Retinal glial cell immunoreactivity and neuronal cell changes in rats with STZ-induced diabetes.
OBJECTIVE
To study whether diabetes could influence glial cells, retinal neurons, and pigment epithelial cells and if so, to evaluate whether any changes could be influenced by aminoguanidine (AG) or probucol (PB).


METHODS
Streptozocin (STZ)-induced diabetic male Wistar rats and age-matched control rats were fed a normal diet, addition of AG in the drinking water (0.5 g/l for diabetic and 1.0 g/l for control rats) or PB in the pellets (1 % w/w) for one or six months. Paraffin embedded retinal sections were incubated in the primary antibodies GFAP, calbindin, RPE65, and Hu, for glial, horizontal, pigment epithelial, and ganglion cells, respectively, and in fluorescent secondary antibodies.


RESULTS
One month after STZ injection, GFAP immunoreactivity was sparse, but after six months it was prominent in glial cells in 5/5 diabetic and 1/7 control retinas (p = 0.015). Neither AG, nor PB influenced this immunoreactivity. Numbers of retinal pigment epithelial cells and cells in the ganglion cell layer, were similar at one and six months of diabetes. By time, the number of horizontal cells decreased (p < 0.001) and branching and numbers of their terminals were reduced (p < 0.001).


CONCLUSIONS
Diabetes for six months resulted in increased glial cell immunoreactivity, and by age, horizontal cell numbers and branching of their terminals decreased, morphological patterns that were unaffected by AG or PB. The numbers of retinal pigment epithelial cells and cells in the ganglion cell layer were unaffected both by age and diabetes.
Agardh
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Department of Ophthalmology, Malmö University Hospital, Sweden. elisabet.agardh@oftal.mas.lu.se
Bruun
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D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage; D064026:Calbindins; D002352:Carrier Proteins; D002452:Cell Count; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism / Q000473:pathology*; D003930:Diabetic Retinopathy / Q000378:metabolism / Q000473:pathology*; D051959:ELAV Proteins; D004791:Enzyme Inhibitors / Q000008:administration & dosage; D005136:Eye Proteins; D019084:Fluorescent Antibody Technique, Indirect; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006146:Guanidines / Q000008:administration & dosage; D008297:Male; D009457:Neuroglia / Q000378:metabolism / Q000473:pathology*; D009474:Neurons / Q000378:metabolism / Q000473:pathology*; D010857:Pigment Epithelium of Eye / Q000378:metabolism / Q000473:pathology; D011341:Probucol / Q000008:administration & dosage; D011506:Proteins / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012160:Retina / Q000378:metabolism / Q000473:pathology*; D064030:S100 Calcium Binding Protein G / Q000378:metabolism; D013311:Streptozocin; D019745:cis-trans-Isomerases; D000099178:Retinoid Isomerohydrolase
D000975:Antioxidants; D064026:Calbindins; D002352:Carrier Proteins; D051959:ELAV Proteins; D004791:Enzyme Inhibitors; D005136:Eye Proteins; D005904:Glial Fibrillary Acidic Protein; D006146:Guanidines; D011341:Probucol; D011506:Proteins; D016601:RNA-Binding Proteins; D064030:S100 Calcium Binding Protein G; D013311:Streptozocin; D019745:cis-trans-Isomerases; D000099178:Retinoid Isomerohydrolase; C004479:pimagedine