Upregulation of stromal cell-derived factor 1 (SDF-1) expression in microvasculature endothelial cells in retinal ischemia-reperfusion injury.
BACKGROUND
Stromal cell-derived factor 1 (SDF-1) is a potent chemotactic and angiogenic factor that has been proposed to play a role in the development of neovascularization. In this study, we explored the expression of SDF-1 in a rat model of retinal ischemia-reperfusion injury and investigated the possible role of retinal microvasculature endothelium cells in generation of this chemokine.


METHODS
Expression patterns of SDF-1 were studied in retina suffering ischemia-reperfusion insult in Sprague-Dawley rats by elevating the intraocular pressure to 110 mm for 60 minutes. The relative level of SDF-1 mRNA in retinas following 6, 12 and 24 hours reperfusion was determined by semi-quantitative RT-PCR. Immunohistochemical methods were used to detect specific lesions expressing SDF-1. The gene expression of SDF-1 in cultured human retinal microvasculature endothelial cells (HRMEC) under hypoxia conditions was assessed by semi-quantitative RT-PCR. The SDF-1 protein was analyzed by immunocytochemistry and fluorescence-activated cell sorting.


RESULTS
Upregulation of SDF-1 mRNA (at 6, 12, and 24 hours of reperfusion) was observed, with the expression peak occurring at 12 hours. SDF-1 positive cells appeared initially around the retinal vessels,which diffused into the inner retinal layers. Hypoxia enhanced the expression of HIF-1 and SDF-1 mRNA in HRMEC. The production of SDF-1 protein by HRMEC was increased up to 320% after 6 hours of hypoxia, as demonstrated by fluorescence-activated cell sorting.


CONCLUSIONS
The results of our study indicate that endogenous SDF-1 is up-regulated in retinal microvasculature suffering ischemia insult, and that microvasculature endothelial cells are potential contributors for generation of SDF-1 in ischemic retina.
Lai
Pinghong
P
State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, People's Republic of China.
Li
Tao
T
Yang
Jun
J
Xie
Chengyang
C
Zhu
Xiaobo
X
Xie
Hui
H
Ding
Xiaoyan
X
Lin
Shaofen
S
Tang
Shibo
S
D000818:Animals; D002478:Cells, Cultured; D054377:Chemokine CXCL12 / Q000235:genetics / Q000378:metabolism*; D042783:Endothelial Cells / Q000378:metabolism*; D006801:Humans; D000860:Hypoxia / Q000378:metabolism; D051793:Hypoxia-Inducible Factor 1 / Q000235:genetics / Q000378:metabolism; D007150:Immunohistochemistry; D055806:Microvessels / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000378:metabolism*; D012160:Retina / Q000378:metabolism; D012171:Retinal Vessels / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014018:Tissue Distribution; D015854:Up-Regulation
D054377:Chemokine CXCL12; D051793:Hypoxia-Inducible Factor 1; D012333:RNA, Messenger