The Protective Effect of Para-Aminobenzoic Acid in HypoxiaInduced Apoptosis of Conjunctiva and Cornea Cells in vivo

Purpose: to evaluate the effects of acute hypoxic hypoxia on eye tissue cells in adult rats and determining the effectiveness of 0.007 % solution of para-aminobenzoic acid (PABA) for apoptotic damage to the tissues of the ocular surface in rats.

Materials and methods. In the experiment, 27 male Wistar rats (54 eyes) were used, divided into 5 groups. Group I — intact control, Group II — hypoxic control after 1 hour, Group III — hypoxic control after 3 hours, Group IV — with the injection of the drug 1 hour after hypoxia, Group V — injection of the drug 24 hours before hypoxia. The identification of apoptotic cells in the tissues of the eye was performed by the TUNEL method on frozen sections of the eye stained with Hoechst 33342 nuclear fluorescent dye. The localization and fluorescence intensity of the damaged cells was analyzed under a fluorescence microscope using the Image J. computer program.

Results. Under the conditions of simulated acute hypoxic hypoxia, apoptotic lesions of the conjunctiva, corneal epithelium, choroid, and photoreceptor layer of the retina were observed. In group II, the number of damaged cells in the conjunctiva was 67 %, and in group III it was 120 % more compared to group I — the norm (p < 0.05). With the injection of PABA before hypoxia, there were no significant differences compared with the norm (group I) in the state of the affected cells in the conjunctiva. In the group of animals (group III) with the injection of PABA after hypoxia after 1 h, the number of damaged cells does not statistically differ from group II (hypoxic control after 1 h), but significantly lower than in group III (hypoxic control after 3 hours). The same pattern is observed in the corneal epithelium.

Conclusion. Para-aminobenzoic acid (0.007 %) has a prophylactic and therapeutic effect, preventing and stabilizing the development of apoptosis of conjunctival cells and anterior corneal epithelium induced in experimental acute hypoxic hypoxia. 

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