Temporal Characteristics of Cytosolic Translocation of Mitochondrial Proteins in Permanent Distal Middle Cerebral Artery Occlusion Model of Rats.

Shin, Byoung Wook; Sung, Jae Hoon; Hong, Jae Taek; Son, Byung Chul; Lee, Sang Won; Park, Chun Kun

Original Article

Journal of Korean Neurosurgical Society 2007;41(5): 306-313.

Byoung Wook Shin, Jae Hoon Sung, Jae Taek Hong, Byung Chul Son, Sang Won Lee, Chun Kun Park

Department of Neurosurgery, St. Vincent's Hospital, The Catholic University of Korea, Suwon, Korea. jaehoonsung@gmail.com

ABSTRACT

OBJECTIVE
In permanent distal middle cerebral artery occlusion (pdMCAO) model of rats, the temporal order of subcellular translocation is not fully understood yet. We studied translocation sequence of cytochrome c and apoptosis inducing factor (AIF) after pdMCAO and patterns of expression.
METHODS
Twenty-one male rats - with ten minutes, 1, 4, 8, 24 and 48 hours of pdMCAO groups - were enrolled. At core and penumbra area of each cerebral cortex, Western blotting of cytochrome c and AIF were performed using cytosolic fractions and then compared with sham specimens. With 48 hours group, the expression of cytochrome c and AIF was examined with immunofluorescent staining.
RESULTS
Compared to sham, the cytosolic translocation of cytochrome c significantly increased at all time points (p<0.05). As early as 10 min after onset of ischemia, it was increased significantly (p<0.01). The cytosolic translocation of AIF showed gradual increase with the passage of time and significantly increased 8 hours after (p<0.05). As late as 24 hours and 48 hours after onset of ischemia, there were increased most significantly (p<0.01). At penumbra, both proteins failed to show significant increase at all time points. At 48 hours after ischemia, colocalization of cytochrome c and AIF were confirmed.
CONCLUSION
Cytosolic translocation of cytochrome c peaks much earlier than that of AIF in pdMCAO model of rat. Caspase dependent apoptosis activates soon after ischemia and later, it can be reinforced by gradually increasing AIF in ischemic core.

Key Words: Apoptosis; Mitochondrial proteins; Cytochrome c; Apoptosis inducing factor; Middle cerebral artery occlusion; Ischemia