Gelhaye M, Martrette J M, Legrand-Frossi C, Trabalon M
Physiologie du Comportement, Faculté des Sciences et Techniques, CEPE, UPR-CNRS 9010, BP 239, 54506 Vandoeuvre-lès-Nancy Cedex, France.
Respir Physiol Neurobiol. 2006 Dec;154(3):443-52. doi: 10.1016/j.resp.2005.12.010. Epub 2006 Feb 8.
The purpose of this study was to establish if early chronic oral breathing could induce an ultra-structural adaptation of the diaphragm and orofacial muscles related to oral or nasal breathing. Therefore, we performed a bilateral nasal obstruction at day 8 on rat pups and the myosin heavy chain (MHC) composition of the muscles was analyzed at day 21. Nasal obstruction and the related switch to chronic oral breathing were associated with impaired growth, atrophy of olfactory bulbs, hypertrophy of adrenal glands and reduced muscle growth for all muscles studied except the diaphragm. Furthermore, we detected a smaller decrease of MHC 2b compared to MHC 2a and 2x in levator nasolabialis, a muscle involved with nasal breathing. In masseter superficialis and anterior digastric involved with oral breathing, we observed a smaller decrease of MHC 2a compared to MHC 2b or 2x, respectively. No difference was detected in the diaphragm MHC expression of oral breathing animals. Since the relative expression of fatigue resistant MHC fiber types increased in muscles involved with oral breathing, orofacial muscles seem to present a profile in MHC adapted to the transition from nasal to oral breathing, facilitating respiration.
本研究的目的是确定早期慢性口呼吸是否会引起膈肌和口面部肌肉与经口或经鼻呼吸相关的超微结构适应性变化。因此，我们在幼鼠出生第8天进行双侧鼻阻塞，并在第21天分析肌肉的肌球蛋白重链（MHC）组成。鼻阻塞以及由此转变为慢性口呼吸与生长受损、嗅球萎缩、肾上腺肥大以及除膈肌外所有研究肌肉的肌肉生长减少有关。此外，我们检测到在参与鼻呼吸的提鼻唇肌中，与MHC 2a和2x相比，MHC 2b的减少幅度较小。在参与口呼吸的咬肌浅层和二腹肌前腹，我们分别观察到与MHC 2b或2x相比，MHC 2a的减少幅度较小。在口呼吸动物的膈肌MHC表达中未检测到差异。由于参与口呼吸的肌肉中抗疲劳MHC纤维类型的相对表达增加，口面部肌肉似乎呈现出一种MHC特征，以适应从鼻呼吸到口呼吸的转变，从而促进呼吸。
