021 | Early response of immune myeloid cells after olfactory nerve damage

Cellular and Molecular Neurobiology

Author: Javier Hernán Fotti | Email: jfotti@fmed.uba.ar

Javier Hernán Fotti , Germán La Iacona , Juan Emilio Belforte , Lorena Rela

1° Universidad de Buenos Aires. Facultad de Medicina. Departamento de Fisiología y Biofísica. Buenos Aires, Argentina. CONICET-Universidad de Buenos Aires. Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO). Buenos Aires, Argentina

The olfactory nerve regenerates efficiently. After damage to sensory neurons, increased proliferation of stem cells is observed in the olfactory epithelium, which restores the neuronal population in about two months. Besides neuronal axons, the olfactory nerve is populated by immune myeloid cells, which proliferate and get reactive after damage to the nerve, and olfactory ensheathing cells, which are recognized for their neurotrophic properties. We propose that the mechanisms involved in the reparative capacity of the olfactory nerve involve an early response of immune cells that interact with olfactory ensheathing cells. In this study, we began to evaluate the morphological changes of immune myeloid cells at early stages of the nerve repair process after damage, following administration of an olfatototoxin (methimazole). Preliminary results after Sholl analysis of cells immunostained for Iba1 (Ionized calcium-binding adaptor molecule 1) in the olfactory bulb of methimazole-treated mice show reduced cell complexity in this group, particularly on days 2 and 3 post-injury, which is compatible with a reactive microglia phenotype early after damage. Together with measures of cell reactivity markers and a pharmacological approach to selectively eliminate immune myeloid cells, these experiments will contribute to determining whether these cells trigger responses in olfactory ensheathing cells and/or modulate the repair process.