Quantitative analysis of the distribution of the myenteric plexus in the rabbit large intestine.

Rabbit large intestine has a segment-specific morphology and motility. However, the morphological features of the myenteric plexus, which controls intestinal motility, have not been characterized in each large intestinal segment. We investigated the myenteric plexus morphology in the rabbit large intestine using protein gene product 9.5 immunohistochemistry in whole-mount preparations. The tenial part of the first and second segments of the proximal colon had the most well developed myenteric plexus, while the caecum had the least. These findings suggest different neuronal control over the motility of each intestinal segment, thereby providing a fundamental understanding of the rabbit enteric nervous system.

Morphological changes of the myenteric plexus at different gut segments of human fetuses.

The neural crest cell-derived enteric nervous system (ENS) is the intrinsic innervation of the gastrointestinal tract (GIT) which consists of neurons and enteric glia cells in the myenteric ganglia and forming plexus. The ENS consists mainly of submucosal and myenteric plexuses. It has various functions on the GIT, which include control of local blood flow, motility, mucosal transport, secretions, immune modulation as well as endocrine functions and coordinated contractile activity of smooth muscle. The knowledge on the development of the innervations at different segments of the gut in humans from 11 to 26 weeks of gestation (WG) may help in understanding the pathophysiology of various congenital diseases affecting the ENS. The aim of this study is to determine the morphology of the myenteric plexus in the esophagus, ascending colon and sigmoid colon at various weeks of gestation. Tissue samples from 10 naturally terminated fetuses aged 11-26 WG were processed for hematoxylin and eosin staining and immunohistochemistry assay. The neurons, enteric glia, the smooth muscle were visualized using PGP9.5, Vimentin and S-100 antibodies. The number of neurons and enteric glial cells appeared lowest in the esophagus than the ascending and sigmoid colon. The myenteric ganglion was closely apposed to each other, forming a continuous arch along the entire circumference of gut sections of ascending and sigmoid colon but the myenteric ganglia in the esophagus was thinly populated and widely spread in the fetus at 13 WG. As the fetal gastrointestinal tract grew in diameter and length, the myenteric ganglia became discernible.

Quantification of the neurons of myenteric plexus of the bat molossus rufus / Quantificação dos neurônios do plexo mientérico de morcegos da espécie Molossus rufus

There are no studies that characterize the enteric nervous system (ENS) bats. The organization and density of myenteric neurons may vary according to the animal species, as well as the segment of the digestive tube considered. The nitric oxide is one of the key neurotransmitters present in the myenteric neurons, acting as a mediator in the smooth muscle relaxation. These neurons are evidenced by immunohistochemistry of nitric oxide synthase (NOS) or by NADPH-diaphorase histochemistry. In this sense, this study aimed to characterize the total neuronal population and subpopulation NADPH-d+ of the myenteric plexus present in the jejunum of the insectivore species Molossus rufus quantitatively. Five specimens were collected of M. rufus in a buffer area of the "Reserva Biológica das Perobas" in the microregion of Cianorte/PR. After the euthanasia, in a chamber saturated with isoflurane, segments were collected from the small intestine corresponding to the jejunum intended for two techniques for neuronal marking, Giemsa and NADPH-diaphorase, and a fragment to the histological technique of hematoxylin-eosin and Masson's trichrome. All the procedures were approved by the "Comitê de Ética no Uso de Animais Unipar" (CEUA - protocol No. 34347/2017) and the "Instituto Chico Mendes de Conservação da Biodiversidade" (ICMBio - protocol No. 60061-1) The histological sections allowed to highlight the location of the myenteric plexus between the longitudinal and circular layers of the muscular tunic. The myenteric plexus had an average of total neuronal population (neurons Giemsa+) of 279.23 neurons/mm2, being the nitrergic neurons (neurons NADPH-d+) represented 20.4% of this total population, with an average of 58.14 neuron/mm2. Therefore, the collected data are consistent with previous studies in other mammalian species concerning the location of the myenteric plexus, as well as the neural myenteric proportion NADPH-d+ compared with the population of neurons Giemsa+. The gaps in the knowledge of ENS of bats limits comparative intraspecific and interspecific studies.(AU)

