Immunohistochemical evaluation of the postnatal effects of acute exposure to ethanol on the kinetics of granule-cecll migration in rat cerebellum

Exposure of the developing central nervous system (CNS) to ethanol leads to impaired cellular migration. In the cerebellar cortex, cell proliferation occurs in the early postnatal period. Granular cells generated in the external granular layer (EGL) migrate to their final destination at the internal granular layer. In this work, we examined the ethanol-induced alterations in cerebellar granular cells during their formation in 12-day postnatal (P12) Wistar rats (Rattus norvegicus). Three intraperitoneal (i.p.) injections of 20 por cento ethanol (3 g/kg of body weight) were administered to each rat at 5 h intervals folowed by 5’-bromo-2- deoxyuridine (BrdU, 60 mg/kg, i.p.) 16 h after the last injection. The rats were sacrificed 2 h or 24 h after the administration of BrdU and the brain was removed and embedded in paraffin. BrdU was subsequently detected immunohistochemically in sections of brain tissue. There was a decrease in the number of external granular cells and in the number of cell layers in the cerebellar EGL in all of the groups that received ethanol when compared to their respective controls. There was also a decrease in these parameters in the 2 h and 24 h survival period after BrdU administration. These results indicate that exposure to ethanol during granule cell generation and neuronal migration in the cerebellum is harmful, and that a study of the quantitative alterations in EGL neurons of the developing rat cerebellum exposed to ethanol in the postnatal period can provide a better understanding of ethanol-induced or related disturbances in the CNS.

Effects of acute prenatal exposure to ethanol on the postnatal morphology of the prefrontal cortex in wistar rats

Prenatal exposure to ethanol is frequently associated with micronecephaly, hypomyelinization, delayed cell migration, and impaired neuronal and glial maturation in the offspring. The mechanism by which ethanol induces its effects on the development of the nervous system is still not fully understood. In this study, the influence of acute prenatal exposure to ethanol on the prefrontal cortex cells of rats were examined. Three doses of ethanol (3g/kg of body weight) were administered intraperitoneally to pregnant female rats on the 12th day of pregnacy, at 8 hours intervals. Control rats received the same treatment but with a saline solution. Cells in the synthesis phase (S) of the cell cycle were labeled with bromodeoxyuridine. Six controls and 12 ethanol-treated neonates were sacrificed on the 8th day of postnatal life. The distance between nuclear cores in immunohistochemically labeled cells was determined by image analysis. Control rats had a normal neocortex, with six layers in the prefrontal region. Rats treated with ethanol showed ectopia of pyramidal neurons in layers I and II, heterotopia in the basal area of the prefrontal fissure, and a decrease in cellular density in layers I and VI of the cerebral prefrontal cortex. These alterations could help to explain some of the dysfunctions reported in patients with fetal alcohol syndrome.

Morphometric analysis of myelinated axons during maturation in the fasciculus gracilis and fasciculus cuneatus of rats. A transmission electron microscopy study

The process of myelination is an important event in the maturation of the nervous system. In this study, the fasciculus gracilis and fasciculus cuneatus in the first and sixth cervical segments of the spinal cord a mutant strain of Wistar rats, were studied by electron microscopy in order to determine the perimeter of the axons, the thickness of the myelin sheath, and the diameter and perimeter of the nerve fibers. At birth, the fasciculus gracilis and fasciculus cuneatus had unmyelinated fibers, but by the fifth day after birth myelination was in progress. The mean perimeter of nerve fiber was significantly greater (p<0.05) in the fasciculus cuneatus compared to the fasciculus gracilis at 15, 20 and 120 days of age. The diameter of the fibers, perimeter of the axons and thickness of the myelin sheath were more developed in the fasciculus cuneatus than in the fasciculus gracilis at all ages studied. The axons were relatively thinner 15-20 days after birth than at 20-120 days after birth. The myelination of the fasciculi gracilis and cuneatus in the spinal cord of this mutant strain, agreed with previous reports indicating that the mutation, which causes the rats to have bare skin, had no significant effect on myelination in the anatomical areas studied.

Reparaçäo tecidual da mucosa lingual de ratos submetidos a açäo do raio laser CO2: estudo experimental empregando a microscopia eletrônica de varredura / Tissue repairment of the tongue mucosa in rats submitted to CO2 Laser: experimental study using scanning electron microscopy

Foram descritos os efeitos do raio laser CO2 sobre a mucosa dorsal da língua de ratos durante a reparaçäo tecidual, empregando-se a técnica de microscopia eletrônica de varredura. Os resultados mostraram que: 1) a mucosa lingual apresenta um processo intenso de reparaçäo tecidual, muito embora a área da ferida cirúrgica permaneça delimitada nos períodos analisados; 2) houve a neoformaçäo epitelial espessa e a formaçäo de estruturas circulares semelhantes às papilas filiformes

Estudo ao microscópio eletrônico de varredura da mucosa dorsal da língua de fetos humanos / Scanning electron microscopy study of the lingual dorsal mucosae of the human fetuses

No presente trabalho foram estudadas as características da mucosa dorsal da língua de fetos humanos natimortos com 12, 16, 18 e 22 semanas, empregando a técnica da microscopia eletrônica de varredura. A mucosa lingual de fetos de 12 semanas apresenta formaçöes globosas, que se diferenciam posteriormente em papilas fungiformes e formaçöes correspondentes às papilas valadas no terço posterior. Na décima sexta semana, evidenciam as papilas fungiformes, as valadas com aspecto mais diferenciados e as filiformes. Na margem lateral posterior da língua mostram-se sulcos e pregas de mucosa dispostos transversamente. Na décima oitava semana, as papilas fungiformes apresentam uma superfície ligeiramente convexa, e as valadas bem desenvolvidas e contendo poros gustativos. Os sulcos e pregas de mucosa da margem lingual mostram-se evidentes, constituindo as papilas folhadas. Na vigésima segunda semana, as papilas fungiformes säo bem maiores que nas fases anteriores e as filiformes säo numerosas. Notam-se as papilas valadas com formas definidas, bem como as folhadas bem evidentes na margem lateral da língua

Estudo das alteraçöes ultra-estruturais da mucosa lingual de ratos incisada com raio laser de CO2 / A study of the ultrastructural features of the rat langue mucosa incised by CO2 laser

Os autores observaram as características ultra-estruturais da mucosa lingual resultantes da incisäo com raio laser de CO2. Notaram que houve a formaçäo de um sulco profundo e as paredes apresentaram microprojeçöes de material carbonizado necrótico

Observaçöes morfológicas das papilas linguais do tatu peba (Euphractus sexcinctus): estudo aos microscópios óptico e eletrônico de varredura / Morphological observations of the tongue papillae of the armadillo (Euphractus sexcinctus): light and scanning electron microscope study

Foram estudadas as características da mucosa lingual do tatu peba, Euphractus sexcinctus, utilizando-se microscópios óptico e eletrônico de varredura. No dorso da língua observa-se grande quantidade de papilas filiformes, exceto na área mais posterior. As papilas fungiformes estäo distribuídas entre as filiformes. No terço posterior notam-se duas papilas valadas de forma elíptica. A regiäo póstero-lateral apresentou uma fenda oblíqua com algumas papilas folhadas que contêm os botöes gustativos. Na superficie das papilas fungiformes e valadas, nota-se a presença de poros gustativos e de numerosas micropregas na superfície celular. A face da língua possui papilas cônicas simples