Calpain inhibitor A-558693 in experimental focal cerebral ischemia in rats.
OBJECTIVE
Calpains are intracellular proteases, which are activated in various cerebral injuries. We studied the expression of mu-calpain in a model of focal cerebral ischemia/reperfusion and the efficacy of the calpain inhibitor A-558693.


METHODS
A transient occlusion of the middle cerebral artery was produced in male Wistar rats by using the suture model with 3 hours of ischemia and 24 hours of reperfusion. Six animals were given the calpain inhibitor and six animals were treated with placebo. The infarct size was determined by the loss of the calpain substrate microtubule-associated protein-2 (MAP-2) immunohistochemistry using volumetry in serial slices of the brains. Furthermore mu-calpain positive-stained cells were detected by immunohistochemistry and western blotting.


RESULTS
In placebo-treated animals the mu-calpain expression was significantly increased in the ischemic hemisphere compared with the contralateral non-ischemic hemisphere (88.6 versus 10.5% in the basal ganglia, 60.7 versus 10.7% in the cortex, p < 0.001, respectively) with a subsequent loss its substrate MAP-2. However, the use of the calpain inhibitor A-558693 did not significantly change the mu-calpain expression, nor significantly reduce the infarct volume.


CONCLUSIONS
The present data indicate that mu-calpain proteolysis plays an important role in the chain of events following cerebral ischemia. However, the calpain inhibitor A-558693 failed to prevent these changes.
Department of Neurology, Klinikum Grosshadern, Ludwig-Maximilians-University, Munich, Germany.
Martin
M
Liebetrau
Helge
H
Martens
Nora
N
Thomassen
Dorothe
D
Burggraf
Dusica
D
Gabrijelcic-Geiger
Wolfgang
W
Lubisch
Achim
A
Möller
Gerhard F
GF
Hamann
D000577:Amides / Q000627:therapeutic use; D000818:Animals; D015153:Blotting, Western / Q000379:methods; D020520:Brain Infarction / Q000473:pathology / Q000517:prevention & control*; D002545:Brain Ischemia / Q000188:drug therapy* / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D002154:Calpain / Q000037:antagonists & inhibitors* / Q000378:metabolism; D002452:Cell Count / Q000379:methods; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*; D005786:Gene Expression Regulation / Q000187:drug effects; D007150:Immunohistochemistry / Q000379:methods; D020244:Infarction, Middle Cerebral Artery / Q000150:complications; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D015427:Reperfusion Injury / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control
C503763:A-558693; D000577:Amides; D004791:Enzyme Inhibitors; D002154:Calpain; C449002:mu-calpain