The 3rd Xiangya Hospital, Central South University, Department of Critical Care Medicine and Hematology, Changsha, Hunan, China.
Department of Intensive Care Unit & Infection Prevention and Control, The Second People's Hospital of Shenzhen, Shenzhen, Guangdong, China.
PeerJ. 2022 Aug 4;10:e13799. doi: 10.7717/peerj.13799. eCollection 2022.
Thrombocytopenia, an early common complication in heatstroke (HS), has been widely considered as a mortality predictor of HS. The mechanism underlying thrombocytopenia in HS remains unknown. It is not known whether NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome is activated in HS platelet, which, in turn, induces platelet activation and thrombocytopenia. This study tried to clarify the activation of the NOD-like receptor signaling pathway under HS conditions and investigate its roles in mediating HS-induced thrombocytopenia.
Rat HS models were established in a certain ambient temperature and humidity. Platelets, isolated from blood, were counted and CD62P, an index of platelet activation, was measured by flow cytometry in all rats. The colocalization of NLRP3 inflammasome in platelet was detected by confocal fluorescence microscopy. Mitochondrial-derived reactive oxygen species (ROS) was detected using the molecular probes. Plasma HMGB1 and IL-1β levels were measured by ELISA.
Platelet activation, showed by upregulated CD62P, and thrombocytopenia were observed in HS rats. HS activated the NLRP3 inflammasome, which was induced by elevated levels of ROS, while the upregulated CD62P and thrombocytopenia triggered by NLRP3 inflammasome were attributed to the high mobility group box protein 1 (HMGB1) inplasma. Moreover, inhibition of the NOD-like receptor signaling pathway in rats with HS suppressed platelet activation and the decline of platelet count. Similar results were obtained when the receptor toll-like receptor 4 (TLR4)/advanced glycation end product (RAGE) was blocked.
The NOD-like receptor signaling pathway induces platelet activation and thrombocytopenia in HS rats. These findings suggested that the NLRP3 inflammasome might be the potential target for HS treatment.
血小板减少症是中暑（HS）早期常见的并发症，被广泛认为是 HS 死亡率的预测因子。HS 中血小板减少症的机制尚不清楚。目前尚不清楚 NOD 样受体家族含pyrin 结构域蛋白 3（NLRP3）炎症小体是否在 HS 血小板中被激活，进而诱导血小板活化和血小板减少症。本研究试图阐明 HS 条件下 NOD 样受体信号通路的激活，并探讨其在介导 HS 诱导的血小板减少症中的作用。
在一定的环境温度和湿度下建立大鼠 HS 模型。通过流式细胞术计数所有大鼠血液分离的血小板，并测量血小板活化的指标 CD62P。通过共聚焦荧光显微镜检测血小板中 NLRP3 炎症小体的共定位。使用分子探针检测线粒体衍生的活性氧（ROS）。通过 ELISA 测定血浆高迁移率族蛋白 B1（HMGB1）和白细胞介素 1β（IL-1β）水平。
HS 大鼠出现血小板活化，表现为 CD62P 上调，血小板减少。HS 激活了 NLRP3 炎症小体，这是由 ROS 水平升高引起的，而 NLRP3 炎症小体引起的 CD62P 上调和血小板减少归因于血浆中的高迁移率族蛋白 B1（HMGB1）。此外，在 HS 大鼠中抑制 NOD 样受体信号通路抑制了血小板活化和血小板计数下降。当阻断受体 Toll 样受体 4（TLR4）/晚期糖基化终产物（RAGE）时，也得到了类似的结果。
NOD 样受体信号通路在 HS 大鼠中诱导血小板活化和血小板减少症。这些发现表明，NLRP3 炎症小体可能是 HS 治疗的潜在靶点。
