[Changes of approximate entropy in rats during focal cerebral infarction].
OBJECTIVE
To investigate the changes of EEG approximate entropy (ApEn) in rats during focal cerebral infarction.


METHODS
Twenty-four Sprague-Dawley (SD) rats were randomly divided into infarction group (n=12) with middle cerebral artery occlusion and sham-operated group (n=12). The EEG data (ApEn) was recorded in the bilateral areas (C3, C4) of the rats with focal cerebral infarction before the infarction and immediately and at 5, 15, 30, and 60 min after the infarction. The same measurement was carried out in the sham-operated group.


RESULTS
In the sham-operated group, ApEn in C3 and C4 showed no obvious differences at the time points (P>0.05), but in the infarction group, ApEn in C3 and C4 increased significantly after the infarction. ApEn in the ischemic area (C4) was significantly lower than that in the non-ischemic area (C3) (P<0.05). The bilateral ApEn decreased with the passage of time. ApEn in the ischemic area (C4) was significantly lowered at 30 min after the infarction in comparison with that before infarction (P<0.05). In the sham-operated group, ApEn showed no significant difference between C3 and C4. ApEn was comparable between the two groups before the operation.


CONCLUSIONS
ApEn can help monitor the occurrence of focal cerebral infarction of rats, and may be used to assess the extent of cerebral ischemia after infarction.
Ouyang
Ming-Wen
MW
Department of Anesthesiology, Nanfang Hospital, Southern University, Guangzhou 510515, China. ouyangmm2008@yahoo.com.cn
Lin
Chun-Shui
CS
Qin
Zai-Sheng
ZS
Gu
Miao-Ning
MN
D000818:Animals; D002544:Cerebral Infarction / Q000503:physiopathology*; D004569:Electroencephalography; D019277:Entropy; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley