The influence of body temperature on infarct volume and thrombolytic therapy in a rat embolic stroke model.
The effect of body temperature on cerebral infarcts and thrombolytic therapy was investigated in 91 rats embolized in the right carotid territory. Hypothermia of 32 degrees C for 2 h with preembolic onset (n = 15) or hyperthermia of 39 degrees C for 2 h with postembolic onset (n = 22) was compared to normothermic controls (n = 17). After 48 h of survival, neuropathological evaluation with measurement of infarct volume was performed. Median infarct volume in percent of affected hemisphere volume was 11% (9-21, quartiles) in rats treated with hypothermia alone, compared to 46% (14-59, quartiles) in normothermic controls (P = 0.04). Hyperthermia for 2 h increased median infarct volume to 65% (37-75, quartiles). There was a positive and significant correlation between infarct volume and body temperature (R = 0.53, P = 0.0002, n = 54). Mortality rate was significantly higher among rats treated with hyperthermia compared to normothermic controls (P = 0.005). A subset of 37 rats exposed to the same temperature regimen were treated with tissue plasminogen activator (20 mg/kg i.v. during 45 min) 2 h after embolization. Judged by posttreatment carotid angiography, hyperthermic rats (n = 11) had the best degree of recanalization (P = 0.03) compared to controls (n = 17), but median infarct volume in this group was (58% (27-67, quartiles)) significantly larger (P < 0.02) than normothermic (21% (15-39, quartiles), n = 14) and hypothermic (13% (7-31, quartiles), n = 12) rats treated with thrombolytic therapy. Thrombolytic therapy following 2 h of hypothermia, could not improve the effect of hypothermia alone.(ABSTRACT TRUNCATED AT 250 WORDS)
Meden
P
P
Neurovascular Research Laboratory, Rigshospitalet, Copenhagen, Denmark.
Overgaard
K
K
Pedersen
H
H
Boysen
G
G
D000818:Animals; D001831:Body Temperature; D002533:Cerebral Angiography; D002544:Cerebral Infarction / Q000473:pathology* / Q000503:physiopathology / Q000628:therapy*; D002561:Cerebrovascular Disorders / Q000209:etiology*; D006979:Hyperthermia, Induced; D007036:Hypothermia, Induced; D002542:Intracranial Embolism and Thrombosis / Q000150:complications*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins; D016019:Survival Analysis; D015912:Thrombolytic Therapy; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use
D011994:Recombinant Proteins; D010959:Tissue Plasminogen Activator