The effect of platelet-rich plasma and sodium alginate hydrogel on corneal wound healing after corneal alkali burns in rats with computer-assisted anterior segment optical coherence tomography image analysis

Abstract

Our objective was to determine the effect of a semi-synthetic sodium alginate hydrogel and its combination with platelet-rich plasma (PRP) on histopathological, biochemical, clinical, and anterior segment optical coherence tomography (AS-OCT) data. Alkali chemical burn of the cornea was induced. Injured rats were randomly divided into five equal groups and topically treated with phosphate-buffered saline (sham), platelet-rich plasma (PRP), 0.5% sodium citrate, a semi-synthetic sodium alginate hydrogel, or a combination of PRP and hydrogel (combined group) three times daily. The degree of corneal opacity (CO), corneal epithelial staining (CES), percentage of corneal epithelial defects (CEDP), degree of ciliary hyperemia (CH), neovascularization size (NVS), and extent of neovascularization (NVE) were evaluated. AS-OCT was performed at nine days, and then rats were sacrificed. Histological examination and enzyme-linked immunosorbent assays were performed to detect the concentrations of IL-1β and MMP-9 in the cornea. There were no significant differences between the groups regarding CEDP, CO, CES, CH, NVS, or NVE on the first day after corneal alkali burn injury (p > 0,05). At the last examination, CO was significantly lower in the PRP group than in the sham group (p = 0,044), while the CO concentrations were similar in terms of NVS (p > 0,05). Similarly, in terms of tissue MMP-9 levels, there were no significant differences between groups (p > 0,05). However, there was a significant difference in tissue IL-1β levels between the groups (p < 0,001). In the PRP and combined groups, the level of IL-1β was significantly lower than that in the sham group (p = 0,043 and p = 0,036, respectively). There was a significant difference in epithelial necrosis between the PRP, and it was the lowest in the combined group (p = 0,003). Epithelial thickness was highest in the combined group (p = 0,002). CEDP was significantly different at the last visit between the groups (p = 0.042). The fastest epithelial closing rate was observed for the combined group (p = 0,026). There was a significant negative correlation between tissue MMP-9 levels and corneal solidity and between tissue MMP-9 levels and the corneal area according to the AS-OCT measurements (p = 0,012 and p = 0,027, respectively). When used alone, topical hydrogel application did not significantly enhance the healing of corneal wounds. However, when combined with PRP, it leads to an increased rate of epithelial closure and neovascularization. This combination did not exacerbate inflammation or corneal opacity compared to PRP alone. The anticoagulant citrate solution in the PRP tube did not prove effective. The synergistic use of PRP and hydrogel could enhance epithelial thickness and reduce epithelial necrosis. The use of new parameters for corneal wound healing assessment was facilitated through AS-OCT image processing.