Vol. 33, N║ 3

Cytoarchitecture and brain-derived neurotrophic factor immunolocalisation in the cerebellar cortex of African grasscutter (Thryonomys Swinderianus)

Ibe, C. S.; Ojo, S. A.; Salami, S. O.; Ayo, J. O.; Nlebedum, U. C.; Ikpegbu, E.

KEYWORDS: Purkinje layer, external germinal layer, granular layer, African grasscutter, brain-derived neurotrophic factor.

ABSTRACT: Introduction: The study described the lamina organization and immunolocalisation of brain-derived neurotrophic factor in the cerebellar cortex of the African grasscutter, at defined postnatal periods. Materials and Method:áBrain samples extracted from African grasscutter neonates on postnatal day 3, juveniles on postnatal day 72 and adults on postnatal day 450 were prepared for routine histology and immunohistochemistry, using antibody specific to brain-derived neurotrophic factor. Results: On postnatal day 3, all the laminae typical of the concentric lamina organisation of the mammalian cerebellar cortex were evident, but, and external germinal layer was also observed. On postnatal day 72, and thereafter, the external germinal layer was no more evident. On postnatal day 3, the tree-like arrangement (Arbor vitae) of the cerebellum was not very striking, as the interlobular fissures were incomplete. On postnatal day 72, the Arbor vitae were better presented, as more lobules had been completely separated by interlobular fissures; although, there were some incompletely separated lobules, presented with interlobular fissural lines. On postnatal day 450, the lobules were distinct as the interlobular fissures separated all the vermal and hemispheric lobules. In all the postnatal periods, the granule cell layer was the most populated, while the Purkinje layer was a single cell line of Purkinje neurones. At all postnatal periods, strong immunoreactivity to brain-derived neurotrophic factor was observed in the Purkinje layer; the cell bodies and dendrites of all Purkinje neurones were immunoreactive; while the nuclei in neonate Purkinje neurons where not immunoreactive, the nuclei in the adults were immunoreactive. The cerebellar granule cells were not brain-derived neurotrophic factor immunoreactive, suggestive of their non-synthesis or loss of the synthesized protein, by anterograde axonal transport, to paracrine function. Conclusion: These findings and others were related to some behaviours of the African grasscutter, and compared with similar report in other rodents.