Estrogen treatment
increased white matter sparing, decreased apoptosis in both the young and middle-aged
rats. Endogenous estrogen in young group also showed neuroprotection but this effect
was not seen in middle-aged rats. Furthermore, estrogen induced the upregulation of
Hsp27 and ER in young rats. Estrogen-treated rats showed improvement of locomotor
recovery in both ages and this improvement correlated with white matter sparing. These
data demonstrated that estrogen treatment protects against SCI and strongly suggest
that older animals remain responsive to the protective actions of 17β-estradiol.