Department of Pediatrics, Faculty of Medicine, University of Yamanashi, Yamanashi, Japan.
Clinical Research Center, Murayama Medical Center, Tokyo, Japan.
J Physiol Sci. 2022 Oct 13;72(1):26. doi: 10.1186/s12576-022-00848-y.
Microglia modulate cardiorespiratory activities during chronic hypoxia. It has not been clarified whether microglia are involved in the cardiorespiratory responses to acute hypoxia. Here we investigated this issue by comparing cardiorespiratory responses to two levels of acute hypoxia (13% O for 4 min and 7% O for 5 min) in conscious unrestrained rats before and after systemic injection of minocycline (MINO), an inhibitor of microglia activation. MINO increased blood pressure but not lung ventilation in the control normoxic condition. Acute hypoxia stimulated cardiorespiratory responses in MINO-untreated rats. MINO failed to significantly affect the magnitude of hypoxia-induced blood pressure elevation. In contrast, MINO tended to suppress the ventilatory responses to hypoxia. We conclude that microglia differentially affect cardiorespiratory regulation depending on the level of blood oxygenation. Microglia suppressively contribute to blood pressure regulation in normoxia but help maintain ventilatory augmentation in hypoxia, which underscores the dichotomy of central regulatory pathways for both systems.
小胶质细胞调节慢性低氧时的心肺活动。但小胶质细胞是否参与急性低氧的心肺反应尚不清楚。因此，我们通过比较系统注射小胶质细胞激活抑制剂米诺环素（MINO）前后清醒自由活动大鼠对两种水平急性低氧（13% O 4 分钟和 7% O 5 分钟）的心肺反应来研究这个问题。MINO 在正常氧合条件下增加血压但不增加肺通气。急性低氧刺激 MINO 未处理大鼠的心肺反应。MINO 未能显著影响缺氧引起的血压升高幅度。相反，MINO 倾向于抑制低氧引起的通气反应。因此，我们得出结论，小胶质细胞根据血氧水平的不同，对心肺调节产生不同的影响。在正常氧合时，小胶质细胞抑制性地参与血压调节，但有助于维持低氧时的通气增强，这突出了这两个系统的中枢调节途径的二分法。
