Reduction but not cleavage of poly(ADP-ribose) polymerase during stress-mediated cell death in the rat hippocampus.
Sustained stress induces neuronal atrophy and death, especially in the hippocampus, which impairs hippocampal function. However, underlying mechanisms of stress-induced neuronal damage have not been precisely defined. We analyzed the molecular events related to apoptosis in the hippocampus of rats exposed to immobilization stress. Terminal dUTP nick end-labeling exhibited positive nuclei in the hippocampus of stressed rats, indicating DNA fragmentation. RT-PCR and Western blot analyses showed that immobilization stress increased and decreased the expression of pro-apoptotic gene bax and anti-apoptotic bcl-2 genes, respectively. Western blot analysis demonstrated that the characteristic 85 kDa apoptotic fragment of poly(ADP-ribose) polymerase (PARP) was not observed in the hippocampus subjected to immobilization stress. The amount of PARP protein was significantly reduced following stress. This study may provide a novel insight into molecular mechanisms implicated in hippocampal damage associated with stress.
Yun
Su-Jin
SJ
Graduate School of East-West Medical Science, Kyung Hee University, Yong-In, Korea.
Lee
Doo-Jae
DJ
Kim
Mi-Ok
MO
Jung
Bomi
B
Kim
Sung Ok
SO
Sohn
Nak Won
NW
Lee
Eunjoo H
EH
D000818:Animals; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D006624:Hippocampus / Q000201:enzymology* / Q000473:pathology*; D006868:Hydrolysis; D008297:Male; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013312:Stress, Physiological / Q000201:enzymology* / Q000473:pathology*
D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011065:Poly(ADP-ribose) Polymerases