Abstract：
OBJECTIVE: To investigate cellular changes in protein expression in the trigeminal ganglion in an established preclinical chronic model of temporomandibular joint disorder (TMD) in response to grape seed extract (GSE) supplementation based on its beneficial use in preclinical chronic orofacial pain models.
METHODS: Three experimental conditions included female Sprague-Dawley rats as naïve controls, and animals subjected to neck muscle inflammation and prolonged jaw opening with and without daily supplementation of GSE in the drinking water prior to inflammation. Changes were evaluated in mechanical sensitivity to von Frey filaments and protein expression in the trigeminal ganglion of animals 14 days post jaw opening.
RESULTS: Calcitonin-gene related peptide and protein kinase A, proteins positively associated with peripheral sensitization and enhanced nociception, did not show elevated expression at day 14 in the model compared to naïve or GSE supplemented animals. However, neuronal levels of glutamate decarboxylase (GAD) 65/67, which are enzymes responsible for the synthesis of the inhibitory neurotransmitter GABA that functions to suppress neuronal excitability, were significantly decreased on day 14 post jaw opening. Similarly, a significant decrease in neuronal expression of the GABA receptor subunits GABAB1 and GABAB2, but not GABAA, was observed in the TMD model. Importantly, GSE prevented suppression of GAD 65/67 and GABAB subunits, maintaining levels similar to naïve animals.
CONCLUSIONS: Results from our study provide evidence of the downregulation of inhibitory GABAergic proteins in trigeminal ganglion neurons in a preclinical chronic TMD model and the benefits of GSE supplementation in preventing their suppression and maintaining normal levels.
METHODS: Three experimental conditions included female Sprague-Dawley rats as naïve controls, and animals subjected to neck muscle inflammation and prolonged jaw opening with and without daily supplementation of GSE in the drinking water prior to inflammation. Changes were evaluated in mechanical sensitivity to von Frey filaments and protein expression in the trigeminal ganglion of animals 14 days post jaw opening.
RESULTS: Calcitonin-gene related peptide and protein kinase A, proteins positively associated with peripheral sensitization and enhanced nociception, did not show elevated expression at day 14 in the model compared to naïve or GSE supplemented animals. However, neuronal levels of glutamate decarboxylase (GAD) 65/67, which are enzymes responsible for the synthesis of the inhibitory neurotransmitter GABA that functions to suppress neuronal excitability, were significantly decreased on day 14 post jaw opening. Similarly, a significant decrease in neuronal expression of the GABA receptor subunits GABAB1 and GABAB2, but not GABAA, was observed in the TMD model. Importantly, GSE prevented suppression of GAD 65/67 and GABAB subunits, maintaining levels similar to naïve animals.
CONCLUSIONS: Results from our study provide evidence of the downregulation of inhibitory GABAergic proteins in trigeminal ganglion neurons in a preclinical chronic TMD model and the benefits of GSE supplementation in preventing their suppression and maintaining normal levels.
摘要：
目的：根据葡萄籽提取物（GSE）在临床前慢性口面疼痛模型中的有益用途，研究已建立的颞下颌关节紊乱病（TMD）临床前慢性模型中三叉神经节蛋白表达的细胞变化。
方法：三种实验条件包括雌性Sprague-Dawley大鼠作为原始对照，和动物遭受颈部肌肉炎症和长时间的下颌张开，在炎症前每天补充和不补充饮用水中的GSE。下颌张开后14天，评估了动物对vonFrey丝的机械敏感性和三叉神经节中蛋白质表达的变化。
结果：降钙素基因相关肽和蛋白激酶A，与外周致敏和增强的伤害感受呈正相关的蛋白质，与未经治疗或补充GSE的动物相比，该模型在第14天未显示出升高的表达。然而,谷氨酸脱羧酶（GAD）65/67，这是负责抑制神经元兴奋性的抑制性神经递质GABA合成的酶，在开颌后第14天显著降低。同样，GABA受体亚基GABAB1和GABAB2的神经元表达显着降低，而不是GABAA，在TMD模型中观察到。重要的是,GSE阻止GAD65/67和GABAB亚基的抑制，保持类似于幼稚动物的水平。
结论：我们的研究结果提供了在临床前慢性TMD模型中三叉神经节神经元抑制性GABA能蛋白下调的证据，以及补充GSE在防止其抑制和维持正常水平方面的益处。
方法：三种实验条件包括雌性Sprague-Dawley大鼠作为原始对照，和动物遭受颈部肌肉炎症和长时间的下颌张开，在炎症前每天补充和不补充饮用水中的GSE。下颌张开后14天，评估了动物对vonFrey丝的机械敏感性和三叉神经节中蛋白质表达的变化。
结果：降钙素基因相关肽和蛋白激酶A，与外周致敏和增强的伤害感受呈正相关的蛋白质，与未经治疗或补充GSE的动物相比，该模型在第14天未显示出升高的表达。然而,谷氨酸脱羧酶（GAD）65/67，这是负责抑制神经元兴奋性的抑制性神经递质GABA合成的酶，在开颌后第14天显著降低。同样，GABA受体亚基GABAB1和GABAB2的神经元表达显着降低，而不是GABAA，在TMD模型中观察到。重要的是,GSE阻止GAD65/67和GABAB亚基的抑制，保持类似于幼稚动物的水平。
结论：我们的研究结果提供了在临床前慢性TMD模型中三叉神经节神经元抑制性GABA能蛋白下调的证据，以及补充GSE在防止其抑制和维持正常水平方面的益处。
