Proliferative response of distinct hippocampal progenitor cell populations after cortical infarcts in the adult brain.

Precursor cells in the adult dentate gyrus are a heterogeneous population. Astrocytic cell types with radial glia-like morphology and low proliferative activity have been distinguished from highly dividing subtypes expressing early neuronal properties. Recent evidence indicates that physiological stimuli predominantly increased proliferation of non-astrocytic cell types whereas radial glia-like precursors remained quiescent. We here analyzed the proliferative response of precursor cell subtypes under pathophysiological conditions in a model of photochemical cortical infarcts. Using transgenic pNestin-GFP mice and single intraperitoneal injections of 5-bromo-2-deoxyuridine 4 h after surgery, immunocytochemical analysis revealed a differential activation of the distinct subpopulations within 72 h after the infarct. The stimulation was most prominent in radial glia-like precursor cells but also non-astrocytic precursors with early neuronal phenotypes were activated. The present study indicates that the proliferative response of precursor cell subpopulations in the subgranular zone might differ under physiological and pathophysiological conditions.