Abstract
Purpose: :
Antibodies against heat shock proteins have been identified in sera of glaucoma patients in several studies. The aim of this study was to analyze if immunization with heat shock protein 60 (HSP60) can cause retinal ganglion cell loss in rats and detect changes in antibody profiles.
Methods: :
Lewis rats were divided into two groups. Ten animals were immunized with HSP60 (=100 µg) plus Freund’s adjuvant and pertussis toxin. All animals in this group received a second immunization after four weeks. Healthy animals that received no immunization served as control group (n=9). All rats were euthanized after eight weeks.Intraocular pressure (IOP) was measured in all animals one week before the immunization and four and seven weeks after immunization using a TonoLab®. Fundus pictures were taken with a retinal camera at the same time points.Blood was collected in all animals during the duration of the study: before immunization and four and eight weeks after immunization. The serum was used to detect antibody patterns against bovine retinal antigens using Western blotting techniques. These patterns were analyzed by multivariate statistical techniques.All eyes were fixed in 4% paraformaldehyed after eight weeks and flatmounts were stained with Brn-3a to detect retinal ganglion cell nuclei. A semi-automated ganglion cell (RGC) density count was performed.
Results: :
No significant differences could be found in IOP between all groups during the duration of the study. We could not detect any abnormal signs, such as bleeding, on the fundus photos in both groups during the course of the study.The histological analysis of the retinal flatmounts showed a significant RGC loss in animals immunized with HSP60 (P=0.02) and the statistical analysis showed a significant difference between the antibody profiles of both groups (P<0.05).
Conclusions: :
Immunization with heat shock protein 60 showed a significant RGC loss and changes in antibody profiles in an animal model. Our data might lead to a better understanding of the pathogenesis of glaucoma.
Keywords: autoimmune disease • retina • pathology: experimental