Introduction: Chronic stress is the main environmental factor in the aetiology of depression and
it is known that this type of stress may cause alterations in brain regions such as the
hippocampus. Nevertheless, changes in a cellular basis are still a subject of study. Objective: The
analysis of microglial cells and immature neurons in the dentate gyrus (DG) of stressed mice.
Methods: C57BL/6J mice were subjected to Social Defeat Stress model (SDS), consisting of 6
days of social isolation prior to 10 days of stressor. The DG was analysed using
immunohistochemistry techniques against Iba1 (microglia) and DCX (immature neurons)
following image analysis (ImageJ) to obtain morphological and distribution data of microglial
somas. Furthermore, hippocampal neurogenesis was assessed through stereological
quantification of DCX+ cells (Visiopharm). Results: An increase in soma size under chronic stress
conditions was shown, as well as a less circular and more ameboid soma. These changes were
observed mainly in the infrapyramidal blade of the DG. According to microglial cells distribution
parameters, the granular cell layer (GCL) was the region which presented the highest microglial
density under SDS. Regarding hippocampal neurogenesis, a decrease in the number of DCX+
Type 2-3 cells was observed in the whole DG. Conclusion: All these results o!er a more profound
insight of stress changes at a cellular level and could contribute to a better understanding of
neurobiological basis in pathologies such as depression. Projects: PSI2017-83408-P (MINECO)
and P20 00460 (Consejería de Conocimiento, Investigación y Universidades, Junta de Andalucía).University of Málaga and the projects PID2020-117464RB-I00 (Ministerio de Ciencia e
Innovación, Spain) to Pedraza C. and Pérez-Martin M., PSI2017-83408-P (FEDER/Ministerio de
Ciencia, Innovación y Universidades, Spain) to Pedraza C., UMA20- FEDERJA-112 (FEDER/Junta
de Andalucía) to Pedraza C. and Pérez-Martin M. and P20-00460 (Consejería de Conocimiento,
Investigación y Universidades, Junta de Andalucía) to Pedraza C. Predoctoral Fellowship:
FPU16/05308 to Nieto-Quero A. and FPU19/03629 to Infantes-López MI., Ayuda A.2 para
Contrato Predoctoral Del I Plan Propio de Investigación, Transferencia y Divulgación Científica
de la Universidad de Málaga, Convocatoria 2021 to Munoz-Martin J.
Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec
