Department of Pharmacology and Toxicology, Institute of Pharmacy and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80-82/III, A-6020 Innsbruck, Austria.
Cellular Neurocience, Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany.
Int J Mol Sci. 2022 Oct 27;23(21):13052. doi: 10.3390/ijms232113052.
Neuroinflammation is discussed to play a role in specific subgroups of different psychiatric disorders, including anxiety disorders. We have previously shown that a mouse model of trait anxiety (HAB) displays enhanced microglial density and phagocytic activity in key regions of anxiety circuits compared to normal-anxiety controls (NAB). Using minocycline, we provided causal evidence that reducing microglial activation within the dentate gyrus (DG) attenuated enhanced anxiety in HABs. Besides pharmacological intervention, "positive environmental stimuli", which have the advantage of exerting no side-effects, have been shown to modulate inflammation-related markers in human beings. Therefore, we now investigated whether environmental enrichment (EE) would be sufficient to modulate upregulated neuroinflammation in high-anxiety HABs. We show for the first time that EE can indeed attenuate enhanced trait anxiety, even when presented as late as adulthood. We further found that EE-induced anxiolysis was associated with the attenuation of enhanced microglial density (using Iba-1 as the marker) in the DG and medial prefrontal cortex. Additionally, EE reduced Iba1 + CD68+ microglia density within the anterior DG. Hence, the successful attenuation of trait anxiety by EE was associated in part with the normalization of neuro-inflammatory imbalances. These results suggest that pharmacological and/or positive behavioral therapies triggering microglia-targeted anti-inflammatory effects could be promising as novel alternatives or complimentary anxiolytic therapeutic approaches in specific subgroups of individuals predisposed to trait anxiety.
神经炎症被认为在不同精神障碍的特定亚组中发挥作用,包括焦虑障碍。我们之前已经表明,特质焦虑的小鼠模型(HAB)在焦虑回路的关键区域显示出比正常焦虑对照(NAB)更高的小胶质细胞密度和吞噬活性。使用米诺环素,我们提供了因果证据,表明减少齿状回(DG)中的小胶质细胞激活可以减轻 HAB 中的增强焦虑。除了药物干预外,“积极的环境刺激”具有无副作用的优势,已被证明可以调节人类与炎症相关的标志物。因此,我们现在研究了环境丰富(EE)是否足以调节高焦虑 HAB 中上调的神经炎症。我们首次表明,EE 确实可以减轻增强的特质焦虑,即使在成年后出现也可以。我们进一步发现,EE 诱导的焦虑缓解与 DG 和内侧前额叶皮层中增强的小胶质细胞密度(以 Iba-1 作为标志物)的衰减有关。此外,EE 减少了 DG 前区的 Iba1 + CD68 +小胶质细胞密度。因此,EE 通过部分减轻特质焦虑,与神经炎症失衡的正常化有关。这些结果表明,触发小胶质细胞靶向抗炎作用的药理学和/或积极行为疗法可能是具有特质焦虑倾向的个体的新型替代或补充抗焦虑治疗方法。