Changes of alpha-2-macroglobulin activity in tear fluid in experimental retinal pigment epithelium atrophy of rabbits

Abstract

Purpose. To assess the validity of alpha-2-macroglobulin ( 2-MG) activity and endothelin-1 (ET-1) concentration for the characterization of local metabolic disorders in experimental retinal pigment epithelium atrophy (RPE).Material and methods. To reproduce RPE atrophy, 22 New Zealand Albino rabbits were given a subretinal injection of bevacizumab or saline. Tear fluid was collected before the injection and 3 months after it. In the second series of the experiment, tear fluid was also collected on the 3rd, 7th, 14th, 21st and 28th days after bevacizumab injection. Tear fluid was analyzed for the activity of 2-MG using the fermentation method and for ET-1 concentration by the immunoenzymatic method.Results. 3 months after bevacizumab injection, 2-MG activity in the tear remained normal, while after saline injection it was, on average, twice as high as the initial one. ET-1 concentration showed a significant increase of over 1.5 times on the 3rd day after bevacizumab injection both in the tear of the operated and the contralateral eyes.Conclusion. Subretinal bevacizumab injection had no significant lasting damaging effect on the retina, as opposed to saline injection that led to an increase of 2-MG activity in the tear. A transitory increase of ET-1 concentration in the tears after bevacizumab injection may indicate vascular tone elevation in the eye during this period. The study of 2-MG activity and ET-1 concentration in the tear may be used to monitor local metabolic shifts in experimental RPE atrophy development, as well as to assess the post-transplantation process and therapy adequacy.