The experimental study of hypoxia-inducible factor-1alpha and its target genes in spinal cord injury.
METHODS
Animal model of compressive spinal cord injury (SCI), reverse transcription-polymerase chain reaction (RT-PCR), in situ hybridization (ISH), immunohistochemistry (IHC) and enzymehistochemistry (EHC) were used to test the hypothesis that hypoxia-inducible factor-1alpha (HIF-1alpha) and the target genes activated by HIF-1alpha are involved in cell hypoxia tolerance and tissue vascularity to help injured tissue to go through the stress disease.


OBJECTIVE
To determine whether HIF-1alpha and its target genes associated with hypoxia tolerance and neovascularization take part in the pathophysiological procedure of SCI in rats.


METHODS
Yunnan University, China.


METHODS
Random-bred adult male Sprague-Dawley (SD) rats weighing 250+/-50 g were prepared for compressive SCI models. After receiving compressive injury at T(10), rats were sacrificed at different times from 6 h to 1 week after injury. The injured cords were removed, and HIF-1alpha and its target genes were assayed by RT-PCR, ISH, IHC and EHC. The data were statistically analyzed.


RESULTS
An increase in HIF-1alpha mRNA expression was observed 12 h postinjury, reached a maximum at 3 days, and reduced gradually thereafter. HIF-1alpha protein expressed earlier than HIF-1alpha mRNA. Additionally, two glycolytic enzymes and vascular endothelial growth factor (VEGF), which are regulated by HIF-1alpha, also increased after an interval postinjury, and their expression patterns shared a same trend with that of HIF-1alpha protein.


CONCLUSIONS
The findings suggested that the most important hypoxic regulatory factor HIF-1alpha was upregulated in involved cells by activating the transcription and increasing protein stability, and subsequently activated the expression of HIF-1alpha target genes, including glycolytic enzymes and VEGF in SCI. Combined with the pathologic observation, it suggested that overexpression of HIF-1alpha and its target genes might take part in hypoxia tolerance and vascularity of the injured spinal cord.
Xiaowei
H
H
Laboratory for Conservation and Utilization of Bio-resources, Yunnan University, Kunming, PR China.
Ninghui
Z
Z
Wei
X
X
Yiping
T
T
Linfeng
X
X
D000444:Aldehyde Dehydrogenase / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D005786:Gene Expression Regulation; D006651:Histocytochemistry; D000860:Hypoxia / Q000503:physiopathology; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000032:analysis / Q000235:genetics* / Q000502:physiology*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000235:genetics* / Q000378:metabolism; D000080864:Lactate Dehydrogenase 5; D008297:Male; D018919:Neovascularization, Physiologic; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013116:Spinal Cord / Q000098:blood supply / Q000737:chemistry / Q000503:physiopathology; D013119:Spinal Cord Injuries / Q000150:complications / Q000235:genetics* / Q000503:physiopathology*; D020760:Spinal Cord Ischemia / Q000209:etiology / Q000503:physiopathology; D013997:Time Factors; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics* / Q000502:physiology
C497444:Hif1a protein, rat; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D007527:Isoenzymes; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D007770:L-Lactate Dehydrogenase; D000080864:Lactate Dehydrogenase 5; D000444:Aldehyde Dehydrogenase