Application of hypoxia-induced capillary angiogenesis on regenerative tissue engineering

众所周知，缺氧促进了毛细血管的生成，尽管氧气是维持再生组织生命力所必需的。为了阐明这种不合理的原因，我们试图通过使用我们最初配备的配有摄像机的活体显微镜来可视化活体小鼠模型的微循环，来评估伤口愈合过程中的微循环反应。为了建立不同的氧气环境，背部皮肤室的窗户上覆盖了透氧或不透氧的薄片。比较两组创面完全恢复的进展时间和创面内新生毛细血管总数。组织再生的时间在高氧条件下比低氧条件下更快。高氧组创面完全恢复时间平均为6d，低氧组创面完全恢复时间平均为8d，而低氧组创面新生毛细血管总数明显多于高氧组。这些结果表明，高氧条件有利于创面早期愈合，因为氧气能够从大气中供应给再生组织。另一方面，当再生组织长大到不能通过大气扩散提供氧气时，就需要新生的毛细血管。

It is well known that the hypoxia facilitates capillary angiogenesis, even though the oxygen is necessary to maintain the vital force in regenerative tissues. To clarify such inconsequence we have tried to evaluate the microcirculatory responses during the wound healing process by visualizing the microcirculation in vivo mice models using our original video-camera equipped intravital microscope. In order to establish different oxygen environments, the window of dorsal skinforld chamber was covered with oxygen permeable or oxygen impermeable sheet. The progress time for the complete recovery and the total numbers of new born capillaries in the wound bed were evaluated in comparison with two different oxygen groups. The progress time for the tissue regeneration was faster under high oxygen conditions rather than low oxygen conditions. The complete recovery time in the wound bed under high oxygen and low oxygen groups averaged 6 days and 8 days, respectively, whereas the total numbers of new born capillaries in the wound bed under low oxygen condition were greater than those of high oxygen condition. From these results, it is suggested that high oxygen condition would be advantaged for the wound healing in the early stage since oxygen is able to supply to regenerative tissue from atmosphere. On the other hand, new born capillaries would be required after when the regenerative tissues have grown up to the size larger than oxygen cannot be supplied by diffusion from atmosphere.