Effects of Traditional Chinese Medicine, Dilong Injection, on Random Skin Flap Survival in Rats

Background: Dilong injection as a medicinal preparation extracted from earthworm in traditional Chinese medicine, is used to activate blood circulation and remove blood stasis. In this research, we aim to investigate its potential effect on random skin flap survival in rat models. Materials and methods: McFarlane flaps were established in 60 male Sprague-Dawley rats randomly divided into two groups: the control group and the Dilong injection group. Diong injection group was injected with the Diong injection (4 mL/kg) once a day for seven days, and the control group was given an equal volume of saline solution. After seven days, flaps were obtained and stained with Hematoxylin and Eosin. Histological examination was done to determine changes in histology such as thickness of granulation tissue, tissue edema, neutrophil infiltration, and the microvascular density (MVD). In addition, immunohistochemical detection was carried out to show vascular endothelial growth factor (VEGF) expression level. Results: Compared with the control group, the Dilong group exhibited more fibroblastic proliferation, thinner neutrophil infiltration with less edema through histological examination. The MVD and the VEGF expression of flaps were significantly higher. The mean superoxide dismutase activity was evidently higher in the Dilong group than in the control group, while the mean MDA level was lower. Conclusions: According to the comparison made between the two groups for histological and immunohistochemical evaluation, the Dilong injection group has potential effects on the survival of random skin flaps in rat models.