Não há estudos que caracterizem o sistema nervoso entérico (SNE) destes animais, configurando uma lacuna no conhecimento quanto à biologia destes indivíduos. A organização e densidade dos neurônios mientéricos podem variar de acordo com a espécie animal bem como o segmento do tubo digestório considerado. O óxido nítrico é um dos principais neurotransmissores presentes nos neurônios mientéricos, atuando como mediador no relaxamento do músculo liso gastrointestinal, de modo que estes neurônios são evidenciados igualmente pela imunohistoquímica da óxido nítrico-sintase (NOS) ou pela histoquímica da NADPH-diaforase. Neste sentido, objetivou-se caracterizar quantitativamente a população neuronal total e subpopulação NADPH-d+ do plexo mientérico presente no jejuno da espécie Molossus rufus de hábito alimentar insetívoro. Foram coletados cinco espécimes de M. rufus em área de amortecimento da Reserva Biológica das Perobas na microrregião de Cianorte/PR. Após a eutanásia, em câmara saturada com isoflurano, foram coletados segmentos do intestino delgado correspondentes ao jejuno destinados a duas técnicas para marcação neuronal, Giemsa e NADPH-diaforase e, um fragmento para a técnica histológica de hematoxilina-eosina e tricômio de Masson. Todos os procedimentos realizados foram aprovados pelo Comitê de Ética no Uso de Animais da Unipar (CEUA - protocolo nº 34347/2017) e pelo Instituto Chico Mendes de Conservação da Biodiversidade (ICMBio - protocolo nº 60061-1) Os cortes histológicos possibilitaram evidenciar a localização do plexo mientérico entre os estratos longitudinal e circular da túnica muscular. Neurônios Giemsa+ apresentaram uma média de 279,23 neurônios/mm2, já os neurônios nitrérgicos apresentaram em média 20,4% da população neuronal mientérica total, sendo evidenciados 58,14 neurônios NADPH-d+/mm2. Portanto, os dados coletados mostram-se condizentes com estudos anteriores em outras espécies de mamíferos quanto à localização do plexo mientérico, bem como, a proporção neuronal mientérica NADPH-d+ comparada com a população de neurônios Giemsa+. As lacunas existentes quanto ao conhecimento do SNE de morcegos limita possíveis inferências em comparativo intraespecífico e interespecífico.(AU)

Comparative study of the distribution of NOS-positive neurons in pigeon intestine.

Nitric oxide (NO) plays an important role in regulating gut motility, mucosal barrier function and secretions in the enteric nervous system. Nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) staining has been used to identify nitrergic neurons of the enteric nervous system in different species. However, NADPH-d staining lacks specificity because it also reflects the presence of enzymes other than nitric oxide synthase (NOS). Therefore, NOS immunohistochemistry techniques are needed to test for nitrergic neurons in the avian gut. In the present work, the morphology, density and size of NOS-positive neurons in the duodenum, jejunum, ileum, caecum and rectum myenteric plexus of adult pigeons were investigated using NOS immunohistochemistry and whole-mount preparations techniques. The density of NOS-positive ganglion was highest in the ileum, similar to the caecum and rectum, and the lowest staining levels were observed in the duodenum. The staining intensity of NOS-positive neurons in the duodenum, jejunum and ileum was dark, followed by the rectal regions, with weak staining in the caecum. These results suggested that NOS immunohistochemistry and whole-mount preparation techniques provide an effective assessment method of the ganglia in the pigeon intestinal myenteric nerve plexus and are more accurate for cell counting compared with conventional sections.

Regional variations in the number distribution of intrinsic myenteric neurons and coinnervated motor endplates on the striated muscles in the rat esophagus.

The roles of intrinsic neurons and the significance of the coinnervated striated muscles in the esophagus are unclear. We examined the number distribution of intrinsic neurons and coinnervated motor endplates on the striated muscles in the rat esophagus using immunohistochemistry to investigate whether these neurons and coinnervated striated muscles may be relevant to the local control of esophageal motility. The number of PGP9.5-positive neurons was higher in the cervical esophagus (segment 1) and gradually decreased toward the aboral, with a moderate increase in the abdominal (segment 5). This pattern was similar to that of NOS-positive neurons, while the number of ChAT-positive neurons decreased toward the aboral, but it was not significantly different among segments 3 to 5. The number of ChAT-positive motor endplates increased toward the aboral, with the highest number in segment 5. The proportion of coinnervated motor endplates was approximately 80% in segments 1 to 4, but approximately 66% in segment 5. NPY-IR was localized in some nerve terminals among the smooth muscles of the muscularis mucosa and some NOS- or ChAT-positive esophageal intrinsic neurons. ENK-8-IR was found in some NOS- or ChAT-positive intrinsic neurons, and nerve terminals surrounding intrinsic neurons in the esophagus, but not in motor neurons at the NA or DMV. This study suggests that regional variations in the number of intrinsic neurons and coinnervated striated muscles in the rat esophagus may be involved in local regulations of esophageal motility, and that the rat esophageal intrinsic neurons may contain, at least, motor neurons and interneurons.

