MMP11 expression in human and rat brain following stroke. RT-PCR demonstrated an increase in MMP11 mRNA levels in infarcted and peri-infarcted areas of patients surviving from 2 to 6 days following stroke (Ai) and rats at 3 days after MCAO (Aii). Western blotting demonstrated an increase in protein levels in infarcted and peri-infarcted areas of patients surviving for 29 (Bi) and 26 (Bii) days following stroke. Weak MMP11 staining in cells from contralateral areas of a patient surviving for 5 days following stroke (Ci). Blood vessels (Cii) and neurons (Ciii) strongly stained for MMP11 in peri-infarcted areas of a patient surviving for 15 days after stroke (arrows). No MMP11 staining observed in contralateral hemisphere of rat brain at 1 h after MCAO (Di) but neurons from infarcted areas of rat brain were stained positive for MMP11 at 3 days following MCAO (Dii) (C: Contralateral, P: Peri-infarct, I: Infarct).