Aldose reductase inhibitor fidarestat counteracts diabetes-associated cataract formation, retinal oxidative-nitrosative stress, glial activation, and apoptosis.
This study was aimed at evaluating the potent and specific aldose reductase inhibitor fidarestat, on diabetes-associated cataract formation, and retinal oxidative-nitrosative stress, glial activation, and apoptosis. Control and streptozotocin-diabetic rats were treated with or without fidarestat (16 mg kg(-1)d(-1)) for 10 weeks after an initial 2-week period without treatment. Lens changes were evaluated by indirect ophthalmoscopy and portable slit lamp. Nitrotyrosine, poly(ADP-ribose), and glial fibrillary acidic protein expression were assessed by immunohistochemistry. The rate of apoptosis was quantified in flat-mounted retinas by TUNEL assay with immunoperoxidase staining. To dissect the effects of high glucose exposure in retinal microvascular cells, primary bovine retinal pericytes and endothelial cells were cultured in 5 or 30 mM glucose, with or without fidarestat (10 microM) for 3-14 days. Apoptosis was assessed by TUNEL assay, nitrotyrosine and poly(ADP-ribose) by immunocytochemistry, and Bax and Bcl-2 expression by Western blot analyses. Fidarestat treatment prevented diabetic cataract formation and counteracted retinal nitrosative stress, and poly(ADP-ribose) polymerase activation, as well as glial activation. The number of TUNEL-positive nuclei (mean +/- SEM) was increased approximately 4-fold in diabetic rats vs. controls (207+/-33 vs. 49+/-4, p<0.01), and this increase was partially prevented by fidarestat (106+/-34, p<0.05 vs. untreated diabetic group). The apoptotic cell number increased with the prolongation of exposure of both pericytes and endothelial cells to high glucose levels. Fidarestat counteracted nitrotyrosine and poly(ADP-ribose) accumulation and apoptosis in both cell types. Antiapoptotic effect of fidarestat in high glucose-exposed retinal pericytes was not associated with the inhibition of Bax or increase in Bcl-2 expression. In conclusion, the findings, i) support an important role for aldose reductase in diabetes-associated cataract formation, and retinal oxidative-nitrosative stress, glial activation, and apoptosis, and ii) provide a rationale for the development of aldose reductase inhibitors, and, in particular, fidarestat, for the prevention and treatment of diabetic ocular complications.
Drel
Viktor R
VR
Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA.
Pacher
Pal
P
Ali
Tayyeba K
TK
Shin
Jeho
J
Julius
Ulrich
U
El-Remessy
Azza B
AB
Obrosova
Irina G
IG
D000449:Aldehyde Reductase / Q000037:antagonists & inhibitors*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000032:analysis; D001786:Blood Glucose / Q000032:analysis; D015153:Blotting, Western; D002386:Cataract / Q000188:drug therapy* / Q000209:etiology / Q000517:prevention & control; D003921:Diabetes Mellitus, Experimental / Q000139:chemically induced / Q000150:complications / Q000378:metabolism; D003930:Diabetic Retinopathy / Q000188:drug therapy / Q000209:etiology / Q000517:prevention & control; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D048289:Imidazolidines / Q000627:therapeutic use*; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D009457:Neuroglia / Q000187:drug effects* / Q000378:metabolism; D009887:Ophthalmoscopy; D018384:Oxidative Stress / Q000187:drug effects*; D011065:Poly(ADP-ribose) Polymerases / Q000032:analysis; D051381:Rats; D012160:Retina / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D013311:Streptozocin; D014443:Tyrosine / Q000031:analogs & derivatives / Q000032:analysis; D051028:bcl-2-Associated X Protein / Q000032:analysis
D051017:Apoptosis Regulatory Proteins; D001786:Blood Glucose; D005904:Glial Fibrillary Acidic Protein; D048289:Imidazolidines; D051028:bcl-2-Associated X Protein; C002744:3-nitrotyrosine; D014443:Tyrosine; D013311:Streptozocin; C077139:fidarestat; D000449:Aldehyde Reductase; D011065:Poly(ADP-ribose) Polymerases