Effect of N-acetylcysteine on the early expression of inflammatory markers in the retina and plasma of diabetic rats.
OBJECTIVE
The aim of this study is to investigate markers of inflammation and oxidative stress in an early model of diabetic retinopathy, correlate retinal and plasma results and evaluate the influence of treatment by N-acetylcysteine (NAC), a free radical scavenger.


METHODS
Four groups were studied: control (C), streptozotocin (STZ)-induced diabetic rats (D), STZ rats following 8 weeks of NAC (DT), and control rats following 8 weeks of NAC (CT). Plasma levels of free 15-F2t-isoprostane (15-F-2t-IsoP), superoxide dismutase (SOD) and tumour necrosis factor-alpha (TNF-alpha) were obtained. Primary antibodies against macrophages (ED-1), microglia (Ox-42), pericytes (NG-2), endothelial and perivascular cells (IB-4), haem oxygenase 1 (HO-1) and vascular endothelial growth factor (VEGF) were used.


RESULTS
Expression of NG-2 was robust in C, CT, DT, and mild in D. The intensity of IB-4 was higher in D and DT compared with the C and CT. Ox-42 and ED-1 expression was higher in the D than in the DT, C or CT. Expression of VEGF and HO-1 was non-specific across the four groups. Plasma levels of 15-F-2t-IsoP and TNF-alpha were higher in the D as compared with the C, CT and DT. SOD levels were lower in the D when compared with the C, CT and D.


CONCLUSIONS
Macrophage/microglia activation, pericyte loss and endothelial/perivascular cell changes occur early in the pathogenesis of DR. These changes are associated with an increase in plasma markers of oxidative stress and inflammation and are minimized by treatment with NAC. The results suggest that therapies that reduce free radicals will help minimize the early events in diabetic retinopathy in the STZ model.
Tsai
Gina Y
GY
Ophthalmology and Visual Sciences, Faculty of Medicine, University of British Columbia, Columbia, Canada.
Cui
Jing Z
JZ
Syed
Husnain
H
Xia
Zhengyuan
Z
Ozerdem
Ugur
U
McNeill
John H
JH
Matsubara
Joanne A
JA
D000111:Acetylcysteine / Q000627:therapeutic use*; D000818:Animals; D015415:Biomarkers / Q000097:blood*; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D003930:Diabetic Retinopathy / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D015237:Dinoprost / Q000031:analogs & derivatives; D004730:Endothelium, Vascular / Q000378:metabolism / Q000473:pathology; D004797:Enzyme-Linked Immunosorbent Assay; D019084:Fluorescent Antibody Technique, Indirect; D016166:Free Radical Scavengers / Q000627:therapeutic use*; D007124:Immunoenzyme Techniques; D007249:Inflammation / Q000378:metabolism / Q000473:pathology; D028421:Isoprostanes / Q000097:blood; D008264:Macrophages / Q000378:metabolism / Q000473:pathology; D008297:Male; D017628:Microglia / Q000378:metabolism / Q000473:pathology; D018384:Oxidative Stress; D020286:Pericytes / Q000378:metabolism / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D012160:Retina / Q000187:drug effects* / Q000378:metabolism; D013482:Superoxide Dismutase / Q000097:blood; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
D015415:Biomarkers; D016166:Free Radical Scavengers; D028421:Isoprostanes; D014409:Tumor Necrosis Factor-alpha; C075750:8-epi-prostaglandin F2alpha; D015237:Dinoprost; D013482:Superoxide Dismutase; D000111:Acetylcysteine