Byrd K E, Sukay M J, Swartz D R
Department of Anatomy, Indiana University School of Medicine, Indianapolis 46202-5120, USA.
Arch Oral Biol. 1998 Sep;43(9):711-6. doi: 10.1016/s0003-9969(98)00045-4.
Earlier work has shown that two important consequences of implanting thyrotropin-releasing hormone (TRH) microspheres near motoneurones within the trigeminal motor nucleus of actively growing rats are increased muscle mass and a darkening of the implant-side masticatory muscles. These phenomena have been associated with altered neuromuscular activity patterns and biomechanical forces that directly influence craniofacial growth and development. Now, whether the implantation of TRH microspheres in proximity to trigeminal motoneurones would affect the oxidative capacity of the implant-side masseter muscles was investigated. Cytochrome C oxidase (COX) assays were carried out for both implant- and non-implant-side masseters of TRH (n = 5) and blank microsphere (n = 6) Sprague-Dawley rats after stereotactic surgery at 35 days of age. Analyses of both groups at 14 days post-implantation revealed that the COX activity levels of implant-side masseters in TRH-implanted rats was significantly (P< or =0.05) greater than that of non-implant-side masseters; rats implanted with blank microsphere exhibited no significant difference between implant- and non-implant-side masseter COX activity levels. The stated null hypothesis was therefore rejected. These data suggest that TRH implants in proximity to trigeminal motoneurones effect increased oxidative capacity of the masseter muscle as measured by COX activity.
早期研究表明，在生长活跃的大鼠三叉神经运动核内运动神经元附近植入促甲状腺激素释放激素（TRH）微球会产生两个重要结果：肌肉质量增加以及植入侧咀嚼肌颜色变深。这些现象与神经肌肉活动模式和生物力学力的改变有关，而这些改变会直接影响颅面的生长发育。现在，研究了在三叉神经运动神经元附近植入TRH微球是否会影响植入侧咬肌的氧化能力。对35日龄进行立体定向手术后的TRH组（n = 5）和空白微球组（n = 6）Sprague-Dawley大鼠的植入侧和非植入侧咬肌进行了细胞色素C氧化酶（COX）测定。植入后14天对两组的分析显示，TRH植入大鼠植入侧咬肌的COX活性水平显著（P≤0.05）高于非植入侧咬肌；植入空白微球的大鼠植入侧和非植入侧咬肌的COX活性水平无显著差异。因此，上述无效假设被拒绝。这些数据表明，在三叉神经运动神经元附近植入TRH会使咬肌的氧化能力增加，这通过COX活性来衡量。
