Pervious experimental studies have shown that XQ-1h has beneficial
neuroprotective effect in the
cerebral ischemia reperfusion injury. However, the therapeutic time window for treatment of focal
cerebral ischemia reperfusion injury with XQ-1h is not clear. Under
chloral hydrate anesthesia, transient focal
cerebral ischemia was induced in rats by 2h of
middle cerebral artery occlusion (MCAO), followed by 24h of reperfusion. Saline as vehicle or XQ-1h at the doses of 31.2, 15.6 and 7.8 mg/kg i.v. was administered at 0.5, 1, 2, 3h after induction of
ischemia. Subsequently, 24h after MCAO
brain edema,
infarct volume, neurological deficits and cerebral blood flow were evaluated. Administrations of XQ-1h at the doses of 31.2mg/kg at 0.5, 1, and 2h after reperfusion of MCAO significantly reduced
infarct rate (%) by 75.6% (5.2 ± 1.7), 66.2% (7.2 ± 1.9), and 47.9% (11.1 ± 1.2), respectively. XQ-1h (31.2mg/kg) treatment, 0.5, 1, and 2h after reperfusion produced significant improvement in neurological score compared to vehicle-treated group (P<0.01). Administrations of XQ-1h at the doses of 31.2mg/kg and 15.6 mg/kg at 0.5, 1, and 2h after reperfusion of MCAO significantly increased cerebral blood flow (mv) by 16.9 ± 1.9, 11.7 ± 1.3, 9.5 ± 1.0, respectively (P<0.01). In conclusion the therapeutic time window of XQ-1h for
cerebral ischemia reperfusion injury is within 2h. Interestingly, we also discovered that the therapeutic time window of XQ-1h is deeply related with the activity of scavenging oxidative stress products. Further studies need to be conducted more
drug combination therapy programs in order to assess the potential clinical application of XQ-1h.