Abstract: Objective　To investigate whether the poly-ADP ribose polymerase-1 (PARP-1) inhibitor PJ34, N- (6-oxo-5,6-dihydrophenanthridin-2-yl)-2-dimethylamino can improve the integrity of the blood-brain barrier after rt-PA administration in rats with cerebral ischemia reperfusion.　Methods　Totally 60 rats were randomly divided into a sham operation group, an IR group, a rt-PA group and a PJ34 group. IR group: focal cerebral ischemia 2 h reperfusion model was made by modifying Zea Longa method. PJ34 group and rt-PA group: the fish line was removed 2 h after ischemia, rt-PA (10 mg/kg) was administered to the tail vein, and PJ34 or physiological saline (3 mg/kg) was intraperitoneally injected. The neurological function score was evaluated, the permeability of the blood-brain barrier was measured by Evans blue staining, and the expressions of MMP-9, Claudin-5 and ZO-1 was analyzed by immunohistochemistry.　Results　The mNSS score, Evans blue content and MMP-9 expression in rt-PA group were significantly higher than those in the IR group, and those in PJ34 group were lower than those in rt-PA group, but were  higher than those in IR group (P＜0.05). The expression of Claudin-5 and ZO-1 in rt-PA group was lower than that in IR group, higher in PJ34 group than in rt-PA group, but lower than that in IR group (P<0.05).    Conclusions    PJ34 can effectively improve the integrity of blood-brain barrier of rt-PA rats after cerebral ischemia by inhibiting the expression of MMP-9 and increasing the expressions of Claudin-5 and ZO-1.

Key words:  , PJ34, 　Blood-brain barrier, 　Ischemia reperfusion, 　rt-PA