Enteric neurons of the esophagus: an immunohistochemical study using donated elderly cadavers.

PURPOSE: To describe and discuss the normal anatomy and function of enteric neurons in the esophagus of aged individuals. METHOD: We examined ganglion cells in esophagus specimens obtained from 15 elderly cadavers without any macroscopic pathology in the mediastinum and abdomen. Neuronal nitric oxide synthase and vasoactive intestinal polypeptide were used as parasympathetic nerve markers, and tyrosine hydroxylase as a sympathetic nerve marker. RESULTS: The thoracic and abdominal esophagus contained a well-developed myenteric nerve plexus (S100 protein-positive area) in the intermuscular layer: 0.02-0.03 mm2 per 1-mm length of the circular esophageal wall. The cervical esophagus usually contained no ganglion cells. The number of parasympathetic ganglion cells was maximal in the upper or middle thoracic esophagus (mean 18-23 cells per section), whereas sympathetic cells were considerably less numerous at any sites (mean 1-3 cells). CONCLUSION: In comparison with previous data from elderly cadavers, the esophagus carried much fewer ganglion cells than the intestine and colon; sympathetic cells were particular less numerous. Esophageal smooth muscle exhibits a unique mode of peristalsis characterized by a rebound contraction with a long latency after stimulation. This type of peristalsis appears to be regulated by inhibitory, nNOS-positive nerves with a sparse distribution, which seems to account for the long-span peristalsis unique to the esophagus. The extreme sparsity of ganglion cells in the cervical esophagus suggests that enteric neuron-integrated peristalsis, like that in the intestine and colon, is unlikely. Surgical treatment of the esophagus is likely to change or impair these unique features.

Quantitative morphometric analysis of the myenteric nervous plexus ganglion structures along the human digestive tract.

BACKGROUND/AIM: All the functions of the digestive system are controlled, guided and initiated by the autonomic nervous system. A special part of this system placed in the wall of the gastrointestinal tract is known as the enteric or metasympathetic nervous system. The aim of this study was to analyse myenteric nervous plexus in different parts of the digestive tract. METHODS: We examined the myenteric nervous plexus of the esophagus, stomach, duodenum, jejunum, ileum, transverse colon and rectum in tissue samples taken from 30 cadavers of persons aged 20-84 years. After standard histological processing sections were stained with hematoxylin-eosin, cresyl violet (CV) and AgNO3 method. Multipurpose test system M42 was used in morphometric analysis. The results were analyzed by t-test and analysis of variance. RESULTS: The number of neurons per cm² surface was the lowest in the esophagus (2.045 ± 310.30) and the largest in the duodenum (65,511 ± 5,639). The statistical processing showed significant differences (P < 0.001) in the number of neurons between the esophagus and all other parts of the digestive tract. The maximal value of the average surface of the myenteric nervous plexus neurons was observed in the esophagus (588.93 ± 30.45 µm²) and the lowest in the stomach (296.46 ± 22.53 µm²). CONCLUSION: There are differences in the number of ganglion cells among different parts of the human digestive tract. The differences range from a few to several tens of thousands of neuron/cm2. The myenteric nervous plexus of the esophagus was characterized by a significantly smaller number of neurons but their bodies and nuclei are significantly larger compared to other parts of the digestive tract.

Region-specific differences in the human myenteric plexus: an immunohistochemical study using donated elderly cadavers.

