We previously demonstrated that a synthetic
retinoic acid receptor agonist,
Am80, attenuated
intracerebral hemorrhage (ICH)-induced neuropathological changes and neurological dysfunction. Because inflammatory events are among the prominent features of ICH pathology that are affected by
Am80, this study investigated the potential involvement of proinflammatory
cytokines/
chemokines in the effect of
Am80 on ICH. ICH induced by
collagenase injection into mouse striatum caused prominent upregulation of mRNAs for
interleukin (IL)-1β,
tumor necrosis factor (TNF)-α,
IL-6, CXCL1, CXCL2, and CCL3. We found that
dexamethasone (DEX) and
Am80 differently modulated the increase in expression of these
cytokines/
chemokines; TNF-α expression was attenuated only by DEX, whereas CXCL2 expression was attenuated only by
Am80. Expression of IL-1β and
IL-6 was inhibited both by DEX and
Am80. Neurological assessments revealed that
Am80, but not DEX, significantly alleviated motor dysfunction of mice after ICH. From these results, we suspected that CXCL2 might be critically involved in determining the extent of motor dysfunction. Indeed, magnetic resonance imaging-based classification of ICH in individual mice revealed that invasion of
hematoma into the internal capsule, which has been shown to cause severe neurological disabilities, was associated with higher levels of CXCL2 expression than ICH without internal capsule invasion. Moreover, a CXCR1/2 antagonist
reparixin ameliorated neurological deficits after ICH. Overall, suppression of CXCL2 expression may contribute to the beneficial effect of
Am80 as a therapeutic agent for ICH, and interruption of CXCL2 signaling may provide a promising target for ICH
therapy.