Maeda N, Kawasaki T, Osawa K, Yamamoto Y, Sumida H, Masuda T, Kumegawa M
Acta Anat (Basel). 1987;128(4):326-33. doi: 10.1159/000146360.
Muscle fibers of the masseter muscle of mice which had been fed a fine-grained diet for various periods were studied histochemically and morphometrically. The diameters of both extrafusal and intrafusal muscle fibers decreased with time in mice fed a fine-grained diet, compared with those of control mice. In animals maintained on the special diet for 160 days after weaning at the 20th postnatal day, the effects of the diet on the diameter of muscle spindles were severe, and the diameter of each type of red and white fibers was significantly smaller than those of control animals. But a significant difference was not recognized in the diameter of intermediate fibers between control and treated mice. Unexpectedly, white fibers having a smaller diameter than red fibers were observed in diet-fed mice after the 180th postnatal day, although white fibers having such small diameter were not detectable in control animals. Succinic dehydrogenase activities were decreased in both extrafusal and intrafusal fibers of experimental animals. Moreover, muscle spindles with no annulospiral endings were increased in number in mice fed the diet for 130 and 160 days after weaning, although those spindles also increased in control animals. The diameters of outer capsules and primary endings were also significantly decreased in the animals kept on the diet for a long time. These effects of the fine-grained diet on the mouse masseter muscle became severer with time.
对不同时间段食用细颗粒饲料的小鼠咬肌肌纤维进行了组织化学和形态计量学研究。与对照小鼠相比，食用细颗粒饲料的小鼠的梭外肌纤维和梭内肌纤维直径均随时间减小。在出生后第20天断奶后以特殊饲料饲养160天的动物中，饲料对肌梭直径的影响严重，每种类型的红肌纤维和白肌纤维直径均显著小于对照动物。但对照小鼠和处理小鼠的中间纤维直径未发现显著差异。出乎意料的是，出生后第180天之后，食用饲料的小鼠中观察到直径小于红肌纤维的白肌纤维，尽管对照动物中未检测到如此小直径的白肌纤维。实验动物的梭外肌纤维和梭内肌纤维中的琥珀酸脱氢酶活性均降低。此外，断奶后食用饲料130天和160天的小鼠中无环螺旋末梢的肌梭数量增加，尽管对照动物中的这些梭也增加。长期食用该饲料的动物的外囊和初级末梢直径也显著减小。细颗粒饲料对小鼠咬肌的这些影响随时间变得更严重。
