Marcílio Hubner de Miranda Neto

Morphoquantitative effects of acute diabetes on the myenteric neurons of the proximal colon of adult rats

The effects of acute diabetes on the density and size of the myenteric neurons of the proximal colon of adult rats were investigated. The injection of streptozotocin was followed by a period of observation of seven days, during which the diabetic animals showed weight loss, excessive food and water intake, large urinary debt and hyperglicemia. The whole-mounts from the proximal colon were stained with the techniques of Giemsa and of the NADH-diaphorase, and the employment of these techniques made it possible to verify a decrease on the neuronal density and on the cell body size of the myenteric neurons in the colon of the diabetic rats. These observations were discussed in terms of the pathophysiology of the diabetes and the experimental protocol.

Terminal ileum submucous plexus: Study of the VIP-ergic neurons of diabetic rats treated with ascorbic acid

The aim of this study was to evaluate the effect of the ascorbic acid (AA) supplementation on the neurons that produce the vasoactive intestinal peptide (VIP) in the submucous plexus of the ileum of rat, four months after the induction of experimental diabetes mellitus with streptozotocin. Three groups of rats were used: C - control, D - diabetic, DA - diabetic receiving AA. We have measured the immunoreactivity and area of 80 cellular bodies of VIP-ergic neurons from each studied group. In the diabetic animals, we have observed hyperphagia, polydipsia, and an increase of glycemia and glycated hemoglobin. The VIP-ergic neurons have presented an increase of their immunoreactivity and the highest profiles when compared to the other groups. In the diabetic animals supplemented with AA it has been observed a small reduction in the glycemia and the water and food intake. We have also noticed smaller immunoreactivity in their VIP-ergic neurons, similar to what we have observed in the control group animals (group C).

Immunohistochemical study of vasoactive intestinal peptide (VIP) enteric neurons in diabetic rats supplemented with L-glutamine

Abstract The purpose of this work was to study the area of the varicosities of nerve fibers of myenteric neurons immunoreactive to vasoactive intestinal peptide (VIP-IR) and of the cell bodies of VIP-IR submucosal neurons of the jejunum of diabetic rats supplemented with 2% L-glutamine. Twenty male rats were divided into the following groups: normoglycemic (N), normoglycemic supplemented with L-glutamine (NG), diabetic (D) and diabetic supplemented with L-glutamine (DG). Whole-mounts of the muscle tunica and the submucosal layer were subjected to the immunohistochemical technique for neurotransmitter VIP identification. Morphometric analyses were carried out in 500 VIP-IR cell bodies of submucosal neurons and 2000 VIP-IR varicosities from each group. L-Glutamine supplementation to the normoglycemic animals caused an increase in the areas of the cell bodies (8.49%) and varicosities (21.3%) relative to the controls (P < 0.05). On the other hand, there was a decrease in the areas of the cell bodies (4.55%) and varicosities (28.9%) of group DG compared to those of group D (P < 0.05). It is concluded that L-glutamine supplementation was positive both to normoglycemic and diabetic animals.

STUDY OF THE MYENTERIC PLEXUS OF THE ILEUM OF RATS SUBJECTED TO PROTEIC UNDERNUTRITION

Con el objetivo de verificar los efectos de la desnutricion proteica sobre el plexo mienterico del ileon, fueron utilizados 20 ratas del linaje Wistar, cuyas madres fueron desnutridas en los periodos de gestacion y/o lactacia sometidas a sacrificio a los 60 dias de edad. Se realizaron preparados de membrana del ileon tenidos con GIEMSA, para observacion de las neuronas mientericas y posteriores analisis y cuantificacion. Verificamos que la desnutricion proteica no provoca reducion en el numero de neuronas mientericas por cm2 de ileon, y que las neuronas medias con basofilia intermediaria predominan en todos los grupos

Morphologic and quantitative study of the myenteric neurons of the jejunum of malnourished rats (Rattus norvegicus)

We studied the effects of maternal proteic desnutrition on the neurons of the myenteric plexus of the jejunum of rats from Rattus norvegicus species. It was used litters of female rats which received diet with normal proteic level during gestation and lactation (group NN), normal diet during gestation and hypoproteic diet during lactation (group ND); hypoproteic diet during gestation and normal diet during lactation (group DN); hypoproteic diet during both gestation and lactation (group DD). After weaning all the animals received diet of normal proteic level until the 60th day of age, when they were killed. The jejunum of the animals was subjected to whole-mount preparations stained by the method of Giemsa and used for the morphologic and quantitative analyses of the neurons of the myenteric plexus. We verified that maternal proteic malnutrition does not cause decrease on the number of myenteric neurons per unit area of jejunum in rats, but elicits mechanisms which assure that, when the animal again receives normal proteic level diet (22%) there occurs storage of proteic material on the cytoplasm of the neurons, thus rendering them larger and strongly basophylic.

