Abstract
Purpose: :
Glaucoma describes ocular diseases where a loss of retinal ganglion cells (RGCs) occurs. Recently an autoimmune involvement in the pathogenesis has been discussed. In this project aqueous humor of animals with Experimental Autoimmune Glaucoma (EAG) was analyzed with proteomic methods. In the EAG model RGC loss is caused by antigen immunization.
Methods: :
Lewis rats were immunized with myelin basic protein (MBP) or optic nerve homogenate (ONH) in combination with pertussis toxin and Freund’s adjuvant. In study I (MBP, n=10 and ONH, n=10) rats were euthanized 5 weeks after immunization and aqueous humor was collected. A control group (C, n=10) received only pertussis toxin and Freund’s adjuvant.In study II (MBP, n=11, ONH, n=11 and C, n=11) animals received additional 50% doses of immunization after 4 and 8 weeks and were euthanized after 10 weeks. Aqueous humor was collected in both studies.In both studies eyes were enucleated, fixed, and retinal flatmounts were stained with Kresylblue to detect RGCs. All aqueous humor samples (5 µl) were prefractionated using microbeads (Bruker, Germany) and analyzed using SELDI-TOF ProteinChips (Biorad, Hercules, USA). Data were analyzed by multivariate statistical techniques
Results: :
Study I revealed a significant difference between protein profiles of samples from animals immunized with ONH and control animals (P=0.05). No significant difference was observed between profiles of MBP immunized animals and controls (P=0.11).In study II a significant RGC loss was observed in rats immunized with MBP (P=0.0001) and ONH (P=0.003). Protein patterns in animals immunized with MBP were significantly deviating from controls (P=0.02), whereas profiles of the ONH group showed no significant difference (P=0.27).Significant biomarkers were detected in both studies.
Conclusions: :
A significant RGC loss could be observed after immunization with MBP or optic nerve homogenate as well as changes in the aqueous humor protein pattern.The study shows that both duration and the number of immunizations seem to influence the aqueous humor protein profiles in the EAG animal model.
Keywords: aqueous • proteomics • pathology: experimental