Pharmahuasca and DMT Rescue ROS Production and Differentially Expressed Genes Observed after Predator and Psychosocial Stress: Relevance to Human PTSD

Post-traumatic stress
disorder (PTSD) is associated with cognitive
deficits, oxidative stress, and inflammation. Animal models have recapitulated
features of PTSD, but no comparative RNA sequencing analysis of differentially
expressed genes (DEGs) in the brain between PTSD and animal models
of traumatic stress has been carried out. We compared DEGs from the
prefrontal cortex (PFC) of an established stress model to DEGs from
the dorsolateral PFC (dlPFC) of humans. We observed a significant
enrichment of rat DEGs in human PTSD and identified 20 overlapping
DEGs, of which 17 (85%) are directionally concordant. N,N-dimethyltryptamine (DMT) is a known indirect
antioxidant, anti-inflammatory, and neuroprotective compound with
antidepressant and plasticity-facilitating effects. We tested the
capacity of DMT, the monoamine oxidase inhibitor (MAOI) harmaline,
and “pharmahuasca” (DMT + harmaline) to reduce reactive
oxygen species (ROS) production and inflammatory gene expression and
to modulate neuroplasticity-related gene expression in the model.
We administered DMT (2 mg/kg IP), harmaline (1.5 mg/kg IP), pharmahuasca,
or vehicle every other day for 5 days, following a 30 day stress regiment.
We measured ROS production in the PFC and hippocampus (HC) by electron
paramagnetic resonance spectroscopy and sequenced total mRNA in the
PFC. We also performed in vitro assays to measure
the affinity and efficacy of DMT and harmaline at 5HT2AR compared to 5-HT. DMT and pharmahuasca reduced ROS production in
the PFC and HC, while harmaline had mixed effects. Treatments normalized
9, 12, and 14 overlapping DEGs, and pathway analysis implicated that
genes were involved in ROS production, inflammation, growth factor
signaling, neurotransmission, and neuroplasticity.

创伤后应激障碍（Post-traumatic stress disorder, PTSD）与认知缺陷、氧化应激及炎症反应密切相关。现有动物模型已成功重现PTSD的核心特征，但目前尚无针对创伤应激状态下PTSD患者与动物模型脑组织内差异表达基因（differentially expressed genes, DEGs）的比较性RNA测序（RNA sequencing）分析。本研究将已建立的应激模型大鼠前额叶皮层（prefrontal cortex, PFC）的差异表达基因，与人类背外侧前额叶皮层（dorsolateral PFC, dlPFC）的差异表达基因进行了对比分析。我们在人类PTSD相关差异表达基因集中发现了大鼠差异表达基因的显著富集，并鉴定出20个重叠的差异表达基因，其中17个（占比85%）的表达调控方向完全一致。

N,N-二甲基色胺（N,N-dimethyltryptamine, DMT）是一类已知的间接抗氧化、抗炎及神经保护化合物，同时具备抗抑郁与促进神经可塑性的生物学效应。本研究测试了DMT、单胺氧化酶抑制剂（monoamine oxidase inhibitor, MAOI）哈马灵（harmaline）以及“医药死藤水”（pharmahuasca，即DMT与哈马灵的联合制剂）在该应激模型中，减少活性氧（reactive oxygen species, ROS）生成、抑制炎症基因表达，并调控神经可塑性相关基因表达的能力。

我们在为期30天的应激造模结束后，每隔一日对大鼠进行腹腔注射：DMT（2 mg/kg）、哈马灵（1.5 mg/kg）、医药死藤水或赋形剂，连续给药5天。通过电子顺磁共振波谱（electron paramagnetic resonance spectroscopy）检测大鼠前额叶皮层与海马体（hippocampus, HC）的活性氧生成水平，并对前额叶皮层的总mRNA进行测序。此外，我们还开展了体外结合实验，以测定DMT与哈马灵相较于5-羟色胺（5-HT）对5-羟色胺2A受体（5HT2AR）的亲和力与激活效能。

实验结果表明：DMT与医药死藤水可显著降低大鼠前额叶皮层与海马体的活性氧生成量，而哈马灵的作用则呈现异质性。三种处理方案分别使9、12、14个重叠差异表达基因的表达水平恢复至正常状态；通路富集分析显示，这些差异表达基因主要参与活性氧生成、炎症反应、生长因子信号传导、神经递质传递及神经可塑性等关键生物学过程。