Nucleopolyhedrovirus: scanning electron microscopy technique

A simplified methodology was developed to study the geometric form of multiple Bombyx mori Nucleopolyhedrovirus by scanning electron microscopy. The virus belongs to Baculoviridae family and was isolated from the silkworm Bombyx mori (L.) (Lepidoptera: Bombycidae). The polyhedra of Nucleopolyhedrovirus were obtained from the filtrate, inoculum and hemolymph of the silkworm experimentally infected with nuclear polyhedra. This material was placed on stubs, where a copper tape was previously adhered. After dry at room temperature the virus was covered with carbon and gold. Scanning electron microscopy analysis revealed a well defined morphology for the polyhedra of multiple Bombyx mori Nucleopolyhedrovirus, making possible the mathematical study that identified it as a truncated octahedron. The form of the polyhedron can present taxonomic value, once it is specific for each viral lineage.

Effects of Insulin Treatment on HuC/HuD, NADH Diaphorase, and nNOS-Positive Myoenteric Neurons of the Duodenum of Adult Rats with Acute Diabetes

We carried out this investigation with the purpose of verifying whether insulin treatment prevents changes in the density of myoenteric neurons of the duodenum of Wistar rats with streptozotocin short-term diabetes. The animals from the diabetic group (D) lost more weight than the controls (group C), while the insulin treatment (group T) prevented weight loss in three animals and increased visceral fat in all of the animals of this group. Insulin treatment did not prevent the early loss of HuC/HuD myoenteric neurons. The density of nNOS-positive neurons did not change significantly in groups D and T. The density of NADHd-positive neurons in these groups was greater than in group C, indicating that short-term diabetes increases the activity of respiratory chain enzymes.

Quantitative Study of the Myenteric Plexus of the Descending Colon of Young Rats Subjected to Intense Protein Deficiency

Estudiamos los efectos cronicos de una dieta severamente hipoproteica sobre los aspectos cuantitativos del plexo mienterico del colon descendente de ratones jovenes. 18 ratones fueron divididos en dos grupos, a uno de estos grupos se le dio racion con contenido proteico del 26% (control) y al otro, racion con contenido proteico del 4%. Se mantuvo el balance vitaminico y mineral, durante 12 semanas. Elaboramos los preparados de membrana del colon descendente y marcamos las neuronas del plexo mienterico con Giemsa y NADPH-diaforasa. Los ratones del grupo experimental presentaron deficit de peso corporal (54,23%) y del area del colon descendente (48,14%); ademas, observamos que no hubo alteracion en el numero total de neuronas en todo el colon; sin embargo, hubo una disminucion en la marcacion de neuronas NADPH-diaforasa positivas (37,80%). Los resultados son discutidos, respecto a la prioridad que ciertos tipos celulares pudiesen tener, con la menor disponibilidad de nutrientes

Regional differences in the number and type of myenteric neurons in the descending colon of rats

The purpose of this study was to analyze the neuronal density of the myenteric plexus of the intermediate and antimesocolic regions of the descending colon of rats. Whole-mounts were stained with three different techniques of neuronal evidenciation. Through counts of the number of neurons in an area of 6.64 mm under light microscopy, we found 1,271 +/- 227.54 neurons with Giemsa in the intermediate region and 1,234 +/- 225.92 neurons in the antimesocolic region; with the NADH-diaphorase technique we found 530 +/- 92.97 neurons in the intermediate region and 539 +/- 146.72 neurons in the antimesocolic region; and through the NADPH-diaphorase histochemistry, we found 417 +/- 34.42 neurons in the intermediate region and 547 +/- 84.01 neurons in the antimesocolic region. We conclude that there is a variation in the density of NADPH-diaphorase positive neurons in the intestinal circumference; that the NADH-diaphorase positive neuronal subpopulation represented 42.7% of that stained with Giemsa; and that the NADPH-diaphorase positive neurons represented 37.8% of the whole myenteric population.

Neurônios NADH-diaforase positivos do jejuno de ratos adultos (Rattus norvegicus) desnutridos: aspectos quantitativos

We aim at contributing with information on the quantitative aspects of the NADH-diaphorase positive myenteric neurons of the jejunum of adult rats subjected to protein desnutrition. Ten rats aging 90 days were divided into two groups: control (n=5, ±278 g) and disnurtured (n=5, ±280 g). In the following 120 days, the rats from the control group had chow with 22% protein level, and those from the disnurtured group, with 8% protein level. After this period, the control rats weighted ±394.4g and the disnurtured ±273.5g. The jejunum was subjected to the histochemical technique of the NADH-diaphorase to stain nerve cells in whole-mounts. The neurons found in 80 microscopic fields of both groups were counted. In the control ±674.6 neurons were observed, and ±1326.8 neurons were counted in the disnurtured group. The low-protein diet did not alter the organization of the neurons, but led to a smaller body growth in the disnurtured animals, preventing neuronal dispersal and leading to a greater density per mm2.