Dexamethasone enhances NT-3 expression in rat hippocampus after traumatic brain injury.
The cellular events in traumatic brain injury (TBI) are complicated, and the factors mediating neurotrophins to protect and repair the injured brain cells are only beginning to be identified. This study examined the effect of dexamethasone (DEX) on neurotrophin-3 (NT-3) expression following TBI. Levels of NT-3 mRNA and protein in rat hippocampus were measured using in situ hybridization and immunohistochemistry, respectively. After TBI, the NT-3 mRNA expression was down-regulated during the first 24 h. DEX reversed the post-traumatic reduction of NT-3 mRNA expression at 2, 4, 6, and 12 h in the hippocampus, and also decreased the cell death in hippocampal hilum and supraventricular cerebral cortex after 7 days. The NT-3 protein levels generally corresponded to the mRNA levels in the hippocampal region. DEX enhanced the NT-3 expression after TBI, indicating that post-traumatic neuroprotection in the hippocampus is at least partially mediated by NT-3 and thus can be modulated by DEX treatment.
Yang
Jen-Tsung
JT
Departments of Neurosurgery, Chang Gung Memorial Hospital, Chia-Yi, Taiwan.
Lee
Tsong-Hai
TH
Weng
Hsu-Huei
HH
Chang
Chen-Nen
CN
Chen
Wen-Cheng
WC
Cheng
Wan-Chun
WC
Wu
June Hsieh
JH
D000704:Analysis of Variance; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects; D001930:Brain Injuries / Q000188:drug therapy / Q000378:metabolism*; D002452:Cell Count / Q000379:methods; D003907:Dexamethasone / Q000494:pharmacology* / Q000627:therapeutic use; D004195:Disease Models, Animal; D005786:Gene Expression Regulation / Q000187:drug effects; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism; D007150:Immunohistochemistry / Q000379:methods; D017403:In Situ Hybridization / Q000379:methods; D008297:Male; D020933:Neurotrophin 3 / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013194:Staining and Labeling / Q000379:methods; D013997:Time Factors
D000893:Anti-Inflammatory Agents; D020933:Neurotrophin 3; D012333:RNA, Messenger; D003907:Dexamethasone