Expression and changes of endogenous insulin-like growth factor-1 in neurons and glia in the gerbil hippocampus and dentate gyrus after ischemic insult.
In the present study, we focused upon expression and changes of endogenous insulin-like growth factor-1 (IGF-1) in the hippocampus of the Mongolian gerbil after ischemic insult. In sham-operated animals, IGF-1 immunoreactivity was absent from the hippocampus. IGF-1-immunoreactive (IR) neurons were detected at 12 h and 1 day after ischemic insult. In the hippocampal CA1 area, the IGF-IR neurons were non-pyramidal cells (GABAergic neurons). In the hippocampal CA2/3 areas, the IGF-1-IR neurons were pyramidal and non-pyramidal cells, and in the dentate gyrus the IGF-1-IR neurons were hilar neurons. Four days after ischemia-reperfusion, IGF-1 immunoreactivity disappeared from neurons, and significantly increased in astrocytes and microglia. These results suggest that the induction of IGF-1 in the CA1 area during the early stage (12-24 h after ischemic insult) is associated with the relative vulnerabilities of pyramidal glutamatergic neurons and non-pyramidal GABAergic neurons. The later increase (4 days after ischemic insult) of IGF-1 expression and protein content was found to promote the activities of astrocytes and microglia. These increases of IGF-1 in astrocytes and in microglia are associated with mechanisms that compensate for the effects of delayed neuronal death.
Hwang
In Koo
IK
Department of Anatomy, College of Medicine, Hallym University, Chuncheon 200-702, South Korea.
Yoo
Ki-Yeon
KY
Park
Seung-Kook
SK
An
Sung-Jin
SJ
Lee
Jae-Yong
JY
Choi
Soo Young
SY
Kang
Jung Hoon
JH
Kwon
Young-Guen
YG
Kang
Tae-Cheon
TC
Won
Moo Ho
MH
D000818:Animals; D002545:Brain Ischemia / Q000378:metabolism*; D018891:Dentate Gyrus / Q000737:chemistry / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology; D005849:Gerbillinae; D006624:Hippocampus / Q000737:chemistry / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000096:biosynthesis*; D008297:Male; D009457:Neuroglia / Q000737:chemistry / Q000378:metabolism*; D009474:Neurons / Q000737:chemistry / Q000378:metabolism*
D007334:Insulin-Like Growth Factor I