Spatial resolution of calpain-catalyzed proteolysis in focal cerebral ischemia

• Published in: Brain research Vol. 1040; no. 1; pp. 36 - 43
• Main Authors: Kambe, Atsushi, Yokota, Masayuki, Saido, Takaomi C., Satokata, Ichiro, Fujikawa, Hirokazu, Tabuchi, Sadaharu, Kamitani, Hideki, Watanabe, Takashi
• Format: Journal Article
• Language: English
• Published: London Elsevier B.V 08-04-2005; Amsterdam Elsevier; New York, NY
• Subjects: Animals; Biological and medical sciences; Brain - drug effects; Brain - enzymology; Brain Ischemia - enzymology; Brain Ischemia - prevention & control; Calpain; Calpain - analysis; Calpain - antagonists & inhibitors; Calpain - metabolism; Catalysis - drug effects; Female; Focal cerebral ischemia; Gerbillinae; Glycoproteins - pharmacology; Glycoproteins - therapeutic use; Medical sciences; Middle cerebral artery; Neurology; Peptide Hydrolases - analysis; Peptide Hydrolases - metabolism; Vascular diseases and vascular malformations of the nervous system; α-fodrin; α-fodrin; Focal cerebral ischemia; Disorders of the nervous system; Calpain; Middle cerebral artery; α-fodfin; Enzyme; Cysteine endopeptidases; Rodentia; Central nervous system; Cardiovascular disease; Encephalon; Peptidases; Vertebrata; Experimental disease; Mammalia; Ischemia; Proteolysis; Animal; Hydrolases; Gerbil
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/j.brainres.2005.01.080

Transient forebrain ischemia induces calpain-mediated degradation of the neuronal cytoskeleton, α-fodrin, and this results in ischemic neuronal death. In this study, we investigated the spatial distribution and temporal changes of calpain-catalyzed α-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 α-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 mm
3 and 212.4 ± 16.3 mm
3, respectively, and the calpain inhibitor I reduced the infarct volume [149.4 ± 25.2 mm
3 (
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.