Abstract 211: Delayed Cell Death in CA1 Region in a Cardiac Arrest Rat Model: Continuing After 2 Weeks of Survival?
Background: Evolution of histological lesions in selectively vulnerable brain regions in animal models of cardiac arrest (CA)give evidence of potential therapeutic windows. Delayed cell death is of special interest in this regard.
Methods: In male Sprague-Dawley rats (350g) ventricular fibrillation (VF) CA was induced for 6 min followed by chest compressions, ventilation and drugs for 2 min. To achieve return of spontaneous circulation animals were defibrillated every 2 min. Animals were sacrificed after one week (n=5) or two weeks (n=7) of survival and compared to four sham animals. Brains were fixed in formalin, embedded in paraffin wax and cut into 3 μm thick coronary sections for histological examination. Viable neurons with nucleolus were counted in Hematoxylin-Eosin (HE)-stained sections in a 250 μm sector of the medial CA1 region. FluoroJade B staining was applied to count dying neurons in the same sector.
Results: In HE-staining sham animals had 31±4 viable neurons. In one week survivors 11±9 viable neurons (p=0.003) and in two week survivors 7±7 viable neurons (p=0.001 vs sham, p=0.49 vs one week survivors) were counted. Furthermore, a lot of degenerated hypereosinophilic neurons were present in HE-staining in both CA-groups. FluoroJade B-staining was negative in sham animals. In one week survivors 29±8 dying neurons (p=0.006) and in two week survivors 33±13 dying neurons (p= 0.016 vs sham, p=0.343 vs one week survivors) were detectable.
Conclusions: Consistent damage in the medial CA1 region was present after 6 min VFCA in both survival time groups. Lesions seemed to be constant, with no significant differences between time points. Contrary to expectations, FluoroJade B-staining was still positive after two weeks of survival, suggesting that delayed cell death might go on for a longer time period than assumed so far.
Author Disclosures: S. Högler: None. U. Teubenbacher: None. W. Weihs: None. F. Sterz: None. I.M. Magnet: None. F. Ettl: None. A. Warenits: None. A. Schober: None. C. Testori: None. M. Holzer: None. D. Grassman: None. M. Wagner: None. P. Kodajova: None. A. Janata: Research Grant; Modest; Austrian Science Foundation P24824.
- © 2014 by American Heart Association, Inc.