Chen S S, Yoshihara H, Harada N, Seiyama A, Watanabe M, Kosaka H, Kawano S, Fusamoto H, Kamada T, Shiga T
Department of Physiology, Osaka University Medical School, Japan.
Am J Physiol. 1993 Feb;264(2 Pt 1):G375-82. doi: 10.1152/ajpgi.1993.264.2.G375.
To evaluate the sublobular distribution of oxygen tension, the redox states of mitochondrial cytochrome aa3 were assessed in local regions of the liver lobule by reflectance microspectroscopy. The reflected light from two focused microspots (20 microns in diam) on the surface of the perfused liver, placed on the stage of microscope, was conducted to the spectrophotometer with two separate light guides, giving the reflectance spectra. The redox state of cytochrome aa3 was calculated from the difference in reflectance between 603 and 630 nm. The degree of cytochrome reduction increased with the stepwise decline of the influent or effluent oxygen concentrations. The local oxygen concentration in periportal region for the half-maximal reduction of cytochrome aa3 was higher than that in pericentral region. In addition, the degree of cytochrome aa3 reduction increased with the distance from the periportal region, reflecting a physiological gradient of oxygen tension along the sinusoidal flow, although with an intersinusoidal heterogeneity within liver lobule.
为了评估氧分压的小叶下分布，通过反射显微光谱法在肝小叶的局部区域评估线粒体细胞色素aa3的氧化还原状态。将置于显微镜载物台上的灌注肝脏表面上两个聚焦微点（直径20微米）的反射光，通过两根独立的光导传导至分光光度计，从而获得反射光谱。细胞色素aa3的氧化还原状态由603和630nm处反射率的差异计算得出。细胞色素还原程度随流入或流出氧浓度的逐步降低而增加。细胞色素aa3半最大还原时门周区域的局部氧浓度高于中央周区域。此外，细胞色素aa3的还原程度随距门周区域距离的增加而增加，反映了沿窦状隙血流的氧分压生理梯度，尽管肝小叶内存在窦状隙间异质性。
