【Animal modeling】-The role of stromal cell-derived factor-1 and chemokine receptor 4 in the rejection of rat corneal transplantation

  Objective: To investigate the expressions of stromal cell-derived factor-1 (SDF-1) and stromal cell-derived factor-1 (CXCR4) in rat corneal tissue and their roles in immune rejection after keratoplasty.

  METHODS: Fifteen Wistar rats were selected as normal control group; 22 Wistar rats were selected for autologous keratoplasty as autologous group; 22 SD rats and 44 Wistar rats were selected, SD rats were used as donors, and Wistar rats were used as donors. Rats were recipients of penetrating keratoplasty. After the operation, 22 rats were randomly selected and included in the Dianbisu group, and Dianbisu eye drops (twice a day) were instilled in the operated eyes. The remaining 22 rats were included in the allograft group. Drip the same amount of normal saline for one month. The corneal grafts in each group were evaluated clinically according to Larkin's method; the corneal grafts were taken on the 5th and 9th days after the operation, respectively, and the histopathological observation, immunohistochemical examination, and real-time fluorescence quantitative PCR were performed.

  RESULTS: No rejection occurred in the autologous group, and the corneal survival time in the Dianbisu group was 24±0.32 d, which was much higher than that in the allogeneic group, 10±0.36 d (P<0.001). Histopathological examination revealed a large number of inflammatory cell infiltration and neovascularization in the cornea of the allogeneic group. The expression levels of SDF-1 and CXCR4 mRNA in the corneal tissue of the allogeneic group were significantly increased (P<0.001 on the 5th day, P<0.01 on the 9th day), and the Dianbishu group was significantly lower than that in the allogeneic group. Immunohistochemical examination showed that SDF-1/CXCR4 was mainly expressed in the epithelial layer and stromal layer of the corneal graft, and the contents of SDF-1 and CXCR4 in the corneal tissue of the allogeneic group were significantly increased.

  Conclusion: SDF-1/CXCR4 may be involved in early rejection after corneal transplantation in rats, and the mechanism may be that SDF-1 specifically induces the maturation of CXCR4+ cells and chemotaxis towards the site of rejection, and promotes corneal neovascularization.