The effect of platelet rich plasma and semi-synthetic sodium alginate hydrogel on corneal wound healing after corneal alkali burns in rats

Objective: Our objective is to determine the effect of semi-synthetic sodium alginate hydrogel and its combination with platelet-rich plasma (PRP) on the histopathological, biochemical, and other diagnostic modality, optical coherence tomography. Materials and Methods: 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, semi-synthetic sodium alginate hydrogel, and a combination of PRP and hydrogel three times daily. Degree of corneal opacity (CO), Corneal epithelial staining (CES), Corneal epithelial defects percentage (CEDP), ciliary hyperemia (CH), neovascularization size (NVS), and extent (NVE) were evaluated. AS-OCT was performed at nine days, and then subjects were sacrificed. Histological examination and enzyme-linked immunosorbent assay were performed to detect the concentration of IL-1β and MMP-9 in the cornea. Results: There was no statistical difference between groups regarding CEDP, CO, CES, CH, NVS, and NVE on the first day after corneal alkali burn (p> 0,05). At the last examination, CO was significantly lower in the PRP group than the sham group (p=0,044), while groups were similar in terms of NVS (p>0,05). Groups were similar in terms of tissue MMP-9 levels (p>0,05), while there was a significant difference between groups in tissue IL-1𝛽 levels (p<0,001). In PRP and PRP+Hydrogel group, the level of IL-1𝛽 was significantly lower than sham group (p=0,043 and p=0,036, respectively). There was a significant epithelial necrosis difference between groups, and it was least in the PRP+Hydrogel group (p=0,003). Epithelial thickness was highest in the PRP+Hydrogel (p=0,002). CEDP was significantly different at the last visit between groups (p=0,042). The fastest epithelial closing rate was in the PRP+Hydrogel group in respect to others (p=0,026). There was a significant negative correlation between tissue MMP-9 levels and corneal solidity and corneal area in AS-OCT measurements (p=0,012 and p=0,027, respectively). Conclusion: Topical hydrogel application alone was not significantly effective in the corneal wound healing process. However, when topically applied in conjunction with PRP, it further increases epithelial closure rate and neovascularization effect but not inflammation and corneal opacity when compared to PRP. In addition, citrate solution in the PRP tube as an anticoagulant was not effective. The combination of PRP and hydrogel may further increase epithelial thickness while decreasing epithelial necrosis. After image processing of the AS-OCT scans, new parameters can be used for rats' corneal wound healing process.