title: Neutral red staining for the assessment of acute outcome in rat focal cerebral ischemia models.
abstract: Neutral red staining was evaluated as an acute outcome assessment method in rat models of cerebral ischemia by comparison with histological infarction volume. Fischer 344 rats (n = 48) were used in three different models of middle cerebral artery (MCA) occlusion: proximal MCA occlusion (n = 16), distal MCA occlusion followed by ipsilateral common carotid artery (CCA) occlusion (distal MCA/CCA occlusion, n = 15), and MCA occlusion with an intravascularly introduced 4-0 nylon suture (intravascular MCA occlusion, n = 17). At 1 hour, 2 hours, and 4 hours after MCA occlusion, animals were injected with 2.5 ml of 4% neutral red solution via the femoral vein, and then sacrificed. Proximal MCA occlusion caused a neutral red defect volume in the cortex which correlated well with histological infarction volume at 4 hours (r = 0.88, p < 0.05), and in the caudate which correlated well with infarction volume at 4 hours (r = 0.94, p < 0.01). Distal MCA/CCA occlusion caused a neutral red defect volume in the cortex lager than the histological infarction volume (4 hrs: 88.6 +/- 11.8 vs. 74.3 +/- 17.4 mm3, p < 0.05) but closely correlated with the infarction volume at 4 hours (r = 0.81, p < 0.05). Intravascular MCA occlusion caused a neutral red defect volume in only two of 17 animals after 1-4 hours, which correlated well with the absence of histological evidence of infarction. Neutral red staining is a simple method for assessing the acute outcome of focal cerebral ischemia as early as 4 hours after the onset, in an appropriate model of cerebral ischemia.
authors.affiliation: Department of Neurological Surgery, Tokushima University.
authors.forename: M
authors.initials: M
authors.lastname: Uno
authors.forename: K
authors.initials: K
authors.lastname: Matsumoto
authors.forename: M C
authors.initials: MC
authors.lastname: Wallace
mesh_terms: D000818:Animals; D001157:Arterial Occlusive Diseases / Q000150:complications / Q000503:physiopathology; D002545:Brain Ischemia / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D002339:Carotid Arteries / Q000503:physiopathology; D002536:Cerebral Arteries / Q000503:physiopathology; D008297:Male; D009499:Neutral Red; D051381:Rats; D013997:Time Factors
chemical_list: D009499:Neutral Red