PURPOSE AND METHODS: To identify site-dependent and individual differences in neuronal nitric oxide synthase (nNOS)-positive nerves of the myenteric plexus, we examined full-thickness walls of the stomach, pylorus, duodenum, ileum, colon, and rectum in 7 male and 8 female cadavers (mean ages, 80 and 87 years, respectively). RESULTS: The areas occupied by nNOS-positive nerve fibers in the myenteric plexus were fragmentary and overlapped with areas occupied by vasoactive intestinal polypeptide-positive fibers. The nNOS-positive fiber-containing areas per 1-mm length of intermuscular space tended to be larger at more anal sites, with positive areas four times greater in the rectum than in the stomach. Interindividual differences in rectal areas were extremely large, ranging from 0.017 mm(2) in one 80-year-old man to 0.067 mm(2) in another 80-year-old man. Similarly, the numbers of nNOS-positive ganglion cell bodies per 1-mm length in the rectum ranged from 4 to 28. These areas and numbers were weakly correlated (r = 0.62; p = 0.02). Interindividual differences in the rectum appeared not to depend on either age or gender. CONCLUSIONS: Anatomic studies using donated cadavers carried the advantage of obtaining any parts of intestine within an individual, in contrast to surgically removed specimens. We speculated excess control of evacuation with laxatives as one of causes of atrophy of the rectal myenteric plexus.

Nerve supply to the internal anal sphincter differs from that to the distal rectum: an immunohistochemical study of cadavers.

PURPOSE: Fecal incontinence is a common problem after anal sphincter-preserving operations. The intersphincteric autonomic nerves supplying the internal anal sphincter (IAS) are formed by the union of: (1) nerve fibers from Auerbach's nerve plexus of the most distal part of the rectum and (2) the inferior rectal branches of the pelvic plexus (IRB-PX) running along the conjoint longitudinal muscle coat. The aim of the present study is to identify the detailed morphology of nerves to the IAS. METHODS: The study comprised histological and immunohistochemical evaluations of paraffin-embedded sections from a large block of anal canal from the preserved 10 cadavers. RESULTS: The IRB-PX came from the superior aspect of the levator ani and ran into the anal canal on the anterolateral side. These nerves contained both sympathetic and parasympathetic fibers, but the sympathetic content was much higher than in nerves from the distal rectum. All intramural ganglion cells in the distal rectum were neuronal nitric oxide synthase-positive and tyrosine hydroxylase-negative and were restricted to above the squamous-columnar epithelial junction. Parasympathetic nerves formed a lattice-like plexus in the circular smooth muscles of the distal rectum, whereas the IAS contained short, longitudinally running sympathetic and parasympathetic nerves, although sympathetic nerves were dominant. CONCLUSIONS: The major autonomic nerve input to the IAS seemed not to originate from the distal rectum but from the IRB-PX. Injury to the IRB-PX during surgery seemed to result in loss of innervation to the major part of the IAS.

Morphometric analysis of muscularis proper and myenteric plexus of the normal human oesophagus. Age related changes.

BACKGROUND: Oesophagus is a muscular tube that transports food and liquids by coordinated contraction of its muscular lining led by stimuli from the nerve plexus. Its muscularis proper layer consists of muscle cells, connective tissue and myenteric plexus. The aim of our histomorphometric study was to reveal detailed characteristics of this layer, cell number, volume, orientation, properties of myenteric plexus as well as changes related to aging. MATERIALS AND METHODS: Oesophagus tissue samples from 17 male cadavers were taken from the cranial and thoracic parts. Samples were divided in 2 groups: younger(ages 21-45) and older (ages 66-78). The tissue was routinely processed,embedded and serially sectioned. Sections were stained with Masson-Goldner and Cresyl-violet dyes. Digital images were analysed with the image analysis software.Statistics were performed with SPSS software. RESULTS: The average thickness of the cranial part of the oesophageal wall and muscularis proper was 2590 µm and 1197 µm, respectively in the younger and 2453 µm and 1144 µm in the older group. Overall volume of the muscle tissue was slightly larger in the thoracic part, and in the younger group compared to the cranial part and the older group. The average number of the striated muscle cells per 100 µm in the cranial part was 771.5 and 749.7 in the younger and the older group, respectively. Striated cells were significantly less present only in the lower thoracic part of the oesophagus. In the older group,smaller striated muscle cells dominated over the larger ones. In the younger group, majority of the striated muscle cells were mid-sized. The thickness of the circular layer of muscularis proper was more affected by aging than the longitudinal one. Ganglion cells number was lower in the older group, but plexus area was unchanged. CONCLUSIONS: Aging affects muscularis proper and myenteric plexus of the oesophagus.Major differences can be observed in the striated muscle cells size, volume of the circular layer and number of the ganglionic cells in the myenteric plexus.

