Polyol formation in cell lines of rat retinal capillary pericytes and endothelial cells (TR-rPCT and TR-iBRB).
OBJECTIVE
The two most widely investigated animal models for diabetic retinopathy (DR) are the rat and dog. In dogs, aldose reductase (AR) is present only in retinal capillary pericytes and their destruction has been linked to polyol accumulation and resulting apoptosis. Since both rat capillary pericytes and endothelial cells have been reported to contain AR, the role of polyol pathway activity in capillary cell destruction has been investigated in rat retinal capillary pericyte (TR-rPCT) and endothelial (TR-iBRB) cells.


METHODS
TR-rPCT and TR-iBRB cell lines were recloned and their identities were reconfirmed by characteristic immunostaining. Cells were cultured up to 72 h in media containing 50 mM glucose or galactose with/without the AR inhibitors or a sorbitol dehydrogenase inhibitor (SDI) or with 30 mM 3-fluoro-3-deoxyglucose. Polyol levels were determined by HPLC or (19)F-NMR. Apoptosis was detected with TUNEL/DAPI staining.


RESULTS
Smooth muscle actin is present only in pericytes while only endothelial cells stain for von Willebrand factor and accumulate acetylated low-density lipoprotein. AR is present in both cells but AR levels are lower in endothelial cells. Aldehyde reductase is also present in both cells. Cells cultured in 50 mM glucose or galactose show significant polyol accumulation in pericytes but endothelial cells show little accumulation of galactitol and no accumulation of sorbitol. Sorbitol accumulation in pericytes resulted in increased cellular permeability and increased TUNEL staining, which was reduced by AR inhibition.


CONCLUSIONS
Although both rat retinal pericytes and endothelial cells contain AR, sorbitol accumulation and TUNEL staining primarily occur in pericytes and are inhibited by AR inhibitors.
Kador
Peter F
PF
Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, 986025 Nebraska Medical Center, Omaha, NE 68198-6025, USA. pkador@unmc.edu
Randazzo
James
J
Blessing
Karen
K
Makita
Jun
J
Zhang
Peng
P
Yu
Kuang
K
Hosoya
Ken-Ichi
K
Terasaki
T
T
D000199:Actins / Q000378:metabolism; D000449:Aldehyde Reductase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000818:Animals; D017209:Apoptosis; D002196:Capillaries / Q000378:metabolism; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000378:metabolism; D004376:Galactitol / Q000378:metabolism; D005690:Galactose / Q000378:metabolism / Q000633:toxicity; D005947:Glucose / Q000378:metabolism / Q000633:toxicity*; D020287:In Situ Nick-End Labeling; D007211:Indoles; D007064:L-Iditol 2-Dehydrogenase / Q000037:antagonists & inhibitors / Q000378:metabolism; D020286:Pericytes / Q000201:enzymology / Q000378:metabolism*; D051381:Rats; D055647:Rats, Transgenic; D012160:Retina / Q000378:metabolism; D012171:Retinal Vessels / Q000378:metabolism; D013012:Sorbitol / Q000378:metabolism; D013194:Staining and Labeling; D013402:Sugar Alcohols / Q000378:metabolism*; D014841:von Willebrand Factor / Q000378:metabolism
D000199:Actins; D007211:Indoles; D013402:Sugar Alcohols; D014841:von Willebrand Factor; D004376:Galactitol; C007293:DAPI; D013012:Sorbitol; D007064:L-Iditol 2-Dehydrogenase; D000449:Aldehyde Reductase; D005947:Glucose; D005690:Galactose