维生素C对慢性束缚应激雌鼠焦虑抑郁行为的影响及机制

The Effect of Vitamin C on Anxiodepression-like Behaviors in Female Mice Subjected to Chronic Restraint Stress and Its Mechanisms

关键词:  维生素C  焦虑症  抑郁症  脑源性神经营养因子  全基因组甲基化

Key words:  vitamin C  anxiety  depression  BDNF  genome methylation

摘要:

目的 研究维生素C对慢性束缚应激 (Chronic restraint stress，CRS) 诱导的雌性小鼠焦虑-抑郁样行为的作用及机制。方法 通过强迫游泳试验筛选不同剂量维生素C对雌性小鼠的抗抑郁样作用，选择最佳剂量进一步评估其对CRS雌性小鼠焦虑-抑郁模型的影响。将雌性小鼠分对照组和CRS处理组，对照组正常饲养2周，CRS处理组给予每天束缚应激处理2周，通过糖水偏好实验筛选具有抑郁样表型的实验动物，进一步分为CRS模型组和CRS+维生素C组，24小时后观察其对小鼠焦虑和抑郁样行为的作用。结合全基因组甲基化测序、甲基化差异性分析和Western Blotting技术，探索维生素C的作用机制。结果 CRS处理后多数小鼠表现出焦虑-抑郁样行为，包括：进入高架十字迷宫开放臂时间和次数减少（P < 0.01），旷场中心区时间（P < 0.05）和距离（P < 0.01）减少，悬尾和强迫游泳不动时间显著增加（P < 0.01），糖水偏好率下降（P < 0.001）。与CRS模型组相比，CRS+维生素C组小鼠糖水偏好率（P < 0.01）升高，悬尾和强迫游泳不动时间（P < 0.01）减少，进入高架十字迷宫开放臂时间（P < 0.01）、次数增加（P < 0.05），旷场中心区时间、距离增加（P < 0.05）。维生素C可逆转CRS引起的内侧前额皮层脑区脑源性神经营养因子表达和下游Akt信号通路活性下降。全基因组甲基化酶转法测序分析发现，与CRS模型组相比，CRS+维生素C组共检测到13820个甲基化差异区域，脑源性神经营养因子信号通路的关键下游分子——核糖体S6蛋白激酶β2等共7708个基因甲基化水平下调，提示维生素C可能通过降低DNA甲基化、上调相关基因转录活性，易化脑源性神经营养因子信号通路活化。结论 维生素C逆转CRS诱导的雌性小鼠焦虑-抑郁样行为，其机制可能和促进前额皮层脑区脑源性神经营养因子信号通路恢复有关。

Abstract:

OBJECTIVE To investigate the effect and mechanism of vitamin C on anxiety- and depression-like behaviors induced by chronic restraint stress (CRS) in female mice. METHODS Through the forced swim test, we screened the antidepressant activity of different doses of vitamin C in female mice to select the optimal dose and further evaluated its effects on anxiety- and depression-like behaviors in CRS-exposed female mice. Female mice were divided into a control group and a CRS treatment group. The control group was housed normally for 2 weeks, while the CRS treatment group received daily restraint stress for 2 weeks. Depressive-like behavior was assessed using the sucrose preference test, and female mice exhibiting depressive behavioral phenotypes were further divided into a CRS model group and a CRS + vitamin C group. Behavioral effects on anxiety and depression were observed 24 hours after the injection. Whole-genome methylation sequencing, differential methylation analysis techniques and Western Blotting were employed to elucidate the mechanism underlying the antidepressant effects of vitamin C. RESULTS After CRS treatment, most mice exhibited anxiodepression-like behaviors, including significantly reduced time spent and entries into the open arms of the elevated plus maze (P < 0.01), reduced time (P < 0.05) and distance traveled (P < 0.01) in the central area of the open field test, significantly increased immobility time in the tail suspension test and forced swim test (P < 0.01), and a decline in sucrose preference rate (P < 0.001). Compared with the CRS model group, the CRS + vitamin C group showed an increased sucrose preference rate (P < 0.01), reduced immobility time in the tail suspension test and forced swim test (P < 0.01), increased time spent (P < 0.01) and entries (P < 0.05) into the open arms of the elevated plus maze, and increased time spent and distance traveled in the central area of the open field test (P < 0.05). Vitamin C reversed the CRS-induced decrease in the expression of brain-derived neurotrophic factor in the medial prefrontal cortex and the downregulation of downstream Akt signaling pathway activity. Whole-genome methylation sequencing revealed that, compared with the CRS model group, the CRS + vitamin C group exhibited 13,820 significantly differentially methylated regions and a decrease in the methylation levels of 7,708 genes, including the key downstream signaling molecule of brain-derived neurotrophic factor, ribosomal S6 protein kinase β2, suggests that vitamin C may facilitate the activation of the brain-derived neurotrophic factor signaling pathway by reducing DNA methylation levels and upregulating the transcriptional activity of related genes. CONCLUSION Vitamin C reversed CRS-induced anxiety- and depression-like behaviors in female mice, potentially through restoration of BDNF signaling in the medial prefrontal cortex.