Administration of female rats with 5,5-dithiobis-(2-nitrobenzoic acid) or [thioredoxin] small interfering RNA to the caudate nucleus decreased the protective effect of E(2) against FC-induced injury. [...] Increase of brain [thioredoxin] activity might play an important role in the E(2)-mediated neuroprotective effect against FC-induced brain injury in female rats.