse conditions.

Intestinal ascending colon morphometrics in rats submitted to severe protein malnutrition / Morfometría de la pared intestinal del colon ascendente de ratas sometidas a desnutrición proteica severa

This paper aims to verify the effects of severe protein malnutrition over the intestinal ascending colon morphometrics in adult rats. 12 rats (90 days old) were divided into 2 groups: control (n = 5) and malnutritioned (n = 7). In the following 90 days, the rats of the control group received a 24 percent protein chow as the malnourished group received 4 percent protein chow. The animals were submitted to euthanasia according to the anesthetic protocol. Colon segments were collected and submitted to routine histological processing. The cuts were stained with HE and histochemical techniques for mucines. The morphometric analyses showed the sustenance of the whole wall and muscle tunic thickness, as well as the reduction of the thickness of the mucosa tunic, the amount of goblet cells, the depth of the crypt and the height of the enterocytes as well as their nucleus on malnutritioned animals. The data suggest that protein malnutrition causes alterations on adult rat ascending colon intestinal morphometrics, especially in tissues which present a high level of cell turnover such as the mucosa tunic and consequently their structures such as the enterocytes, goblet cells, and crypts

El objetivo de este trabajo fue verificar los efectos de la desnutrición proteica severa sobre la morfometría de la pared intestinal del colon ascendente de ratas adultas. Fueron utilizadas 12 ratas (90 días de edad), divididas en dos grupos: control (n=5) y desnutrido (n=7). En los 90 días siguientes, las ratas del grupo control recibieron ración con 24 por ciento de contenido proteico y los del grupo desnutrido con 4 por ciento. Los animales fueron eutanasiados de acuerdo al protocolo anestésico. Segmentos del colon fueron retirados y sometidos a procesamiento histológico de rutina. Los cortes fueron teñidos con HE y técnicas histoquímicas para mucinas. El análisis morfométrico mostró la mantención de la pared total y del grosor de la túnica muscular, y reducción en el espesor de la túnica mucosa, en el número de células caliciformes, en la profundidad de las criptas y en la altura de los enterocitos y de sus núcleos, en los animales desnutridos. Los datos obtenidos sugieren que la desnutrición proteica provoca alteraciones en la morfometría intestinal del colon ascendente de ratas adultas, principalmente en tejidos de alto índice de renovación celular como la mucosa y, consecuentemente, de sus estructuras como los enterocitos, células caliciformes y criptas

Adult cardiorenal benefits from postnatal fish oil supplement in rat offspring of low-protein pregnancies.

We investigated the effect of fish oil (FO) treatment on cardiorenal structure of adult offspring from low-protein pregnancies. Three month old offspring were assigned to eight groups (four male groups and four female groups, n=8 each) (NP=normal-protein diet, LP=low-protein diet): NP, LP, NP plus FO, and LP plus FO. Left ventricle and kidney were analyzed with light microscopy and stereology. The both sexes of LP offspring showed 30% lower birth weights than the respective NP offspring and high blood pressure (BP) levels in adulthood which was efficiently reduced by FO treatment. In the heart, FO treated the cardiomyocyte hypertrophy, the vascularization impairment, and decreased the cardiomyocyte loss usually observed in adult LP offspring. In the kidney, FO treated, in the male, the imbalance of the cortex-to-medulla ratio observed in both sexes of LP offspring, and reduced the glomeruli loss in the LP offspring. The positive correlation between the number of cardiomyocyte nuclei later in life and the body mass (BM) at birth was significant only in both sexes of LP offspring and this correlation disappeared in LP plus fish oil offspring. The positive correlation between the number of glomeruli later in life and the BM at birth was significant in NP male offspring and in both sexes of LP offspring. In conclusion, FO supplement, which is a rich source of n-3 fatty acids (DHA and EPA), has beneficial effects on BP control and cardiac and renal adverse remodeling usually seen in offspring of the LP pregnancies.

Is gastric ulceration different in normal and malnourished rats?

Protein malnutrition can adversely affect all tissues. The aim of the present study was to test the hypothesis that protein deprivation influences gastric ulcer formation, as well as metabolism and organ growth, in rats. In the present study, there was a significant reduction in the body and organ weight of rats fed a low-protein diet (P<0.001). Malnourished rats were less susceptible to ulceration of the gastric mucosa in ethanol and indomethacin models of acute gastric ulcers when compared with rats fed a normoproteic diet (17 % protein). Mucus production and prostaglandin E2 formation increased in malnourished rats, possibly explaining the lower number of acute ulcers in these animals. Pylorus ligature altered gastric juice composition (increased pH and gastric volume, and decreased total acid concentration) in the animal group fed a low-protein diet compared with the group fed a diet containing 17 % protein (P<0.05). The gastric mucosa was more damaged in malnourished rats than in normal rats evaluated for 14 d after acetic acid injection (P<0.001). Malnourished rats exhibited resistance to acute gastric lesions, owing to an increase in prostaglandin GE2 release and mucus secretion, which protected their gastric mucosa. This phenomenon was not seen in subchronic gastric ulceration.

