Mechanisms of the influence of conditioned medium of cultured stem cells on the development of pathological angiogenesis in the eye cornea in experiment

Abstract

In recent decades, due to increasing number of diseases associated with the development of newly formed vessels, the interest to pathological angiogenesis in eye tissues has been growing. Traditional, conservative methods for treatment of corneal neovascularization are not sufficiently effective. A possible solution may be the use of paracrine factors secreted by mesenchymal stem cells during cultivation in a conditioned medium (CW). The aim of this study was to assess the effect of CW peptides on vascular leukoma induced by chemical burn of rat eyes and to evaluate the effect of CW on the functional activity of neutrophils.

Methods. The study was performed on 48 rats (48 eyes) and included several stages. At the first stage, chemical corneal burn was modeled in all animals. At the second stage, corneal burns were treated. Based on the method of treatment at the second stage, a control group (22 rats, 22 eyes) and an experimental group (22 rats, 22 eyes) were formed. The experimental group was divided into 2 subgroups. The first subgroup rats (n = 11, 11 eyes) were treated with CW peptides of the entire fraction. The second subgroup rats (n = 11, 11 eyes) received a CW peptide fraction of up to 30 kDa. In the control group, the culture medium was used as a treatment.

Results. According to the results of ophthalmoscopy and histological studies on days 14 and 30, no changes were observed in the control group. Multiple newly formed corneal vessels (mainly large vascular trunks) with stromal opacities in their projection were detected. The corneal epithelium was unchanged; however, the cornea itself was thinned. A formed vascularized corneal leukoma was observed that was evident as subepithelial fibroplasia and corneal neovascularization. In the experimental group by the 14th day of CW peptide instillations into the conjunctival cavity, ophthalmoscopy showed a decrease in the number of newly formed vessels, and corneal opacities disappeared in the projection of the deserted vessels. In most of rats in the experimental groups on the 30th day of the treatment, newly formed vessels were not found; only individual vascular trunks remained, which had previously formed powerful anastomoses with other newly formed vessels. According to the results of chemiluminescence analysis, a fraction of up to 30 kDa inhibited the functional activity of neutrophils, including by changing the activity of intracellular membrane enzymes responsible for the transmission of receptor signals into the cell.

Conclusion. The results showed that the peptide solution is promising for the treatment of such a complex pathology as corneal neovascularization.