Disuse and functional overload induced by tooth extraction alters neuromuscular morphology in C57BL/6J mice.
Disuse and functional overload induced by tooth extraction alters neuromuscular morphology in C57BL/6J mice.
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拔牙引起的废用和功能超负荷改变了 C57BL/6J 小鼠的神经肌肉形态。
DOI：
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发表时间：
1999
影响因子：
1.6
通讯作者：
M. K. El Kerdany
中科院分区：
文献类型：
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作者：
M. Fahim;M. K. El Kerdany
研究了功能性废用和超负荷对8月龄C57BL/6J小鼠咬肌神经肌肉接头(NMJ)形态的影响。为了刺激因牙齿缺失而引起的废用，从10只小鼠的一个上腹部拔出牙齿。拔牙的一侧因不能达到咬合而被功能性废弃(D)。同样，完整的对侧(CL)也经历了过载。分别在拔牙后7天(7d)和4个月(4m)对对照动物和处理动物的ZIO染色的NMJ进行形态测量。数据分析采用重复测量多变量协方差分析(MANCOVA)。实验动物没有减轻体重，这表明拔牙后摄入了足够的食物。7D组的纤维直径小于对照组，而4M组的纤维直径大于对照组。在7D和4M动物中，CL纤维均大于D纤维。与同年龄的对照动物相比，400万只动物的NMJ有增大的趋势。来自4M动物CL侧的NMJ神经末梢面积增加了14%(p<；0。1)，而在4M D侧，它们增加了6%(p<；0.10)。4M D组NMJ神经末梢延长5%(p<；0.07)，而4M CL组NMJ延长6%(p<；0.05)。D侧的NMJ面积比CL侧小5%，CL侧的NMJ面积小11%(p<；0.1)。7D组动物的神经末梢比对照组延长6%(p<；0.05)。拔牙后NMJ形态的改变可能是由于神经末梢的变性-再生不同所致。急性停用和超负荷可能会产生更大的神经末梢收缩，而慢性变化包括以NMJ可塑性为特征的恢复，其特征与运动、停用和衰老研究中观察到的相似。
The effects of functional disuse and overload on the morphology of neuromuscular junctions (NMJ) in masseter muscles of 8 month old C57BL/6J mice were studied. In order to stimulate disuse caused by tooth loss, teeth were extracted from one upper quadrant of 10 mice. The side where teeth were removed was functionally disused (D), since occlusion could not be achieved. Similarly, the intact contralateral (CL) side experienced overload. Morphological measurements were taken of zinc iodide osmium (ZIO)-stained NMJs from control animals, and treated animals at 7 days (7D) and 4 months (4M) post-extraction. Data was analyzed with repeated measures multivariate analysis of covariance (MANCOVA). Test animals did not lose weight, which indicated that sufficient food was consumed after tooth extraction. Fiber diameters from the 7D group were smaller than the controls, while those from the 4M animals were larger. In both the 7D and 4M animals, the CL fibers were larger than the D fibers. There was a trend towards larger NMJs in the 4M animals than in control animals of the same age. NMJs from the CL side of the 4M animals had 14% larger nerve terminal areas (p<0. 1), while on the 4M D side they were 6% larger (p<0.10). NMJs from the 4M D group had 5% longer nerve terminals (p<0.07), while the 4M CL NMJs were 6% longer (p<0.05). NMJs from the D side of the 7D animals were 5% smaller in area while on the CL side they were 11% smaller (p<0.1). Nerve terminals in 7D animals were 6% longer (p<0.05) than in controls. Changes in NMJ morphology following tooth extraction were probably due to differences in degeneration -regeneration of nerve terminals. Acute disuse and overload probably produced greater nerve terminal retraction, whereas chronic changes consisted of a recovery characterized by NMJ plasticity similar to that observed in exercise, disuse and aging studies.