Contralateral response of macrophages and astrocytes to injury in the cerebral hemisphere of 6‐day‐old rat following prenatal gamma irradiation

Abstract

Wistar pregnant rats were exposed to a single 1.0 Gy dose of gamma rays on gestational days 13, 15, 17 or 19 (E13, E15, E17 and E19, respectively). When offsprings of the irradiated females became 6-day-old, they received a mechanical injury of the cerebral hemisphere. One or 2 days after the injury, [3H]thymidine was injected and the animals were perfused. Brain sections were processed for BSI-B4 isolectin histochemistry or immunohistochemistry for glial fibrillary acidic protein (GFAP) or S-100-beta protein and subjected to autoradiography to visualise proliferating and non-proliferating macrophages or proliferating astrocytes. Significant changes in the contralateral response to injury related to the day of prenatal irradiation could be detected. The response was minimal following irradiations performed on E15 and E17. At those stages of prenatal development, the majority of cortical neurons with interhemispheric connections were formed. Therefore, irradiation-induced reduction of the neurons might minimise transfer of pathogenic stimuli to contralateral areas via degenerating nerve fibers. Consequently, the degree at which the contralateral glial response reflected reactive changes at the lesion site might also be minimal. Results of the present study do not show in detail mechanisms underlying the differences in the contralateral reactivity to injury. They, however, might be of importance to histopathological investigations using animal models of cerebral dysplasia.

Unilateral optic nerve crush induces bilateral retinal glial cell proliferation

“…The present study demonstrated that glial cell proliferation was bilaterally enhanced due to unilateral crush of the ON in a laminaspecific manner and this bilateral response is in accordance with previous studies on bilateral cellular changes that occur after unilateral injury of the ON (Bodeutsch et al, 1999;Setkowicz et al, 2004). Specifically, BrdU-positive cells were shown to express GFAP, characterizing astroglia (NFL ⁄ GCL) or Muller cells (INL), and OX-42, characterizing microglia (all layers).…”

“…The present study demonstrated that glial cell proliferation was bilaterally enhanced due to unilateral crush of the ON in a lamina‐specific manner and this bilateral response is in accordance with previous studies on bilateral cellular changes that occur after unilateral injury of the ON (Bodeutsch et al. , 1999; Setkowicz et al. , 2004).…”

Implementation of X-ray fluorescence microscopy for investigation of elemental abnormalities in central nervous system tissue

“…Afterwards, one set of samples was directly cut with a cryotome and another was embedded in paraffin and then cut with a microtome. The paraffin samples were prepared according to the standard procedures described elsewhere [11]. All the rat brain samples were cut into 15 m thick sections and mounted on the ultralene foil.…”

Geração de espécies reativas de oxigênio e neuroinflamação induzidas por enucleação ocular no sistema visual de ratos.

“…Além disso, de acordo com dados da literatura, tanto a retina quanto o nervo óptico contralaterais ao olho lesionado são freqüentemente utilizados como controles em estudos in vivo e in vitro (BODEUTSCH et al, 1999). Contudo, de acordo com alguns autores, a utilização do hemisfério cerebral ipsolateral à enucleação ocular como controle, bem como a utilização da retina e do nervo óptico contralaterais ao olho lesionado como controles, deve ser cuidadosamente reconsiderada por diversas razões (BODEUTSCH et al, 1999;SETKOWICZ et al, 2004;PANAGIS et al, 2005). Existem indícios, por exemplo, da existência de pequenas projeções recíprocas entre as retinas (projeção retino-retinal) (MULLER e HOLLANDER, 1988), as quais poderiam justificar a proliferação bilateral de células da glia na retina após a secção unilateral do nervo óptico (PANAGIS et al, 2005).…”