The mossy fiber system of the hippocampal formation is decreased by chronic and postnatal but not by prenatal protein malnutrition in rats.

We tested in 70-day-old Sprague-Dawley rats, whether malnutrition imposed during different periods of hippocampal development produced deleterious effects on the total reference volume of the mossy fiber system. Animals were treated under four nutritional conditions: (a) well nourished; (b) prenatal protein malnourished; (c) chronic protein malnourished and (d) postnatal protein malnourished. Timm's stained material was used in coronal hippocampal sections (40 microm) to estimate--using the Principle of Cavalieri--the total reference volume of the mossy fiber system in each experimental group. Our results show that chronic and postnatal protein malnourished, but not prenatal malnourished rats, decrease the mossy fiber system and the total reference volume of the mossy fiber system are selectively vulnerable to the type of dietary restriction. Thus, chronic and posnatal protein malnutrition produce deleterious effects, but only rats under prenatal protein malnutrition were able to reorganize synapses in this plexus. These findings raise the possibility that chronic malnutrition, as a long-term stressful factor, might be an important paradigm to test structural hippocampal changes that produce physiological and pathophysiological effects, or the possibility to recover its function for nutritional rehabilitation.

Effect of protein and vitamin B deficiency on the morpho-quantitative aspects of the myenteric plexus of the descending colon of adult rats.

We carried out this work with the purpose of studying the effects of protein and vitamin B deficiency on the morphologic and quantitative aspects of the myenteric plexus of the descending colon of adult Rattus norvegicus. Twenty-eight rats were divided in two groups, one of them receiving chow with 22% protein level (control) and the other fed with chow having 8% protein level without vitamin B supplementation, during 120 days. Whole-mounts of the descending colon were prepared and stained with Giemsa, NADH-diaphorase and NADPH-diaphorase. The undernourished rats had a body weight 11.84% less than the control group. Relative to the controls, the experimental group had a colonic area 48% smaller, 51.9% less Giemsa-stained neurons, 28.3% less NADH-diaphorase positive neurons and 24.2% less NADPH-diaphorase positive neurons.

Compartmentalisation between gut and lung mucosae in a model of secondary immunodeficiency: effect of thymomodulin.

UNLABELLED: Compartmentalisation of mucosal immune response seems to be the result mainly of the preferential migration of activated cells back to their inductive sites. The aim of this report was to demonstrate, in a model of secondary immunodeficiency in Wistar rats (severely protein deprived at weaning and refed with casein 20%; group R21), that the oral administration of Thymomodulin (group:R21TmB) has different effects on gut and BALT (Bronchus-associated lymphoid tissue). Tissue sections (5 mu) were studied by immunohistochemistry 1). The oral administration of Thymomodulin restores only in gut Lamina propria (LP) the IgA B and CD4 T cell populations to control levels. The CD8a and CD25 subpopulations do not vary in gut as they return to control levels when refed with 20% casein diet. All the populations mentioned above remained decreased even after receiving Thymomodulin by the oral route. However, the same behaviour was observed for the TCR delta T cells that were decreased and return to normal levels in both mucosae by the effect of the immunomodulator; 2) when studying the iIEL (intestinal intraepithelial lymphocytes) CD8 alpha, CD25 and TCR gamma delta T cells, that were increased in R21, return to control levels in R21TmB. In BALT intraepithelium CD8 alpha and CD25 T cells remained decreased, while only TCR gamma delta T cells (increased in R21) return to control values. CONCLUSIONS: 1) there exists a compartmentalisation between both mucosae, as T CD4+ and IgA B+ cells are restored by TmB only in gut; 2) only those iIEL involved in inflammation (CD8 alpha+/CD25+ and TCR gamma delta+/CD25+) are normalised by means of the Thymomodulin 3) however, in BALT,only TCR gamma delta+ T cells are restored 4) the oral administration of the present immunomodulator may be useful as a therapeutic agent, although the preferential survival in the tissue of initial stimulation is the major factor in the preferential distribution of activated cells.