Brain damage following severe acute normovolemic hemodilution in combination with controlled hypotension in rats.
OBJECTIVE
The reduced oxygen content and perfusion pressure during acute normovolemic hemodilution (ANH) and controlled hypotension (CH) raise concerns about hypoperfusion and ischemic injury to the brain. In this study on rats, we examined the brain damage following four different degrees of ANH combined with CH.


METHODS
Forty rats were randomly assigned to receive a sham operation or CH and ANH [with a hematocrit (Hct) of 30, 25, 20 or 15%]. ANH was performed after baseline physiological parameters had been monitored for 20 min; 30 min later, CH was induced using sodium nitroprusside, and the mean arterial blood pressure was maintained at 50-60 mmHg for 1 h. Rats were killed 3.5 h after hemodilution. Ultrastructural alterations in the CA1 region of the rat hippocampus were observed, and serum concentrations of S100B and neuron-specific enolase (NSE) were measured before and after ANH.


RESULTS
The serum S100B concentration increased significantly in the Hct 20% + CH and Hct 15% + CH groups. However, there were no significant differences in the serum levels of NSE between the groups. In the CA1 region of the rat hippocampus, marked ultrastructural alterations, such as mitochondrial denaturalization and nucleus distortion, were observed in the Hct 20% + CH and Hct 15% + CH groups.


CONCLUSIONS
Severe ANH (Hct < or = 20%) combined with CH may induce cerebral damage, as confirmed by marked ultrastructural alterations in the CA1 region of the rat hippocampus and significantly increased serum levels of S100B, and should be avoided.
Ge
Y L
YL
Department of Anesthesiology, Subei People's Hospital, Xuzhou Medical College, Xuzhou, China.
Lv
R
R
Zhou
W
W
Ma
X X
XX
Zhong
T D
TD
Duan
M L
ML
D000208:Acute Disease; D000818:Animals; D001158:Arteries / Q000378:metabolism; D001930:Brain Injuries / Q000378:metabolism / Q000473:pathology*; D005740:Gases / Q000378:metabolism; D006438:Hemodilution; D006624:Hippocampus / Q000648:ultrastructure; D007023:Hypotension, Controlled; D008297:Male; D008854:Microscopy, Electron; D009414:Nerve Growth Factors / Q000097:blood; D010751:Phosphopyruvate Hydratase / Q000097:blood; D051381:Rats; D017207:Rats, Sprague-Dawley; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000097:blood
D005740:Gases; D009414:Nerve Growth Factors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; C579158:S100b protein, rat; D010751:Phosphopyruvate Hydratase