Organization of the innervation of the oesophagus and stomach in chinchilla (Chinchilla laniger, Molina).

Using the histochemical and histological techniques the morphology and topography of the autonomic plexuses of the oesophagus and stomach in chinchilla (Chinchilla laniger) was investigated. AChE-positive and adrenergic structures in the myenteric and submucosal plexus were observed. According to the results the cholinergic structures were formed by the different in shape network meshes, various size of the neurons agglomerations and nerve fibres. Adrenergic fibres were found. Density of these structures varied in different parts of the investigated organs. This study is the first attempt to localize the intramural autonomic plexuses in this species.

3-D imaging and illustration of mouse intestinal neurovascular complex.

Because of the dispersed nature of nerves and blood vessels, standard histology cannot provide a global and associated observation of the enteric nervous system (ENS) and vascular network. We prepared transparent mouse intestine and combined vessel painting and three-dimensional (3-D) neurohistology for joint visualization of the ENS and vasculature. Cardiac perfusion of the fluorescent wheat germ agglutinin (vessel painting) was used to label the ileal blood vessels. The pan-neuronal marker PGP9.5, sympathetic neuronal marker tyrosine hydroxylase (TH), serotonin, and glial markers S100B and GFAP were used as the immunostaining targets of neural tissues. The fluorescently labeled specimens were immersed in the optical clearing solution to improve photon penetration for 3-D confocal microscopy. Notably, we simultaneously revealed the ileal microstructure, vasculature, and innervation with micrometer-level resolution. Four examples are given: 1) the morphology of the TH-labeled sympathetic nerves: sparse in epithelium, perivascular at the submucosa, and intraganglionic at myenteric plexus; 2) distinct patterns of the extrinsic perivascular and intrinsic pericryptic innervation at the submucosal-mucosal interface; 3) different associations of serotonin cells with the mucosal neurovascular elements in the villi and crypts; and 4) the periganglionic capillary network at the myenteric plexus and its contact with glial fibers. Our 3-D imaging approach provides a useful tool to simultaneously reveal the nerves and blood vessels in a space continuum for panoramic illustration and analysis of the neurovascular complex to better understand the intestinal physiology and diseases.

3-D illustration of network orientations of interstitial cells of Cajal subgroups in human colon as revealed by deep-tissue imaging with optical clearing.

Morphological changes of interstitial cells of Cajal (ICC) have been proposed to characterize motility disorders. However, a global view of the network orientations of ICC subgroups has not been established to illustrate their three-dimensional (3-D) architectures in the human colon. In this research, we integrate c-kit immunostaining, 3-D microscopy with optical clearing, and image rendering to present the location-dependent network orientations with high definition. Full-depth colonic tissues were obtained from colectomies performed for nonobstructing carcinoma. Specimens of colon wall were prepared away from the tumor site. C-kit and nuclear fluorescent staining were used to identify the ICC processes and cell body. Optical clearing was used to generate transparent colon specimens, which led to panoramic visualization of the fluorescence-labeled ICC networks at the myenteric plexus (ICC-MY), longitudinal (ICC-LM) and circular (ICC-CM) muscles, and submucosal boundary (ICC-SM) up to 300 µm in depth via confocal microscopy with subcellular level resolution. We observed four distinct network patterns: 1) periganglionic ICC-MY that connect with ICC-LM and ICC-CM, 2) plexuses of ICC-LM within the longitudinal muscle and extending toward the serosa, 3) repetitive and organized ICC-CM layers running parallel to the circular muscle axis and extending toward the submucosa, and 4) a condensed ICC-SM layer lining the submucosal border. Among the four patterns, the orderly aligned ICC-CM layers provide an appropriate target for quantitation. Our results demonstrate the location-dependent network orientations of ICC subgroups and suggest a practical approach for in-depth imaging and quantitative analysis of ICC in the human colon specimen.

