Long-term and low dose oral malathion exposure causes morphophysiological changes in the colon of rats.

BACKGROUND: Malathion (MAL) is an organophosphate insecticide that inhibits cholinesterases, used to control pests in agriculture and to combat mosquitoes that transmit various arboviruses. As acetylcholine is one of the major neurotransmitters of the enteric nervous system (ENS), humans exposed to MAL by ingestion of contaminated food and water can develop symptoms due disfunction of the gastrointestinal tract. Although the deleterious effects after exposure to high doses are recognized, little is known about the long-term and low-dose effects of this pesticide on the structure and motility of the colon. AIMS: to evaluate the effects of prolonged oral exposure to low levels of MAL on the wall structure and colonic motility parameters of young rats. MAIN METHODS: The animals were divided into three groups: control, and groups that received 10 or 50 mg/kg of MAL via gavage for 40 days. The colon was collected for histological analysis and analysis of the ENS through the evaluation of total neurons and subpopulations of the myenteric and submucosal plexuses. Cholinesterase activity and functional analyzes of the colon were evaluated. KEY FINDINGS: MAL treatments (10 and 50 mg/Kg) reduced the butyrylcholinesterase activity, and caused enlargement of faecal pellets, atrophy of muscle layers and several changes in neurons of both myenteric and submucosal plexi. Considering colonic contraction, MAL (50 mg/Kg) increased the number of retrograde colonic migratory motor complexes. SIGNIFICANCE: The long-term exposure to low doses of MAL affects colonic morphophysiology, which highlights the need to intensify control and care in the use of this pesticide.

Myenteric neuroprotective role of aspirin in acute and chronic experimental infections with Trypanosoma cruzi.

BACKGROUND: Experimental and clinical studies have shown that myenteric neuron cell death during infection with Trypanosoma cruzi mainly occurs in the esophagus and colon, resulting in megaesophagus and megacolon, respectively. Evidence suggests that the cyclooxygenase enzyme (COX) is involved in the T. cruzi invasion process. The use of low-dose aspirin (ASA), a COX-1/COX-2 inhibitor, has been shown to reduce infection with T. cruzi. Therefore, in this study, we evaluated the effects of treatment with low-dose ASA on myenteric colonic neurons during murine infection with T. cruzi. METHODS: Swiss mice were assigned into groups treated with either phosphate-buffered saline or low doses of ASA during the acute phase (20 mg/kg ASA) and chronic phase (50 mg/kg ASA) of infection with the Y strain of T. cruzi. Seventy-five days after infection, colon samples were collected to quantify inflammatory foci in histological sections and also general (myosin-V+ ), nitrergic, and VIPergic myenteric neurons in whole mounts. Gastrointestinal transit time was also measured. KEY RESULTS: Aspirin treatment during the acute phase of infection reduced parasitemia (P<.05). Aspirin treatment during the acute or chronic phase of the infection reduced the intensity of inflammatory foci in the colon, protected myenteric neurons from cell death and plastic changes, and recovered the gastrointestinal transit of mice infected with T. cruzi (P<.05). CONCLUSION & INFERENCES: Early and delayed treatment with low-dose ASA can reduce the morphofunctional damage of colonic myenteric neurons caused by murine T. cruzi infection.

Infecção toxoplásmica causa hipertrofia da parede do cólon de frangos / Toxoplasmic infecction causes hipertrophy of the chicken colon wall

Estudaram-se os efeitos da infecção toxoplásmica sobre a morfometria da parede intestinal, a distribuição de fibras colágenas e a dinâmica de mucinas secretadas no cólon de frangos. Foram utilizados 16 frangos machos de linhagem comercial, com 26 dias de idade. As aves foram distribuídas, aleatoriamente, em três grupos (G). As do G1 não receberam inóculo e se caracterizaram como grupo-controle; nas do G2, foram inoculados cistos teciduais da cepa ME49 de Toxoplasma gondii; e nos G3, oocistos da cepa M7741 de T. gondii. Após 60 dias da inoculação, os animais foram sacrificados para coleta do cólon, o qual foi submetido à rotina de processamento histológico. Em G2 e G3, observou-se hipertrofia da parede do cólon, contudo não houve alteração na proporção do número de células caliciformes e de enterócitos presentes no epitélio intestinal.

