Neuroscience Program, University of Wyoming, Laramie, WY 82071, USA.
Department of Integrative Physiology and Neuroscience, Washington State University, Vancouver, WA 98686, USA.
Neural Plast. 2018 Apr 23;2018:2108373. doi: 10.1155/2018/2108373. eCollection 2018.
A key factor in the development of obesity is the overconsumption of fatty foods, which, in addition to facilitating weight gain, alters neuronal structures within brain reward circuitry. Our previous work demonstrates that sustained consumption of a high-fat diet (HFD) attenuates spine density in the prefrontal cortex (PFC). Whether HFD promotes structural adaptation among inhibitory cells of the PFC is presently unknown. One structure of interest is the perineuronal net (PNN), a specialized extracellular matrix surrounding, primarily, parvalbumin-containing GABAergic interneurons. PNNs contribute to synaptic stabilization, protect against oxidative stress, regulate the ionic microenvironment within cells, and modulate regional excitatory output. To examine diet-induced changes in PNNs, we maintained rats on one of three dietary conditions for 21 days: ad libitum chow, ad libitum 60% high fat (HF-AL), or limited-access calorically matched high fat (HF-CM), which produced no significant change in weight gain or adiposity with respect to chow controls. The PNN "number" and intensity were then quantified in the prelimbic (PL-PFC), infralimbic (IL-PFC), and ventral orbitofrontal cortex (OFC) using agglutinin (WFA). Our results demonstrated that fat exposure, independent of weight gain, induced a robust decrease in the PNN intensity in the PL-PFC and OFC and a decrease in the PNN number in the OFC.
肥胖发展的一个关键因素是脂肪食物的过度摄入，除了导致体重增加外，还改变了大脑奖励回路中的神经元结构。我们之前的工作表明，持续摄入高脂肪饮食（HFD）会减少前额叶皮层（PFC）中的棘突密度。目前尚不清楚 HFD 是否会促进 PFC 抑制性细胞的结构适应。一个有趣的结构是围绕主要含有脑啡肽的 GABA 能中间神经元的周围神经网（PNN），一种特殊的细胞外基质。PNNs 有助于突触稳定，防止氧化应激，调节细胞内的离子微环境，并调节区域兴奋性输出。为了研究饮食诱导的 PNN 变化，我们让大鼠在三种饮食条件下维持 21 天：随意进食普通食物、随意进食 60%高脂肪食物（HF-AL）或限制进食热量匹配的高脂肪食物（HF-CM），与普通食物对照组相比，HF-CM 对体重增加或肥胖没有显著影响。然后使用凝集素（WFA）在额前皮质（PL-PFC）、下额皮质（IL-PFC）和腹侧眶额皮质（OFC）中定量 PNN“数量”和强度。我们的结果表明，脂肪暴露，与体重增加无关，会导致 PL-PFC 和 OFC 中的 PNN 强度显著降低，OFC 中的 PNN 数量减少。
