School of Engineering and Information Technology, Murdoch University , Perth , Western Australia, Australia.
Faculty of Engineering and Mathematical Sciences, The University of Western Australia , Perth , Western Australia, Australia.
Am J Physiol Renal Physiol. 2018 Dec 1;315(6):F1787-F1811. doi: 10.1152/ajprenal.00363.2018. Epub 2018 Sep 26.
The renal medulla is prone to hypoxia. Medullary hypoxia is postulated to be a leading cause of acute kidney injury, so there is considerable interest in predicting the oxygen tension in the medulla. Therefore we have developed a computational model for blood and oxygen transport within a physiologically normal rat renal medulla, using a multilevel modeling approach. For the top-level model we use the theory of porous media and advection-dispersion transport through a realistic three-dimensional representation of the medulla's gross anatomy to describe blood flow and oxygen transport throughout the renal medulla. For the lower-level models, we employ two-dimensional reaction-diffusion models describing the distribution of oxygen through tissue surrounding the vasculature. Steady-state model predictions at the two levels are satisfied simultaneously, through iteration between the levels. The computational model was validated by simulating eight sets of experimental data regarding renal oxygenation in rats (using 4 sets of control groups and 4 sets of treatment groups, described in 4 independent publications). Predicted medullary tissue oxygen tension or microvascular oxygen tension for control groups and for treatment groups that underwent moderate perturbation in hemodynamic and renal functions is within ±2 SE values observed experimentally. Diffusive shunting between descending and ascending vasa recta is predicted to be only 3% of the oxygen delivered. The validation tests confirm that the computational model is robust and capable of capturing the behavior of renal medullary oxygenation in both normal and early-stage pathological states in the rat.
肾髓质容易缺氧。髓质缺氧被认为是急性肾损伤的主要原因，因此人们非常关注预测髓质中的氧分压。因此，我们使用多尺度建模方法为生理正常的大鼠肾髓质内的血液和氧气传输开发了一个计算模型。对于顶级模型，我们使用多孔介质理论和通过对髓质大体解剖的真实三维表示的对流 - 弥散传输来描述整个肾髓质中的血流和氧气传输。对于较低层次的模型，我们采用二维反应 - 扩散模型来描述血管周围组织中的氧气分布。通过在层次之间迭代，同时满足两个层次的稳态模型预测。该计算模型通过模拟大鼠肾氧合的八组实验数据进行了验证（使用四组对照组和四组治疗组，在四个独立的出版物中进行了描述）。对照组和接受中度血液动力学和肾功能干扰的治疗组的预测髓质组织氧张力或微血管氧张力在实验观察到的±2 SE 值内。预测下行和上行直小血管之间的弥散分流仅占输送氧气的 3%。验证测试证实，该计算模型稳健且能够捕捉大鼠正常和早期病理状态下肾髓质氧合的行为。
