Antegrade cerebral perfusion during deep hypothermia circulatory arrest attenuates the apoptosis of neurons in porcine hippocampus.
BACKGROUND
Cerebral damage is a major problem after reconstructive surgery of the aortic arch and the descending aorta. Current protective strategies, including deep hypothermia and antegrade cerebral perfusion (ACP), are used to prolong the tolerated duration of circulatory arrest. The aim of the study was to observe the influence of deep hypothermic circulatory arrest (DHCA) and ACP on neuronal apoptosis in the hippocampus. To further elucidate the mechanisms of neurologic injury and protection, we assessed the expression of the antiapoptotic protein Bcl-2 and the proapoptotic protein Bax.


METHODS
We randomly divided 18 pigs into 3 groups: The control group (n = 6) received normal-temperature cardiopulmonary bypass (CPB), the DHCA group (core temperature, 18 degrees C; n = 6) received DHCA for 90 minutes, and the third group (DHCA + ACP) (core temperature, 18 degrees C; ACP, flow rate of 30 mL/kg per minute at a pressure of 15-25 mm Hg; n = 6) received DHCA for 90 minutes. Hippocampal tissue was sampled 2 hours after CPB was finished. Bcl-2 and Bax expression was examined by immunohistochemistry. Morphologic changes in hippocampal tissue were measured with transmission electron microscopy.


RESULTS
Bax protein levels were significantly higher in the DHCA group than in the other 2 groups (P < .05), whereas Bcl-2 protein levels were significantly higher in the DHCA + ACP group than in the other 2 groups (P < .05). Obvious neuronal apoptosis was observed in the DHCA group but not in the controls, and few apoptotic neurons were seen in the DHCA + ACP group.


CONCLUSIONS
DHCA can induce neuronal apoptosis in the hippocampus. ACP during the DHCA period protects cerebral tissue by suppressing apoptosis through decreasing Bax expression and increasing Bcl-2 expression.
Zhao
Rong
R
Department of Cardiovascular Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
Cui
Qin
Q
Yu
Shi-Qiang
SQ
Sun
Guo-Cheng
GC
Wang
Hong-Bing
HB
Jin
Zheng-Xiao
ZX
Gu
Chun-Hu
CH
Yi
Ding-Hua
DH
D000818:Animals; D017209:Apoptosis; D001930:Brain Injuries / Q000378:metabolism*; D050792:Circulatory Arrest, Deep Hypothermia Induced / Q000379:methods*; D006624:Hippocampus / Q000378:metabolism*; D008297:Male; D009474:Neurons / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D015424:Reperfusion / Q000379:methods*; D013552:Swine
D019253:Proto-Oncogene Proteins c-bcl-2