Hypothermia at 35 A°C Reduces the Time-Dependent Microglial Production of Pro-inflammatory and Anti-inflammatory Factors that Mediate Neuronal Cell Death
Hypothermia at 35 A°C Reduces the Time-Dependent Microglial Production of Pro-inflammatory and Anti-inflammatory Factors that Mediate Neuronal Cell Death
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DOI：
10.1007/s12028-013-9911-5
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发表时间：
2014-04-01
影响因子：
3.5
通讯作者：
Suenaga, Hiromi
中科院分区：
文献类型：
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作者：
Matsui, Tomohiro;Yoshida, Yusuke;Suenaga, Hiromi
治疗性低温可以保护严重脑损伤后的神经元。这种效果主要是在32-34摄氏度的核心温度下实现的；然而，治疗性低温的最佳温度尚未完全确定。在这里，我们研究了35℃低温培养对刺激激活的小胶质细胞肿瘤坏死因子(TNF)- α、白细胞介素(IL)-10和一氧化氮（NO）的时间依赖性表达的降低是否与我们之前的报道中确定的33℃低温培养具有相同的影响，以及这些因素是否直接诱导神经元细胞死亡。我们测定了用三磷酸腺苷（ATP）、toll样受体（TLR）2激动剂(n -棕榈酰-S-（2,3-二（棕榈酰氧基）-(2R，S)-丙基）-(R)-半胱氨酸-丝氨酸-（赖氨酸）3-赖氨酸、Pam（3)CSK(4)）或TLR4激动剂（脂多糖）培养的小胶质细胞在轻度低温（33℃）、极低温（35℃）和常温（37℃）条件下产生的细胞因子和NO的水平。我们还测定了重组tnf - α或IL-10或(+/-)-(E)-4-乙基-2-[(E)-羟亚胺]-5-硝基-3-己胺（NOR3， NO供体）处理大鼠神经元嗜铬细胞瘤PC12细胞的活力。与常温相比，在1.5-6小时和24-48小时，低低温分别降低了tnf - α的产生，以及IL-10和NO的产生，尽管与轻度低温相比，一些影响有所减弱。在35℃低温培养24小时后，暴露于tnf - α、IL-10和NOR3以浓度依赖的方式导致PC12细胞死亡，在33℃低温培养时观察到，ATP和tlr激活的小胶质细胞早期tnf - α和晚期IL-10和NO的产生减少，尽管影响减弱。此外，这些因素引起神经元细胞的死亡呈浓度依赖性。这些结果表明，治疗性低温降低小胶质细胞产生tnf - α、IL-10和NO，导致神经元细胞死亡受到抑制。35摄氏度的低温可能足以引起神经保护作用。
Therapeutic hypothermia protects neurons after severe brain damage. This effect has been mainly achieved at the core temperatures of 32-34 A degrees C; however, the optimum temperature of therapeutic hypothermia is not fully defined. Here we studied whether hypothermic culture at 35 A degrees C had the same effects on the decrease of time-dependent expression of tumor necrosis factor (TNF)-alpha, interleukin (IL)-10, and nitric oxide (NO) by stimuli-activated microglia as that at 33 A degrees C, as determined in our previous reports, and whether these factors directly induced neuronal cell death.We determined the levels of cytokines and NO produced by microglia cultured with adenosine triphosphate (ATP), a toll-like receptor (TLR)2 agonist (N-palmitoyl-S-(2,3-bis(palmitoyloxy)-(2R,S)-propyl)-(R)-cysteinyl-seryl-(lysyl)3-lysine, Pam(3)CSK(4)), or a TLR4 agonist (lipopolysaccharide) under mild hypothermic (33 A degrees C), minimal hypothermic (35 A degrees C), and normothermic (37 A degrees C) conditions. We also determined the viability of rat neuronal pheochromocytoma PC12 cells treated with recombinant TNF-alpha or IL-10 or (+/-)-(E)-4-ethyl-2-[(E)-hydroxyimino]-5-nitro-3-hexenamide (NOR3, an NO donor).Production of TNF-alpha, as well as that of IL-10 and NO were decreased by minimal hypothermia at 1.5-6, and 24-48 h, respectively, compared with normothermia, although some effects were diminished as compared with those by mild hypothermia. Exposure to TNF-alpha, IL-10, and NOR3 caused the death of PC12 cells in a concentration-dependent manner after 24 h.Hypothermic culture at 35 A degrees C decreased the production of early-phase TNF-alpha and late-phase IL-10 and NO from ATP- and TLR-activated microglia as observed at 33 A degrees C, albeit with diminished effects. Moreover, these factors caused the death of neuronal cells in a concentration-dependent manner. These results suggest that the attenuation of microglial production of TNF-alpha, IL-10, and NO by therapeutic hypothermia leads to the inhibition of neuronal cell death. Minimal hypothermia at 35 A degrees C may be sufficient to elicit neuroprotective effect.