HMOX2 and hemorrhage: Conversely, the articles dealing with the neuroprotective effects of HO-2 were performed in adult HO-2 null mice, exposed to middle-cerebral artery occlusion (1 h occlusion followed by 23 h reperfusion) or collagenase injection, to mimic ischemia or hemorrhage, respectively, and whose brains were removed and analyzed just after the end of the experiments without any further in vitro manipulation.