The effect of juglans regia (walnut leaf) extract on ischemia-reperfusion injury in the rat epigastric artery flap

Introduction and Objectives: Reconstructive surgery aims to restore congenital or acquired tissue defects both functionally and aesthetically. The flaps used in this field provide an important treatment option for large tissue defects, as they are transferred with their own vascular pedicles. However, one of the most common problems encountered in flap surgery is ischemia-reperfusion (I/R) injury that develops during the operation. The increased production of free radicals and inflammation during reperfusion can lead to flap necrosis. In this study, the protective role of Juglans regia (walnut leaf) extract against I/R injury in the rat inferior epigastric artery flap was investigated, focusing on its antioxidant and anti-inflammatory properties. Materials and Methods: The study was conducted on Wistar albino rats, which were divided into control, I/R, and Juglans regia-treated groups. The plant extract was prepared using an appropriate extraction protocol and administered at predetermined doses. A rat inferior epigastric artery pedicled flap model was established; the flaps were subjected to ischemia followed by reperfusion. Macroscopically, flap survival area was calculated; histopathologically, neutrophil infiltration and changes in vessel diameter were examined. Biochemical parameters including MDA, MPO, SOD, and GPx levels were measured, and the mRNA expression of SOD, iNOS, COX-2, and MMP-1 genes was evaluated by qPCR. A significance level of p<0.05 was accepted for all statistical analyses. Results: In the Juglans regia-treated groups, the flap survival area increased significantly (p<0.001). Histopathological analysis revealed a marked reduction in neutrophil infiltration (p<0.001) and a decrease in vessel diameter in the treatment group. Biochemically, MDA levels were significantly reduced in the treatment group (p<0.001), while MPO levels also decreased (p<0.001). In contrast, SOD and GPx activities were significantly increased (p<0.001). Gene expression analyses demonstrated a significant upregulation of SOD (p<0.001) and a significant downregulation of iNOS and COX-2 (p<0.001), while MMP-1 gene expression increased in the treatment group (p<0.001). Cell culture assays confirmed that the extract did not exhibit cytotoxic effects at the tested doses (p>0.05). These results indicate that Juglans regiaextract exerts protective effects on oxidative stress and inflammatory responses. Conclusion: This study demonstrated that Juglans regia (walnut leaf) extract provides a protective effect against I/R injury through its strong antioxidant properties. Administration of the extract reduced oxidative stress markers, increased flap viability, and supported tissue healing. Moreover, the increased MMP-1 expression suggests that tissue remodeling may be stimulated by the extract's effects. In conclusion, Juglans regia extract has potential as a natural agent to support flap viability in reconstructive surgery. Keywords: Juglans regia, ischemia-reperfusion injury, antioxidant, flap viability, reconstructive surgery