Up-regulation of neuronal and astrocytic GLT-1 mRNA in the hippocampal CA1 subfield during the induction of brain ischemic tolerance in rats.
Our previous study showed that 3-min cerebral ischemic preconditioning (CIP) up-regulated the expression of glial glutamate transporter-1 (GLT-1) protein, which protects pyramidal neurons, allowing them to survive an 8-min ischemic insult that usually induces severe delayed neuronal death in the hippocampal CA1 subfield. In the present study, in situ hybridization and immunohistochemistry were used to observe whether GLT-1 mRNA is modulated and whether actrocytes and/or neurons express GLT-1 mRNA during the induction of brain ischemic tolerance. We observed that GLT-1 mRNA is expressed in neurons and astrocytes in the hippocampal CA1 subfield. The expression of GLT-1 mRNA was significantly down-regulated in both neurons and astrocytes after the 8-min lethal ischemic insult. CIP for 3 min increased the expression of GLT-1 mRNA in neurons and astrocytes, and induced the elongation of the astrocytic processes around pyramidal neurons. It may be concluded that CIP performed 2 days before lethal ischemic insult activated astrocytes, which resulted in an increased number of lengthened processes expressing high levels of GLT-1, which protected the neurons and allowed them to survive 8-min ischemic insult that is usually lethal to neurons in the hippocampal CA1 subfield.
Min
M
Cao
Hebei Medical University,Shijiazhuang, PR China. Email: hebmuzhangmin@163.com.
Min
M
Zhang
Lian-Wei
LW
Zhang
Jian-Xue
JX
Gong
Cui-Juan
CJ
Liang
Wen-Bin
WB
Li
D000704:Analysis of Variance; D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D002545:Brain Ischemia / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control; D056547:CA1 Region, Hippocampal / Q000473:pathology*; D002452:Cell Count; D004195:Disease Models, Animal; D027342:Excitatory Amino Acid Transporter 2 / Q000235:genetics* / Q000378:metabolism; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D019194:Ischemic Preconditioning; D008297:Male; D009474:Neurons / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D015854:Up-Regulation / Q000502:physiology*
D027342:Excitatory Amino Acid Transporter 2; D005904:Glial Fibrillary Acidic Protein; D012333:RNA, Messenger; C493395:Slc1a2 protein, rat