Analysis of oxygen transport to malignant tumor and mechanism of enhancing effect of treatment by oxygenation of tumor tissue

通常，恶性肿瘤组织氧张力较低。这种缺氧状态是由于肿瘤细胞生长和肿瘤循环发育不平衡所致。肿瘤组织由体循环供氧。主要供氧被怀疑是由毛细血管扩散而来。然而，部分氧气可能来源于小动脉病变处弥散的氧分子。我们开发了一种显微镜系统，使我们能够测定小动脉壁的氧扩散常数。我们将该系统应用于肿瘤负荷动物，检测了皮下小动脉壁的氧扩散常数。我们使用Balb/c小鼠和小鼠哺乳动物肿瘤（MMT060562）。为了测定小动脉壁氧扩散常数，我们在Balb/c小鼠身上放置背侧皮肤窗腔。小肿瘤组将肿瘤植入DSC，任其生长至2mm。大肿瘤组在左腋窝植入肿瘤。对照组小动脉壁氧扩散常数为5。3±1。1×10^<-11> [(cm2/s)(ml O_2。厘米^ < 3 >组织。mmHg^<-1>)]，而小肿瘤组K = 3。9±0。4×10^<-11> [(cm2/s)(ml O_2。厘米^ < 3 >组织。mmHg^<-1>)]，大肿瘤组K = 3。1±0。6×10^<-11> [(cm2/s)(ml O_2。厘米^ < 3 >组织。毫米汞柱^ < 1 >)。对照组与肿瘤负荷组之间存在显著性差异。这一现象表明，在肿瘤负荷动物中，通过小动脉病变的氧分子数量随着肿瘤的大小而增加。微动脉周围氧扩散常数的增加似乎有利于肿瘤细胞的生存和生长。

Usually, tissue oxygen tension is low in malignant tumor. This hypoxic state is due to the imbalance of tumor cell growth and development of tumor circulation. Tumor tissue is supplied oxygen from systemic circulation. Main oxygen supply is suspected to be derived from capillary by diffusion. However, some part of oxygen might be derived from the oxygen molecule diffused from arteriolar lesion.We have developed the microscope system that enabled us to determine the oxygen diffusion constant of arteriolar wall. We have applied this system to tumor burden animals and examine the oxygen diffusion constant of the subcutaneous arteriolar wall.We used Balb/c mouse and mouse mammalian tumor(MMT060562). To measure the oxygen diffusion constant of the arteriolar wall, we placed Dorsal Skin Window Chamber on Balb/c mouse. In small tumor group, tumor was implanted in the DSC and let it grow to 2mm. In large tumor group, tumor was implanted at the left arm pit.Oxygen diffusion constant of arteriolar wall in control group was 5. 3±1. 1×10^<-11> [(cm2/s)(ml O_2. cm^<-3> tissue. mmHg^<-1>)], while in the small tumor group, K was 3. 9±0. 4×10^<-11> [(cm2/s)(ml O_2. cm^<-3> tissue. mmHg^<-1>)] and in the large tumor group K was 3. 1±0. 6×10^<-11> [(cm2/s)(ml O_2. cm^<-3> tissue. mmHg^<-1>)]. There are significant difference between control group and tumor burden groups.This phenomenon indicated that in tumor burden animals, the amount of oxygen molecules that pass through the arteriolar lesion increases according to the size of tumor. The increase of oxygen diffusion constant around arteriole level seems beneficial for the tumor cells in regards to the survival and growth of malignant tumor.