High glucose levels down-regulate glucose transporter expression that correlates with increased oxidative stress in placental trophoblast cells in vitro.
OBJECTIVE
To study glucose transporter expression and oxidative stress in placental trophoblasts under hyperglycemic conditions in vitro.


METHODS
Trophoblasts were isolated from term normal human placentas and incubated with Dulbecco's modified eagle medium containing 1000, 2500, and 4500 mg/L glucose for 3 days. At the end of incubation, culture medium was collected. Trophoblast RNA was extracted and mRNA expression of glucose transporters was determined by RNase protection assay. Messenger RNA expression for copper-zinc-superoxide dismutase (CuZn-SOD) was determined by real-time polymerase chain reaction. Lipid peroxide production was determined by measuring malondialdehyde concentration in the culture supernatant. Protein expression of sodium-glucose transporter 2 (SGLT-2) was determined by Western blot analysis.


RESULTS
Messenger RNA expression for glucose transporter 1 (GLUT1) and SGLT-2 were reduced in trophoblast cells incubated with 4500 mg/L glucose compared with those incubated with 1000 and 2000 mg/L glucose. mRNA expression of CuZn-SOD was also decreased in trophoblasts incubated with 4500 mg/L glucose. Malondialdehyde production was significantly increased by trophoblasts incubated with 4500 mg/L glucose compared with those by trophoblasts incubated with 1000 and 2000 mg/L glucose (4.69 +/- 0.60 versus 2.10 +/- 0.29 and 2.89 +/- 0.47 nmol/mg protein; P < .01, respectively).


CONCLUSIONS
Down-regulation of gene expression of glucose transporters correlates with increased lipid peroxide production and decreased superoxide dismutase expression in placental trophoblasts cultured under hyperglycemic conditions.
Department of Obstetrics and Gynecology, Louisiana State University Health Sciences Center, Shreveport, Louisiana 71130, USA.
Hui
H
Li
Yang
Y
Gu
Yanping
Y
Zhang
Michael J
MJ
Lucas
Yuping
Y
Wang
D002478:Cells, Cultured; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects*; D005947:Glucose / Q000008:administration & dosage*; D051272:Glucose Transporter Type 1; D006801:Humans; D008315:Malondialdehyde / Q000378:metabolism; D009004:Monosaccharide Transport Proteins / Q000235:genetics*; D018384:Oxidative Stress / Q000187:drug effects*; D011247:Pregnancy; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013482:Superoxide Dismutase / Q000235:genetics; D014327:Trophoblasts / Q000737:chemistry / Q000378:metabolism*
D051272:Glucose Transporter Type 1; D009004:Monosaccharide Transport Proteins; D012333:RNA, Messenger; C495677:SLC2A1 protein, human; D008315:Malondialdehyde; D013482:Superoxide Dismutase; D005947:Glucose