Evidence for role of capillaries in regulation of skeletal muscle oxygen supply
Evidence for role of capillaries in regulation of skeletal muscle oxygen supply
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DOI：
10.1111/micc.12699
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发表时间：
2021-05-07
期刊：
影响因子：
2.4
通讯作者：
Ellis，Christopher G.
中科院分区：
文献类型：
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作者：
Ghonaim，Nour W.;Fraser，Graham M.;Ellis，Christopher G.
如何调节毛细血管的氧气 (O2) 供应以满足组织的需求尚不清楚。红细胞被提议作为这种调节机制中的传感器，因为它们以氧饱和度 (SO2) 依赖的方式释放 ATP（一种血管舒张剂）。 ATP 引起内皮细胞超极化，导致小动脉血管舒张。目的我们提出，单个毛细血管单位可以通过电耦合内皮直接与上游小动脉通讯来调节自己的 O2 供应。方法为了验证这一假设，我们开发了一种透明的微交换装置，用于与完整组织的表面毛细血管进行局部 O2 交换。该装置采用 0.2 × 1.0 mm 的透氧微出口制成。使用双波长视频显微镜对大鼠趾长伸肌 (EDL) 进行实验，测量毛细血管血流动力学和红细胞 SO2。仅使用位于微出口上方的毛细血管来测量对局部 O2 扰动的响应。结果气体混合物 %O2 的阶跃变化引起红细胞 SO2 的生理变化，如果至少刺激 3-4 个毛细血管，流量的适当变化可以抵消 O2 挑战。结论这些结果支持我们的假设，即各个毛细管单位在调节其红细胞供应以响应不断变化的 O2 环境方面发挥作用。
How oxygen (O2) supply to capillaries is regulated to match the tissue's demand is unknown. Erythrocytes have been proposed as sensors in this regulatory mechanism since they release ATP, a vasodilator, in an oxygen saturation (SO2)‐dependent manner. ATP causes hyperpolarization of endothelial cells resulting in conducted vasodilation to arterioles.ObjectiveWe propose individual capillary units can regulate their own O2supply by direct communication to upstream arterioles via electrically coupled endothelium.MethodsTo test this hypothesis, we developed a transparent micro‐exchange device for localized O2exchange with surface capillaries of intact tissue. The device was fabricated with an O2permeable micro‐outlet 0.2 × 1.0 mm. Experiments were performed on rat extensor digitorum longus (EDL) muscle using dual wavelength video microscopy to measure capillary hemodynamics and erythrocyte SO2. Responses to local O2perturbations were measured with only capillaries positioned over the micro‐outlet.ResultsStep changes in the gas mixture %O2caused physiological changes in erythrocyte SO2, and appropriate changes in flow to offset the O2challenge if at least 3–4 capillaries were stimulated.ConclusionThese results support our hypothesis that individual capillary units play a role in regulating their erythrocyte supply in response to a changing O2environment.