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

恶性肿瘤组织氧分压通常较低。这种缺氧状态是由于肿瘤细胞生长和肿瘤循环发展的不平衡。肿瘤组织由体循环提供氧气。怀疑主要氧气供应来自毛细血管的扩散。然而，一部分氧可能来自于从小动脉病变处扩散的氧分子。我们已经开发了显微镜系统，使我们能够确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，并检测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（MMT 060562）。在Balb/c小鼠背侧皮窗上放置氧扩散室，测定微动脉壁氧扩散常数。小肿瘤组将肿瘤植入DSC中，使其生长至2 mm。大肿瘤组将肿瘤植入左臂窝，对照组小动脉壁氧扩散常数为5。3±1。1×10^<-11>[（cm 2/s）（ml O_2. cm-<-3>1组织。mmHg^<-1>）]，而在小肿瘤组中，K为3。9±0。4×10^<-11>[（cm 2/s）（ml O_2. cm-<-3>1组织。在<-1>大肿瘤组中，K为3。1±0。6×10^<-11>[（cm 2/s）（ml O_2. cm-<-3>1组织。mmHg（mmHg<-1>）]。对照组与肿瘤负荷组之间有显著性差异，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量根据肿瘤的大小而增加。微动脉水平氧扩散常数的增加有利于肿瘤细胞的存活和生长。

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.