Chronic effect of vagotomy in the morphometry of the myenteric plexus of rats' duodenum / Efeito crônico da vagotomia sobre a morfometria do plexo mioentérico do duodeno de ratos

BACKGROUND: The gastrointestinal disorders have been associated with morphological alterations in the myenteric nervous plexus. AIM: To evaluate, through morphometric studies, the chronic effects of the subdiaphragmatic trunk vagotomy on the nervous plexus. METHODS: Fifteen male exemplars of Wistar Rattus novergicus weighing about 150g, distributed into three groups, have been used: control (n=5), Sham (n=5) and vagotomized (n=5). The animals were sacrificed after 30 and 90 days post surgery. Fragments of duodenum were fixed in Bouin solution, embedded into paraffin and stained with HE and PAS. Morphometric analysis was performed by a Carl Zeiss KM 450 image system. The following aspects were observed: the density of nervous cells per linear micrometer (µm) (ND); the area of perikarya (µm²) (NA); the number of satellite cells per µm (SCD); and the number of satellite cells per neuron (SC/N). The averages were compared with the help of "software" program Sigma Plus through two way - ANOVA and Tuckey post-test. RESULTS: Denervation increased SC/N (p<0,05) and NA (p<0,05), in a time-dependent denervation way (p<0,05). However ND and SCD, decreased, which significantly with the animal's age (p<0,001). CONCLUSION: Vagotomy altered the myenteric plexus morphology in a time-dependent way.

RACIONAL: As disfunções gastrintestinais têm sido associadas à alterações morfológicas no plexo nervoso mioentérico. OBJETIVO: Avaliar através do estudo morfométrico, os efeitos crônicos da vagotomia troncular subdiafragmática sobre esse plexo nervoso. MÉTODOS: Foram utilizados 15 exemplares machos de Rattus novergicus da variedade Wistar, com cerca de 150 g, distribuídos nos grupos controle (n=5), Sham (n=5) e vagotomizados (n=5). Os animais foram sacrificados depois de 30 e 90 dias após as operações. Em seguida, fragmentos do duodeno foram fixados em solução de Bouin, incluídos em parafina e corados por HE e PAS. A análise morfométrica foi realizada por meio do sistema de análise de imagem Carl Zeiss KM 450. Foram observados: a densidade de células nervosas por micrômetro linear (µm); a área dos pericários (µm²); o número de células satélites por µm; e o número de células satélites por neurônio. As médias foram comparadas com o auxílio do programa de "software" Sigma Plus através do Two way - ANOVA e do pós-teste de Tukey. RESULTADOS: A desnervação aumentou o número de células satélites por neurônios (p<0,05) e a área média dos pericários (p<0,05), de maneira dependente do tempo de desnervação (p<0,05), mas diminuiu significativamente a densidade de neurônios (p<0,05) e de células satélites (p<0,05) em função da idade (p<0,001). CONCLUSÃO: A vagotomia alterou a morfologia do plexo mioentérico de maneira dependente do tempo.

Spatial pattern analysis of nitrergic neurons in the myenteric plexus of the duodenum of different mammalian species.

Nitrergic myenteric neurons are especially susceptible to the development of neuropathy in functional gastrointestinal disorders. Investigations of the similarities and dissimilarities in the organization of nitrergic neurons in the various mammalian species are therefore important in an effort to determine the extent to which the results obtained in different animal models can be generalized. In the present work, the density and the spatial organization of the nitrergic neurons in the myenteric plexus of the duodenum were investigated in 7 mammalian species. After nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) histochemistry, the Plexus Pattern Analysis software (PPAs) was applied to count the nuclei of nitrergic neurons, calculate the proportions of the areas covered by the plexus and perform randomization analysis. All 7 species exhibited a large population of nitrergic myenteric neurons, with densities in the range 12-56 cells/mm 2 . The distribution patterns of these neurons differed markedly in the different species, however, the rat was the only species in which the nitrergic neurons appeared to be randomly distributed. The PPAs in conjunction with NADPH-d histochemistry proved to be a simple and fast tool with which to reveal similarities and dissimilarities in the spatial arrangement of the nitrergic neurons in the different species.

Atrophy of the nitrergic myenteric neurons in the descending colon rats submitted to protein and vitamin deficiency / Atrofia en neuronas mientéricas nitrérgicas en el colon descendente de ratas sometidas a deficiencia de proteínas y vitaminas

Effects of protein and B-complex vitamin deficiency were assessed with respect to the morphometry of myenteric neurons in the descending colon of adult rats. Sixteen animals were divided into two groups: Control Group (CG, n=8) and Experimental Group (EG, n=8). The CG received 22 percent protein chow and the EG received 4 percent protein chow for 120 days. The descending colon was submitted to NADH- and NADPH-diaphorase technique in order to evidence nervous cells in the whole mounts preparations. In the EG, NADH-d positive neurons presented reduced nuclei, while NADPH-d positive neurons showed atrophy of the soma area (~41.7 percent) inducing an increase of the proportion occupied by the nucleus inside in the soma of these cells.

