Cellular composition of an experimental chemical injury to the cornea after exposure to PEGylated hyaluronidase and subtilisin enzymes

Abstract

Introduction. Under conditions of chemical damage to the cornea, its cellular structure is significantly disrupted, requiring emergency highly differentiated regeneration without an expressed proliferative component of inflammation and expansion of immunocompetent cells to gain an antimicrobial potential. For the purpose of pharmacological initiation of these processes, the study of the topical administration of anti-inflammatory enzyme preparations, such as subtilisin and hyaluronidase, is pathogenetically justified. Aim. To study the effect of hyaluronidase and subtilisin, PEGylated (polyethylene glycol – PEG) using the technology of electron beam synthesis on the number of immunocompetent cells in the area of the corneal chemical injury during their subconjunctival and topical administration. Materials and methods. An experimental study of the effect of PEGylated hyaluronidase and subtilisin enzymes, on the cellular composition of the corneal chemical injury was performed on 28 rabbits. Corneal injury was modeled using the Obenberger alkali burn technique. PEG-subtilisin or PEG-hyaluronidase was applied topically or subconjunctivally into the right eye of the animal, depending on the group, the left eye of the animal was used as a control – it was treated with 0.9% NaCl. After the experiment, enucleation was performed. The biomaterial obtained was used to prepare tissue specimens for morphological examination. Results. The total count of cells in the groups of topical and subconjunctival administration of PEG-subtilisin was 43 (40; 52) and 73 (33; 92), and subconjunctival injection of PEG-hyaluronidase – 46 (37; 61), which was higher than the count of cells when using 0.9% NaCl in these groups (p < 0.01) and higher (p < 0.0001) cell numbers in the group of topical administration of PEG-hyaluronidase. The total count of cells with topical application of PEG-hyaluronidase was 15 (13; 16), with topical application of 0.9% NaCl of this group – also 15 (14; 18) (p = 0.38). The neutrophil count with the use of PEG-subtilisin was 1 (1; 2) with topical and 0 (0; 1) with subconjunctival administration, and with the use of PEG-hyaluronidase – 0 (0; 0) both with topical and subconjunctival administration. Conclusion. The administration of PEG-hyaluronidase subconjunctivally and PEG-subtilisin both topically and subconjunctivally leads to an increased migration of immunocompetent cells to the area of the corneal chemical injury, while the migration of neutrophils is insignificant. It is completely absent when PEG-hyaluronidase is injected subconjunctivally. Topical administration of PEG-hyaluronidase does not induce a pronounced cellular response of immunocompetent cells in the area of the corneal chemical injury, and the effect of the application is comparable to that of 0.9% NaCl.