We have found that cultured differentiated astrocytes pretreated with N⁶, 2^'-O-dibutyryladenosine 3',5'-cyclic monophosphate (DBcAMP), a permeable analogue of cAMP, incorporate thymidine, but not uridine, via nucleoside transporters into TCA insoluble fraction for repair on DNA injury in the presence of hydrogen peroxide (H₂O₂) at an early time, and these phenomena are specific in differentiated astrocytes, but not undifferentiated astrocytes and neurons.
We studied expression of nucleoside transporter ENT3 in cultured astrocytes by immunocytochemistry. Astrocyte is stained by anti-GFAP antibody and anti-ENT3 antibody, followed by treated by Texas Red and FITC-conjugated secondary antibody. We could confirm ENT3, that is assumed to be presented in lysosome, in cultured astrocytes co-stained by GFAP.
These results indicate that ENT3 could relate with H₂O₂-induced thymidine incorporation and DNA repair in cultured astrocytes.