Natale Nick R, Kent Molly, Fox Nathan, Vavra Dylan, Lambert Kelly
Dept of Psychology, University of Richmond, VA 23173, USA.
Dept of Biology, Virginia Military Institute, Lexington, VA 24450, USA.
IBRO Neurosci Rep. 2021 Nov 6;11:207-215. doi: 10.1016/j.ibneur.2021.10.004. eCollection 2021 Dec.
Probiotics that regulate the microbiome-gut-brain axis and provide mental health benefits to the host are referred to as psychobiotics. Preclinical studies have demonstrated psychobiotic effects on early life stress-induced anxiety- and depression-related behavior in rodents; however, the specific mechanisms remain ill-defined. In the current study, we investigated the effects of probiotic supplementation on neurobiological responses to chronic stress in adult male Long-Evans rats. Twenty-four rats were randomly assigned to probiotic (PB) or vehicle control (VEH) groups, then to either chronic unpredictable stress (CUS) or no-stress control (CON) conditions within each group (n = 6/subgroup). We hypothesized that PB supplementation would reduce markers of anxiety and enhance emotional resilience, especially in the CUS animals. In the cognitive uncertainty task, a nonsignificant trend was observed indicating that the PB-supplemented animals spent more time oriented toward the food reward than VEH animals. In the open-field task, CUS-PB animals spent more time in the center of the arena than CUS-VEH animals, an effect not observed between the two CON groups. In the swim task, the PB animals, regardless of stress assignment, exhibited increased floating, suggesting a conserved response in a challenging context. Focusing on the endocrine measures, higher dehydroepiandrosterone (DHEA)-to-corticosterone fecal metabolite ratios, a correlate of emotional resilience, were observed in PB animals. Further, PB animals exhibited reduced microglia immunoreactivity in the basolateral amygdala, possibly indicating a neuroprotective effect of PB supplements in this rodent model. These results provide evidence that PB supplementation interacts with stress exposure to influence adaptive responses associated with endocrine, neural, and behavioral indices of anxiety.
调节微生物群-肠-脑轴并为宿主提供心理健康益处的益生菌被称为精神益生菌。临床前研究已证明精神益生菌对啮齿动物早期生活应激诱导的焦虑和抑郁相关行为有影响；然而，具体机制仍不明确。在当前研究中，我们调查了补充益生菌对成年雄性长 Evans 大鼠慢性应激神经生物学反应的影响。24 只大鼠被随机分为益生菌（PB）组或载体对照组（VEH），然后在每组内分为慢性不可预测应激（CUS）组或无应激对照组（CON）（每组 n = 6/亚组）。我们假设补充 PB 会降低焦虑指标并增强情绪恢复力，尤其是在 CUS 动物中。在认知不确定性任务中，观察到一个无显著意义的趋势，表明补充 PB 的动物比 VEH 动物花费更多时间朝向食物奖励。在旷场任务中，CUS-PB 动物比 CUS-VEH 动物在场地中心花费更多时间，而在两个 CON 组之间未观察到这种效应。在游泳任务中，无论应激分配如何，PB 组动物漂浮增加，表明在具有挑战性的环境中有保守反应。关注内分泌指标，在 PB 组动物中观察到较高的脱氢表雄酮（DHEA）与皮质酮粪便代谢物比率，这与情绪恢复力相关。此外，PB 组动物在基底外侧杏仁核中的小胶质细胞免疫反应性降低，这可能表明在该啮齿动物模型中 PB 补充剂具有神经保护作用。这些结果提供了证据，表明补充 PB 与应激暴露相互作用，以影响与焦虑的内分泌、神经和行为指标相关的适应性反应。
