Microglia-derived glial cell line-derived neurotrophic factor could protect Sprague-Dawley rat astrocyte from in vitro ischemia-induced damage.

The interrelationship between microglia and astrocytes in cerebral ischemia was determined in vitro by adding in vitro ischemia-induced supernatant from microglia into astrocytes under the same conditions (glucose-, oxygen- and serum-free). The involvement of glial cell line-derived neurotrophic factor (GDNF) was further investigated by immunoblocking assay and Western blot analysis. Results showed that microglia-derived supernatant protected against in vitro ischemia-induced damage of astrocytes and this protection was pre-blocked by anti-GDNF but not normal rabbit serum. In addition, in vitro ischemia appeared to induce the expression of GDNF in microglia. These results indicate that microglia-derived protection on astrocytes during in vitro ischemia is GDNF-dependent.