The effects of toxoplasmosis on the intestinal wall morphometry, the distribution of collagen fibers, and the dynamic of mucins secreted in the chicken colon were analyzed. Sixteen 26-day-old male Cobb chicks (Gallus gallus) were randomly distributed into three groups (G1, G2, and G3). G1 received no inoculums and characterized the control group, G2 was inoculated with tissue cysts of ME49 strain of Toxoplasma gondii, and G3 was inoculated with oocytes of M7741 strain of T. gondii. After 60 days of inoculation, the animals were slaughtered and had their colon collected and submitted to histological processing. Transversal cuts (4μm) were stained with Hematoxylin-Eosin (HE), Periodic Acid Schiff (PAS), Alcian Blue pH 2.5, Alcian Blue (AB) pH 1.0, and Azan. G2 and G3 animals showed hypertrophy of the colon wall, but the proportion between the number of goblet cells and enterocytes present in the intestinal epithelium was not altered.

Hypertrophy of NADH-diaphorase positive myenteric neurons in rat jejunum after acute infection caused by Toxoplasma gondii

Toxoplasmosis, a globally distributed feline-associated zoonosis caused by the protozoan Toxoplasma gondii, affects birds and mammals, including humans. This study assesses the consequences of acute T. gondii infection for NADH-diaphorase positive myenteric neurons in rat jejunum. Ten male Wistar rats (Rattus norvegicus) were divided into two groups: G1 (n = 5) and G2 (n = 5). Animals from G2 were orally inoculated with 500 genotype III (M7741) T. gondii oocysts. Twenty-four hours after inoculation, the animals were euthanized and had their jejuna removed, through laparotomy, and measured (length and width) to calculate their areas. Intestinal segments were submitted to NADH-diaphorase histochemistry to evidence the most metabolically active subpopulation of myenteric neurons. No changes were found in body weight; intestinal length, width or area; or neuron population density. Increase of body cell area and cytoplasm and decrease of nuclear area of the myenteric neurons of infected animals were observed by morphometric analysis.

The effect of both protein and vitamin b complex deficiency on the morphoquantitative features of the myenteric plexus of the ascending colon of adult rats / Efeito da carência de proteínas e vitaminas do complexo b sobre aspectos morfoquantitativos do plexo mioentérico do colo ascendente de ratos adultos / Efecto de la carencia de proteínas y vitaminas del complejo b sobre aspectos morfo-cuantitativos del plexo mioentérico del regazo ascendiente en ratones adultos

O objetivo deste estudo foi estudar os efeitos da desnutrição protéica e da carência de vitaminas do complexo B sobre o plexo mioentérico do colo ascendente de Rattus norvegicus. Vinte ratos foram divididos em dois grupos, sendo que, para um dos grupos foi oferecida ração com teor protéico de 22% (controle) e, para outro, ração com teor protéico de 8% com menor teor de vitaminas do complexo B, durante 120 dias. Coramos os preparados de membrana do colo ascendente pelo método de Giemsa e pela técnica da NADH-diaforase. Os ratos desnutridos apresentaram peso corporal 14,8% menor que o grupo controle, média da área do colo 54,2% menor, e a média da densidade neuronal foi 26,7% maior com a técnica de Giemsa e 27% com a técnica da NADH-diaforase. Como a redução da área não foi acompanhada por um aumento inversamente proporcional na densidade de neurônios, sugere-se que a condição imposta causou perda de neurônios mioentéricos.

This study was performed in order to study the effects of protein desnutrition and vitamin B complex deficiency on the myenteric plexus of the ascending colon of Rattus norvegicus. Twenty rats were divided into two groups; one had been fed with a 22%-protein-level ration, and the other with a 8%-protein-level without vitamin-B-complex supplementation, for 120 days. The whole-amounts of the ascending colon were stained with either Giemsa or NADH-diaphorase technique. The disnurtured rats showed a 14.8% smaller body weight than the control group, and the area of colon of the sample group was 54.2% smaller. The average neuronal density was 26.7% greater with the Giemsa technique and 27% greater with the NADH-diaphorase technique. As the decrease in area was not accompanied by an inversely proportional increase in neuronal density, it is suggested that the experimental condition led to a myenteric neuron loss.