Esta investigación buscó evaluar los efectos de la desnutrición proteica y vitamínica delcomplexo B sobre aspectos morfométricos del plexo mientérico del colon descendente de ratones adultos. Dieciséis animales fueron distribuidos en dos grupos: control que recibieron ración comercial con 22 por ciento de proteína y experimental alimentados con ración de tenor proteico reducido para 8 por ciento, durante 120 días. Neuronas del plexo mientérico presentes en preparados totales fueron evidenciados a través de la técnica histoquímica de la NADH-diaforasa y de la NADPH-diaforasa. En el grupo experimental, las neuronas NADH-d positivos sufrieron reducción del núcleo celular, ya las neuronas NADPH-d sufrieron atrofia de 41,7 por ciento de la superficie de su pericarion, lo que hizo con que el núcleo celular pasase a ocupar una mayor proporción de la región trófica de las neuronas.

Alterações morfométricas no plexo mioentérico do cólon menor equino distendido experimentalmente / Morphometrical alterations in myoenteric plexus of experimentally distended equine small colon

O cólon menor dos equinos é frequentemente acometido por afecções obstrutivas, sendo a disfunção da motilidade uma complicação comum após o tratamento cirúrgico. Este transtorno pode estar relacionado com lesões no plexo mioentérico ocorridas durante a distensão intestinal, contudo pouco se sabe sobre sua fisiopatologia. O objetivo deste estudo foi avaliar as alterações morfológicas na inervação mioentérica em segmentos de cólon menor de eqüinos submetidos à distensão intraluminal com pressão suficiente para promover redução da perfusão microvascular (isquemia parcial) da parede intestinal. Nove eqüinos foram submetidos à distensão do cólon menor por 4h. Fragmentos da parede intestinal foram colhidos antes e ao final da distensão, após 1,5 e 12 horas de reperfusão no segmento experimental e ao final do procedimento em segmento distante. As amostras foram fixadas e processadas rotineiramente e secções histológicas foram coradas com cresil violeta para a morfometria. Por meio de um software de análise de imagens, obtiveram-se a área, o perímetro e os diâmetros mínimo e máximo do corpo neuronal, do núcleo e do nucléolo dos neurônios e as áreas do citoplasma e do nucleoplasma. Verificou-se redução significativa (P<0,05) das áreas do corpo neuronal e do citoplasma ao final da distensão, retornando aos valores equivalentes aos iniciais durante a reperfusão. Conclui-se que a distensão intraluminal alterou morfologicamente os neurônios do plexo mioentérico. Essas modificações morfológicas podem estar associadas e contribuir para explicar a disfunção da motilidade freqüentemente observada em casos clínicos.

The equine small colon is frequently affected by obstruction, and intestinal motility dysfunction is a common complication after its surgical treatment. This fact may be related to myoenteric plexus lesion caused by distention; however, little is known about the pathophysiology of this condition. The objective of this study was to evaluate the morphological alterations in the myoenteric inervation of segments of small colon of horses subjected to intraluminal distension with reduction of the microvascular perfusion (partial ischemia) of the intestinal wall. Nine horses were used to promote distension of on segment of small colon for 4 hours. Samples of intestinal wall were collected before and at the end of the distension, after 1.5 and 12 hours of reperfusion in the experimental segment and at the end of the procedure in a different distant segment. Samples were processed and histological sections were stained with cresyl violet for the morphometric studies. An image analyzer software was used to measure perimeter, diameter, and area of the neuronal body, nucleus and nucleolus of the neurons and the areas of the cytoplasm and nucleoplasm. Significant reductions (P<0.05) in the areas of the neuronal body and cytoplasm were detected at the end of intestinal distension, returning to the basal values during the reperfusion. In conclusion, intraluminal distension promoted changes in the morphology of the neurons of myoenteric plexus. These morphological modifications may be associated to the motility dysfunction frequently observed in clinical cases.

