Spatial resolution of calpain-catalyzed proteolysis in focal cerebral ischemia.

Abstract

Transient forebrain ischemia induces calpain-mediated degradation of the neuronal cytoskeleton, alpha-fodrin, and this results in ischemic neuronal death. In this study, we investigated the spatial distribution and temporal changes of calpain-catalyzed alpha-fodrin proteolysis in focal cerebral ischemia and examined the effects of a calpain inhibitor. Ischemia was induced in gerbils by 3-h middle cerebral artery occlusion followed by reperfusion. Animals were divided into four groups: a sham-operated group, an ischemic group, a vehicle-treated group, and a calpain inhibitor-treated group. Intravenous injections of vehicle or calpain inhibitor I were administered 30 min before ischemia. Infarct volumes were measured 1 day after reperfusion and the spatial distribution of calpain-catalyzed alpha-fodrin proteolysis was investigated by immunohistochemistry 15 min, 1 h, 4 h, and 1 day after reperfusion. Infarct volume (mean +/- SD) in the ischemic group and the vehicle-treated group was 204.6 +/- 19.1 mm3 and 212.4 +/- 16.3 mm3, respectively, and the calpain inhibitor I reduced the infarct volume [149.4 +/- 25.2 mm3 (P < 0.05)]. Immunoblot analysis demonstrated that calpain inhibitor reduced proteolysis. Ischemia induced fodrin proteolysis in the ischemic core and the peri-infarct zone within 15 min after reperfusion, with proteolysis developing quickly in the ischemic core and more slowly in the peri-infarct zone. Proteolysis preceded neuronal death in the peri-infarct zone. Calpain inhibitor I ameliorated neuronal death in the peri-infarct zone but not in the ischemic core. Thus, calpain plays a pivotal role on focal ischemia as well as in global ischemia.

• Authors: Atsushi Kambe, Masayuki Yokota, Takaomi C Saido, Ichiro Satokata, Hirokazu Fujikawa, Sadaharu Tabuchi, Hideki Kamitani, Takashi Watanabe
• Journal: Brain research (Brain Res) Vol. 1040 Issue 1-2 Pg. 36-43 (Apr 08 2005) ISSN: 0006-8993 [Print] Netherlands
• PMID: 15804424 (Publication Type: Comparative Study, Journal Article)

Chemical References

• Glycoproteins
• calpain inhibitors
• Peptide Hydrolases
• Calpain

Topics

• Animals
• Brain (drug effects, enzymology)
• Brain Ischemia (enzymology, prevention & control)
• Calpain (analysis, antagonists & inhibitors, metabolism)
• Catalysis (drug effects)
• Female
• Gerbillinae
• Glycoproteins (pharmacology, therapeutic use)
• Peptide Hydrolases (analysis, metabolism)