El objetivo de este estudio fue analisar los efectos de la desnutrición proteica y de la carencia de vitaminas del complejo B sobre el plexo mioentérico del regazo ascendiente de Rattus norvegicus. Veinte ratones fueron divididos en dos grupos, siendo que, para uno de los grupos se ofreció ración con contenido proteico de 22% (control) y, para el otro, ración con contenido proteico de 8% con menor contenido de vitaminas del complejo B, durante 120 días. Coloreamos los preparados de membrana del regazo ascendiente por el método de Giemsa y por la técnica de la NADH-diaforasis. Los ratones desnutridos presentaron peso corporal 14,8% menor que el grupo control, promedio del área del regazo de 54,2% menor, y el promedio de la densidad neuronal fue 26,7% mayor con la técnica de Giemsa y 27% con la técnica de la NADH-diaforasis. Como la reducción del área no fue acompañada por un aumento inversamente proporcional en la densidad de neuronas, se cree que la condición impuesta causó pérdida de neuronas mioentéricos.

Biometric and food consumption parameters of rats subjected to hypoproteic and hipercaloric diet / Parâmetros biométricos e de consumo alimentar de ratos submetidos à dieta hipoprotéica e hipercalórica / Parámetros biométricos y de consumo alimentar de ratones sometidos a la dieta hipoprotéica e hipercalórica

A carência de proteínas, causando Kwashiorkor, é o tipo de má-nutrição mais prevalente, pois fontes de alimentos protéicos, geralmente, são mais onerosas. Para estudos experimentais, o rato tem sido o principal modelo para avaliar as conseqüências de ingestão de dietas com diferentes teores protéicos, contudo ainda não estão claros os níveis de severidade dessas dietas para essa espécie. Nesse sentido, propõe-se avaliar a severidade de uma dieta hipoprotéica a 4% para ratos jovens. Para tanto, utilizaram-se 30 ratos Wistar (90 dias de idade), os quais foram divididos em dois grupos: controle (GC) e experimental (GC). O GC recebeu dieta normoprotéica, enquanto o GE recebeu dieta com 4% de teor de proteínas, ambos, durante 12 semanas. No final do experimento, avaliaram-se o peso, o crescimento, a massa gorda e massa magra dos animais. Os animais do GE não ganharam peso, tiveram retardo no crescimento, formaram menos massa gorda e menos massa muscular.

ABSTRACT: The protein lack causing Kwashiorkor is the most prevalent kind of malnutrition, because the food sources of proteins are usually more expensive. For experimental investigations, the rat has provided the primary model to evaluate the consequences of the ingestion of diets with different protein levels; however, the degrees of severity of these diets for thesespecies are still not clear. In this sense, we aimed at evaluating the severity of a 4%-hypoproteic diet on young rats. We used30 Wistar rats (90 days old), which were divided in two groups: control (CG) and experimental (EG). CG rats were fed with normoprotein chow, while EG rats were fed with a chow having 4% protein, for 12 weeks. At the end of the experiment, we evaluated the weight, growth, and fat and lean masses of the animals. The rats from EG did not gain weight, they had growth retardation, and built less fat and muscle masses.

RESUMO: A carência de proteínas, causando Kwashiorkor, é o tipo de má-nutrição mais prevalente, pois fontes de alimentos protéicos, geralmente, são mais onerosas. Para estudos experimentais, o rato tem sido o principal modelo para avaliar as conseqüências de ingestão de dietas com diferentes teores protéicos, contudo ainda não estão claros os níveis de severidade dessas dietas para essa espécie. Nesse sentido, propõe-se avaliar a severidade de uma dieta hipoprotéica a 4% para ratos jovens. Para tanto, utilizaram-se 30 ratos Wistar (90 dias de idade), os quais foram divididos em dois grupos: controle (GC) e experimental (GC). O GC recebeu dieta normoprotéica, enquanto o GE recebeu dieta com 4% de teor de proteínas, ambos, durante 12 semanas. No fi nal do experimento, avaliaram-se o peso, o crescimento, a massa gorda e massa magra dos animais. Os animais do GE não ganharam peso, tiveram retardo no crescimento, formaram menos massa gorda e menos massa muscular.

