[Expression and significance of hypoxia-inducible factor-1α and vascular endothelial growth factor and receptor 2 in stage 3 pressure injury of rats].

Objective: To analyze the expression and relationship of hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF) and kinase insert domain receptor (KDR) in local skin tissues of pressure injury and investigate the possible mechanism of stage 3 pressure injury refractory wound.
Methods: Forty male SD rats were randomly divided into normal control group, compressed 3 d, 5 d, 7 d, and 9 d groups. Stage 3 pressure injury animal model were established by magnet compression. The morphology of skin was observed by HE staining. The expression of VEGF was detected by immunohistochemistry. The expression levels of HIF-1α, VEGF and KDR protein in skin tissue were detected by Western blot. One-way analysis of variance and LSD test were performed on the data.
Results: ①The HE results showed that compared with the normal control group, the epidermis of the compressed group was gradually thickened, the number of blood vessels was decreased, the collagen arrangement disordered and inflammatory cells infiltration were increased. ②Immunohistochemical results showed that the expression of VEGF protein in the 3 d group was significantly higher than that in the normal control group (P＜0.01). The expression of VEGF protein in the skin tissue of 5 d, 7 d and 9 d groups was lower than that in normal control group (P＜0.05). WB results were consistent with immunohistochemistry results. ③WB results showed that the expression of HIF-1α in the skin tissues of the rats in 3 d, 5 d and 7 d groups was higher than that in the normal control group (P＜0.01 or P＜0.05). The expression of KDR protein was lower than that of the normal control group (P＜0.05 or P＜0.01).
Conclusion: HIF-1α mediated reduction of VEGF and KDR protein expression and decreased tissue angiogenesis may be one of the important causes of chronic dysfunction of stage 3 pressure injury.