Learning induces rapid morphologic plasticity in mouse hippocampal astrocytes

JAVIER H FOTTI; AGOSTINA M STAHL; VALERIA DELLA MAGGIORE; ANA PAULA SIEBEN SAMEK; GERMÁN LA IACONA; PAOLA YANIRA MATTEI PEÑA; JUAN BELFORTE; LORENA RELA

Buenos Aires

Congreso; FIRST MEETING GLIA CLUB SOUTHERN CONE; 2022

Club de la glía

Astrocytes are key mediators of diverse forms of synapticplasticity. In addition to the release of soluble factors, astrocytesbecome hypertrophic and in closer interaction withsynapses when animals are exposed to challenging contexts,such as learning paradigms. Many studies have shown howastrocytic structural remodeling takes place in learning paradigms,however, little is known about the time course ofastrocyte remodeling in short-lasting learning contexts. Inthis study, we asked whether astrocytic morphological alterationstake place shortly after a motor learning task. To thisaim, two different groups of mice were trained in a rotarodtask set to an accelerated (learning group) or constant (activecontrol group) speed. In both cases, the brains of these micewere processed for morphological analysis of astrocytes attwo-time points (30 min or 24 h post-training). After immunostaining of brain sections for astrocytic markers(GFAP and S100B), we examined hippocampal astrocytemorphology in all groups. Our data show an increasedGFAP staining intensity in the hippocampus of the learninggroup at 24 h post-training, compared to controls (28±3vs. 20±3 AU, t-test, p=.0492). When exploring astrocyteprocess complexity through Sholl analysis, we observed atendency to greater complexity in the learning group, comparedto the active control. Unexpectedly, we also discovereda tendency for an astrocytic soma volume reductionin the 24 h learning group when compared to the 24 h activecontrol group. Taken together, these results indicate thatastrocytic remodeling takes place shortly after learning andsupports the idea that astrocytic remodeling contributes toneural plasticity processes involved in learning.