Hematologic and biochemical parameters of rats subjected to hypoproteic and hipercaloric diet / Parâmetros hematológicos e bioquímicos de ratos submetidos à dieta hipoprotéica e hipercalórica / Parámetros hematológicos y bioquímicos de ratones sometidos a la dieta hipoprotéica e hipercalórica

A má-nutrição é um problema de saúde pública que ainda assola crianças e adultos no mundo inteiro, principalmente em países em desenvolvimento. A carência de proteínas, causando Kwashiorkor, é o tipo de má-nutrição mais prevalente, pois fontes de alimentos protéicos, geralmente, são mais onerosas. Uma dieta hipoprotéica causa alterações metabólicas num animal em intensidades diretamente proporcionais ao nível de depleção de proteínas, bem como o tempo em que o indivíduo permanece sob o estado de subnutrição. Nesse sentido, propõe-se avaliar a severidade de uma dieta hipoprotéica a 4% para ratos jovens. Utilizam-se 30 ratos Wistar (90 dias de idade), divididos em grupo controle (15) e experimental (15). O GC recebeu dieta normoprotéica, enquanto o GE recebeu dieta com 4% de teor de proteínas, ambos durante 12 semanas. No final do experimento, sangue foi coletado para realização de hemograma e dosagem de atividade de fosfatase alcalina, alanina aminotrasferase, além da concentração de proteínas totais e frações, colesterol total, triglicerídeos, uréia, ácido úrico, T3, T4 e aminoácidos plasmáticos. Os animais do GE demonstraram menor atividade defosfatase alcalina no sangue, anemia microcítica normocrômica, hipoproteinemia, hipoglobulinemia, reduação na concentração plasmática de triglicerídeos, aumento da concentração plasmática de T3 e T4 e diminuição da concentração plasmática dos seguintes aminoácidos: metionina, fenilalanina, valina, leucina e isoleucina.

ABSTRACT: Malnutrition is a public health issue which still affects children and adults all over the world, especially in developing countries. Protein defi ciency causing Kwashiorkor is the most prevalent type of malnutrition, because protein-rich foods are generally expensive. A hypoproteic diet causes metabolic alterations in an animal which are directly proportional to the degree of protein depletion, as well as to the duration of the malnutrition. In this sense, we proposed to evaluate the severity of a 4%-hypoproteic diet in young rats. We used 30 Wistar rats (90 days of age), divided in control (CG, n=15) and experimental (EG, n=15) groups. CG was fed with a normoprotein chow, while EG was fed with a diet having 4% protein, for 12 weeks. At the end of the experiment, blood was collected for determination of the hemogram, activities of alkaline phosphatase and alanine aminotransferase, and concentration of total and fractional proteins, total cholesterol, triglycerides,urea, uric acid, T3, T4 and plasma aminoacids. The animals from EG had lower activity of the alkaline phosphatase enzyme in blood, normochromic microcytic anemia, hypoproteinemia, hypoglobulinemia, decreased plasma triglyceride concentration, increased plasma concentrations of T3 and T4, and decreased plasma concentrations of the following aminoacids: methionine, phenylalanine, valine, leucine and isoleucine

RESUMEN: La mala nutrición es un problema de salud pública que todavía aniquila niños y adultos en el mundo entero, principalmente en países en desarrollo. La falta de proteínas, causando Kwashiorkor, es el tipo de mala nutrición más común, pues fuentes de alimentos proteicos, generalmente, son más caras. Una dieta poco proteica causa alteraciones metabólicas en un animal en intensidades directamente proporcionales al nivel de depleción de proteínas, así como el tiempo en que el individuo queda bajo el estado de baja nutrición. En ese sentido, proponemos evaluar la severidad de una dieta de bajo contenido proteico al 4% para ratones jóvenes. Utilizamos 30 ratones Wistar (90 días de edad), divididos en grupo control (15) y experimental (15). El GC recibió dieta normoproteica, mientras el GE recibió dieta con el 4% de cantidad de proteínas, ambos durante 12 semanas. Al fi nal del experimento, sangre fue recolectado para realización del examen de la sangre y cantidad de actividad de fosfatase alcalina, alanina aminotrasferase, además de la concentración de proteínas totales y fracciones, colesterol total, triglicerídeos, urea, ácido úrico, T3, T4 y aminoácidos plasmáticos. Los animales del GE demostraron menor actividad de fosfatase alcalina en la sangre, anemia microcítica normocrómica, hipoproteinemía, hipoglobulinemia, reducción en la concentración plasmática de triglicerídeos, aumento de la plasmática de T3 y T4 y disminución de la concentración plasmática de los siguientes aminoácidos: metionina, fenilalanina, valina, leucina y isoleucina