Fall in density, but not number of myenteric neurons and circular muscle nerve fibres in guinea-pig colon with ageing.

In guinea-pig ileum, ageing has been associated with a decrease in enteric neurons. This study examined guinea-pig colon and measured changes in gut dimensions, neuron size, density and ganglionic area. Changes in motor nerve fibres in the circular muscle were also measured. Myenteric neurons in whole-mount preparations of mid-colon from 2-week, 6-month, and 2-year-old guinea-pigs were labelled immunohistochemically with the neuronal marker human neuronal protein HuC/HuD, and numbers of neurons mm(-2), neuronal size, ganglionic area mm(-2), gut length, circumference and muscle thickness were measured. Corrected numbers of neurons mm(-2) and ganglionic area mm(-2) accounting for growth of the colon were calculated. Additionally, nerve fibres in circular muscle cross-sections were labelled with antibodies against nitric oxide synthase (NOS) and substance P (SP) and the density of nerve fibres in circular muscle was measured. The numbers of neurons mm(-2) decreased by 56% (from 2 weeks to 2 years) with no change in neuron size. Total neuron numbers decreased by 19% (P = 0.14) when adjusted for changes in length and circumference with age. The percentage area of NOS- and SP-immunoreactive (IR) nerve fibres in the circular muscle decreased (P < 0.001), but the total area of NOS and SP-IR nerve fibres increased (P < 0.01) due to an age-related increase in muscle thickness. The density of myenteric neurons in guinea-pig mid-colon halved from 2 weeks to 2 years, but when the increase in colon dimensions was considered, the number of neurons decreased by only 19%. The percentage area of motor nerve fibres in the circular muscle decreased with no change in total volume of nerve fibres.

Density and morphometry of overall myenteric neurons population from the duodenum of diabetic rats (Rattus norvegicus) under ascorbic acid supplementation / Densidad y morfometría de la población total de neuronas mientéricas del duodeno de ratones diabéticos (Rattus norvegicus) tratados con ácido ascórbico

The objective of this work was to evaluate the overall myenteric neurons population from the duodenum of adult streptozotocin-induced diabetic rats supplemented with ascorbic acid (AA), a potent antioxidant. Fifteen 90-day-old rats were divided in groups: control (C), diabetic (D), diabetic treated with ascorbic acid (DA). After 120 days of experimental period duodenums were resected and processed as whole-mount preparations according to Giemsa's technique, which allowed us to evaluate neuronal density in an area of 8.96 mm² and measure the area of 500 neuronal cell bodies per group. It was observed a 32.55% reduction in neuronal density of group D when compared to group C (p<0.05). The density of spared neurons in group DA, in relation to group D, was not statistically different in this experimental model. No significant differences were found in neuronal areas when groups C and D or group D and DA were compared (p>0.05). These results lead us to conclude that the density of overall myenteric neurons population from the duodenum was reduced in diabetic rats (D), when compared to its control (C); and that diabetic rats supplemented with AA (DA) did not have their neuronal density preserved when compared to diabetic animals (D).

El objetivo de este trabajo fue evaluar la población total de neuronas mientéricas del duodeno de ratones adultos inducidos a diabetes por estreptozotocina, suplementados con ácido ascórbico (AA), un poderoso antioxidante. Quince ratones con 90 días de edad fueron divididos en los grupos: control (C), diabético (D) y diabético tratados con ácido ascórbico (DA). Después de 120 días de tratamiento con AA, los duodenos fueron resecados y procesados con el método de Giemsa, el cual permitió evaluar la densidad neuronal, en un área de 8,96 mm², y medir el área del soma de 500 neuronas por grupo. Se observó una reducción de 32,55% de la densidad neuronal del grupo D con respecto grupo C (p<0,05). La densidad de las neuronas observada en el grupo DA, en relación con el grupo D, no fue estadísticamente significativa en este modelo experimental. No fueron encontradas diferencias significativas en las áreas de neuronas, cuando los grupos C y D o el grupo D y DA (p>0,05) fueron comparados. Nuestros resultados permitieron concluir que la densidad de la población total de las neuronas mioentéricas del duodeno estuvo reducida en los ratones diabéticos comparados con los controles, mientras que, los ratones diabéticos suplementados con AA no mantuvieron su densidad neuronal cuando fueron comparados con los animales del grupo diabético.