Department of Hand and Microsurgery, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China.
Department of Hand and Microsurgery, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China.
Gene. 2019 Mar 1;687:99-108. doi: 10.1016/j.gene.2018.11.019. Epub 2018 Nov 15.
The aim of this study was to explore the hemodynamic and morphological changes of the choke vessels, and to investigate the role of HIF-1α in the flap adaptation to hypoxic and choke vessel transformation after multi-territory perforator flap transplantation.
Animal model of single pedicle multi-territory perforator flap was established in the back of SD rats and the blood supply characteristics were studied by gelatin-oxide perfusion technique. HE staining and stereomicroscope were used to observe vascular changes. Afterward, the influence of hypoxia on cell proliferation and apoptosis were detected by MTT assay and flow cytometry, respectively. Besides, the expression of HIF-1α, iNOS and VEGF expression of HUVECs under hypoxia were detected by qRT-PCR and Western blot.
The results revealed that all the choke vessels immediately began to expand after operation. The day after operation, some of the choke vessels continued to grow and expand, turning into the true anastomosis, while the others gradually dwindled and finally disappeared. Compared with the control group, the day after transplantation, the expression levels of both HIF-1α and iNOS were significantly increased. The only different was that HIF-1α was then maintained a high level, iNOS was significantly decreased aftertimes. What's more, the expression of VEGF was increased to the maximum at 3 days after operation and then decreased. In HUVECs, hypoxia increased the expression of HIF-1α, iNOS and VEGF protein. Besides, it also promoted the proliferation and inhibited the apoptosis. In addition, we also found that hypoxia-induced VEGF and iNOS upregulation is mediated by HIF-1α overexpression and HIF-1α knockout can reverse the effects induced by hypoxia.
We found that HIF-1α may participate in the early vascular dilatation of transregional skin flap by inducing iNOS expression and promoting the reconstruction of choke vessels through increase VEGF expression.
本研究旨在探讨皮瓣移植物后，多区域穿支皮瓣的狭窄血管的血液动力学和形态学变化，并研究低氧和狭窄血管转化过程中 HIF-1α在皮瓣适应中的作用。
建立大鼠背部单蒂多区域穿支皮瓣动物模型，采用氧化胶灌注技术研究皮瓣的血液供应特点。通过 HE 染色和体视显微镜观察血管变化。随后，通过 MTT 法和流式细胞术分别检测缺氧对细胞增殖和凋亡的影响。此外，通过 qRT-PCR 和 Western blot 检测 HIF-1α、iNOS 和 VEGF 在缺氧条件下对 HUVECs 的表达。
结果表明，所有狭窄血管在手术后立即开始扩张。术后第 1 天，部分狭窄血管继续生长扩张，转化为真正的吻合支，而其他血管逐渐萎缩，最终消失。与对照组相比，移植后第 1 天，HIF-1α 和 iNOS 的表达水平均显著升高。唯一不同的是，HIF-1α 随后维持在高水平，iNOS 随后显著降低。更重要的是，VEGF 的表达在术后第 3 天达到最大值，然后下降。在 HUVECs 中，缺氧增加了 HIF-1α、iNOS 和 VEGF 蛋白的表达。此外，它还促进了细胞增殖，抑制了细胞凋亡。此外，我们还发现，缺氧诱导的 VEGF 和 iNOS 上调是由 HIF-1α 过表达介导的，而 HIF-1α 敲除可以逆转缺氧诱导的作用。
我们发现 HIF-1α 可能通过诱导 iNOS 表达促进狭窄血管扩张，通过增加 VEGF 表达促进狭窄血管重建，从而参与跨区域皮瓣的早期血管扩张。
