Histological changes during development of the cerebellum in the chick embryo exposed to a static magnetic field

Abstract

Few studies have been performed to evaluate the ultrastructural changes that exposure to static magnetic fields (SMF) can cause to the processes of cell migration and differentiation in the cerebellum during development. Thus, we have studied the development of the cerebellum in the chick embryo (n = 144) under a uniform SMF (20 mT). All of our observations were done on folium VIc of Larsell's classification. The cerebella of chick embryos, which were exposed solely on day 6 of incubation and sacrificed at day 13 of incubation [short exposure (S)1; n = 24], showed an external granular layer (EGL) that was less dense than the EGL in the control group (n = 24). The molecular layer (ML) exhibited a low number of migratory neuroblastic elements. Moreover, the internal granular layer (IGL) was immature, with the cellular elements less abundant and more dispersed than in controls. In chick embryos exposed on day 6 of incubation and sacrificed at day 17 (S2; n = 24), the outstanding feature was the regeneration of the different layers of the cerebellar cortex. The cerebellar cortex of chick embryos exposed continuously to an identical field from the beginning of the incubation up to day 13 [long exposure (L)1; n = 24] or day 17 (L2; n = 24) of incubation showed a higher number of alterations than that of group S1. Electron microscopy confirmed the findings from light microscopy and, at the same time, showed clear signs of cell degeneration and delay in the process of neuronal differentiation. This was more apparent in groups L1 (100%) and L2 (100%) than in groups S1 (95.4%) and S2 (65.2%). In conclusion, the present study showed that SMF can induce irreversible developmental effects on the processes of cell migration and differentiation of the chick cerebellar cortex. Bioelectromagnetics 18:36–46, 1997. © 1997 Wiley‐Liss, Inc.

Transient vimentin expression during the embryonic development of the chicken cerebellum

“…1D), although EGL thickness was reduced at the embryonic days E17 (HH 43; 6 cell layers at the base and 4 at the apex) and E19 (3 cell layers). At day E17, Purkinje cells formed a single row between the molecular and the granular layers, in agreement with previous studies (Feirabend, 1990; Espinar et al, 1997). In general, at parasagittal levels, fissures were less deep than in mid‐sagittal ones (data not shown).…”

Histomorphogenesis of The Cerebellum of The Grey Breasted Helmeted Guinea Fowl (<i>Numida meleagris galeata</i>) Pre and Post Hatch. I

“…The molecular and granular layers in this study were prominent but the single row of immature Purkinje cells, non-distinctive nucleoli and traces of the EGL were only eminent on day 26 of incubation. This varies with the observation of Espinar et al (1997) in chicken in which the Purkinje cells formed a single row on day 17 of incubation.…”

The developing role of fetal magnetic resonance imaging in the diagnosis of congenital cardiac anomalies: A systematic review

“…[41] Other studies have noted decreased survival fraction for mouse embryos in the two-cell stage after being exposed to a 1.5 T static field for 30 minutes,[42] delay and reduction of hatching Heliothis veriscens eggs,[43] irreversible damage in the cerebellar cortex of chicks exposed to 20 mT magnetics fields as embryos. [44] A human study focusing on pregnant MRI workers found no significant differences among pregnancy parameters in women who were exposed to MRI magnetic fields. [45] Duration of exposure is noted to be associated with more of the adverse effects noted in other animal models.…”