Figure 1.

Experimental procedure. After stabilization for 1 h, animals were subjected to ventricular fibrillation. They were either sacrificed with a potassium chloride injection (KCl) after 0, 5, 20 or 30 min after untreated cardiac arrest (A) or, after 12 min of cardiac arrest and 8 min of cardiopulmonary resuscitation (CPR), return of spontaneous circulation (ROSC) was carried out and animals received a saline solution (Rosc groups) or methylene blue (MB groups) before sacrifice at 30, 60 and 180 min post-resuscitation (B).