Adelaide Medical School, University of Adelaide, Adelaide, South Australia 5005, Australia.
South Australian Health and Medical Research Institute, North Terrace, Adelaide, South Australia 5000, Australia.
J Neurosci. 2018 May 30;38(22):5088-5095. doi: 10.1523/JNEUROSCI.0052-18.2018. Epub 2018 May 14.
Mechanosensitive gastric vagal afferents (GVAs) are involved in the regulation of food intake. GVAs exhibit diurnal rhythmicity in their response to food-related stimuli, allowing time of day-specific satiety signaling. This diurnal rhythmicity is ablated in high-fat-diet (HFD)-induced obesity. Time-restricted feeding (TRF) has a strong influence on peripheral clocks. This study aimed to determine whether diurnal patterns in GVA mechanosensitivity are entrained by TRF. Eight-week-old male C57BL/6 mice ( = 256) were fed a standard laboratory diet (SLD) or HFD for 12 weeks. After 4 weeks of diet acclimatization, the mice were fed either or only during the light phase [Zeitgeber time (ZT) 0-12] or dark phase (ZT12-24) for 8 weeks. A subgroup of mice from all conditions ( = 8/condition) were placed in metabolic cages. After 12 weeks, GVA recordings were taken at 3 h intervals starting at ZT0. HFD mice gained more weight than SLD mice. TRF did not affect weight gain in the SLD mice, but decreased weight gain in the HFD mice regardless of the TRF period. In SLD mice, diurnal rhythms in food intake were inversely associated with diurnal rhythmicity of GVA mechanosensitivity. These diurnal rhythms were entrained by the timing of food intake. In HFD mice, diurnal rhythms in food intake and diurnal rhythmicity of GVA mechanosensitivity were dampened. Loss of diurnal rhythmicity in HFD mice was abrogated by TRF. In conclusion, diurnal rhythmicity in GVA responses to food-related stimuli can be entrained by food intake. TRF prevents the loss of diurnal rhythmicity that occurs in HFD-induced obesity. Diurnal control of food intake is vital for maintaining metabolic health. Diet-induced obesity is associated with strong diurnal changes in food intake. Vagal afferents are involved in regulation of feeding behavior, particularly meal size, and exhibit diurnal fluctuations in mechanosensitivity. These diurnal fluctuations in vagal afferent mechanosensitivity are lost in diet-induced obesity. This study provides evidence that time-restricted feeding entrains diurnal rhythmicity in vagal afferent mechanosensitivity in lean and high-fat-diet (HFD)-induced obese mice and, more importantly, prevents the loss of rhythmicity in HFD-induced obesity. These data have important implications for the development of strategies to treat obesity.
机械敏感性胃迷走传入神经(GVAs)参与食物摄入的调节。GVAs 对与食物相关的刺激的反应表现出昼夜节律性,允许特定的饱腹感信号出现时间。这种昼夜节律性在高脂肪饮食(HFD)诱导的肥胖中被消除。限时进食(TRF)对周围时钟有很强的影响。本研究旨在确定 GVA 机械敏感性的昼夜模式是否受到 TRF 的调节。将 8 周龄雄性 C57BL/6 小鼠(n=256)喂食标准实验室饮食(SLD)或 HFD 12 周。在适应饮食 4 周后,将小鼠分为以下四组进行喂食:或仅在光照阶段(ZT0-12)或黑暗阶段(ZT12-24)进食 8 周。所有条件下的一小部分小鼠(n=8/条件)被放置在代谢笼中。12 周后,从 ZT0 开始每隔 3 小时记录 GVA 记录。HFD 小鼠比 SLD 小鼠体重增加更多。TRF 对 SLD 小鼠的体重增加没有影响,但无论 TRF 时间如何,都能减少 HFD 小鼠的体重增加。在 SLD 小鼠中,食物摄入量的昼夜节律与 GVA 机械敏感性的昼夜节律性呈负相关。这些昼夜节律受到食物摄入时间的调节。在 HFD 小鼠中,食物摄入量的昼夜节律和 GVA 机械敏感性的昼夜节律性减弱。TRF 可防止 HFD 诱导肥胖中出现的昼夜节律性丧失。结论:与食物相关的刺激对 GVA 反应的昼夜节律性可以通过食物摄入来调节。TRF 可防止 HFD 诱导肥胖中出现的昼夜节律性丧失。食物摄入的昼夜控制对于维持代谢健康至关重要。饮食诱导的肥胖与食物摄入的强烈昼夜变化有关。迷走传入神经参与调节进食行为,特别是进食量,并表现出机械敏感性的昼夜波动。这些与饮食诱导肥胖相关的迷走传入神经机械敏感性的昼夜波动会丢失。本研究提供的证据表明,限时进食可使瘦鼠和高脂肪饮食(HFD)诱导肥胖鼠的迷走传入神经机械敏感性的昼夜节律性同步,并更重要的是,防止 HFD 诱导肥胖中昼夜节律性的丧失。这些数据对开发治疗肥胖症的策略具有重要意义。