lntravital microscopic observation of microcirculatory responses under tissue regenerative process

Abstract

It has been reported that the hypoxia facilitates capillary angiogenesis, although the oxygen is essential to regenerate tissues. To clarify such discrepancy, we have tried to observe the microcirculatory responses under low and high ambient oxygen conditions by in vivo mice model. Mice with a dorsal skin chamber were used to observe the microcirculation. The high oxygen condition was carried out to attach the oxygen permeable transparent membrane with chamber, in which tissue oxygen level can be kept around 40 mmHg, the low oxygen condition was performed using oxygen impermeable membrane (<20mmHg). The high oxygen condition facilitated the tissue regeneration, whereas under the low oxygen condition, the capillary angiogenesis was accelerated in the regenerative tissues. From these results it is suggested that the high oxygen condition is effective for the tissue regeneration in the early stage, since oxygen can be supplied to tissues from atmosphere by diffusion. Capillaries would be necessary after when the regenerative tissues grow up larger than the size being unavailable to diffusion.