Immunohistochemical analysis of CD45RO+ T cells and vascular endothelial growth factor expression in cyclosporin A-induced rat gingival tissue

Background: The aim of this study is to evaluate CD4⁺, CD8⁺, and CD45RO⁺ T cells, and vascular endothelial growth factor (VEGF) expression in cyclosporin A (CsA)–induced rat overgrown gingival tissue during an 8‐week period. Methods: Sixty male Sprague‐Dawley rats weighing 200 to 250 g were used in this study. Mandibular first molars were ligated with 3–0 silk suture. The rats received daily doses of 0.09% NaCl (control group) or 10 mg/kg body weight of CsA (test group) by intraperitoneal injections. Five rats from the control group and 10 rats from the test group were sacrificed at each experimental period (2, 4, 6, and 8 weeks after the beginning of CsA treatment). The specimens were examined immunohistochemically. Results: CD4⁺, CD8⁺, and CD45RO⁺ T cells, and VEGF expression were more prevalent in the CsA‐treated group than in the control group (P <0.05). VEGF was significantly correlated with CD4⁺ T cells, CD4⁺/CD8⁺ ratio, and CD45RO⁺ cells (P <0.05). Conclusion: Based on our findings, we conclude that VEGF, a major regulator of angiogenesis, and CD4⁺, CD8⁺, and CD45RO⁺ memory T cells play a key role in CsA‐induced gingival overgrowth.