[Effects and mechanism of electroacupuncture stimulation on the survival of multi-territory perforator flaps in rats]

Objective: To explore the effects and mechanism of electroacupuncture stimulation on the survival of multi-territory perforator flaps in rats. Methods: This study was an experimental study. Thirty male Sprague-Dawley rats aged 8-10 weeks were collected and divided into electroacupuncture stimulation group and control group according to the random number table method, with 15 rats in each group. Doppler blood flow detectors were used to explore the positions of the dorsal deep circumflex artery, posterior intercostal artery, and thoracodorsal artery in the two groups of rats, and a multi-territory perforator flap was designed and resected with the dorsal deep circumflex artery as the pedicle after ligation of the posterior intercostal artery and thoracodorsal artery, and the flap was replanted in situ. Before the operation, the skin in the area containing choke vessels at the junction between the angiosomes of the thoracodorsal artery and posterior intercostal artery (i.e. the choke zone Ⅱ) in the flaps of rats in electroacupuncture stimulation group was subjected to electroacupuncture stimulation for 1 hour per day for 7 consecutive days, while the flaps of rats in control group received no electroacupuncture stimulation. Seven days after the operation, the survival status of the flaps of all rats in the two groups was observed and the flap survival rate was calculated; the skin tissue from the choke zone Ⅱ was collected and stained with hematoxylin-eosin to observe the microvascular neogenesis and calculate the microvessel density (with sample number of 3). Immunohistochemical staining was performed to observe the expression and distribution of vascular endothelial growth factor (VEGF), and Western blotting was used to detect the protein expression of VEGF (with sample number of 3). Results: Seven days after the operation, the flaps of rats in control group were partially blackened and necrotic, while those in electroacupuncture stimulation group survived with almost no necrosis. The flap survival rate of rats in electroacupuncture stimulation group was (92.1±2.1)%, which was significantly higher than (85.2±1.2)% in control group (t=-10.95, P<0.05). Seven days after the operation, compared with those in control group, the number of new microvessels in the skin tissue in the choke zone Ⅱ of the flaps in rats of electroacupuncture stimulation group increased significantly. The microvessel density in the skin tissue in the choke zone Ⅱ of the flaps in rats of electroacupuncture stimulation group was (21.4±3.0) vessels/mm², which was significantly higher than (11.5±3.7) vessels/mm² in control group (t=-7.34, P<0.05). Seven days after the operation, compared with those in control group, the expression of VEGF in the vascular area of the skin tissue in the choke zone Ⅱ of the flaps in rats of electroacupuncture stimulation group was significantly increased, and the protein expression of VEGF was significantly increased (t=12.56, P<0.05). Conclusions: Electroacupuncture stimulation can increase the expression of VEGF in choke zone Ⅱ of the multi-territory perforator flaps in rats, improve the blood supply at the distal end of flaps through promoting morphological changes of blood vessels in this zone, thus increasing the survival rates of flaps.