title: Development of medial pterygoid muscle fibers in rabbits fed with a liquid diet.
abstract: OBJECTIVE
  This study aimed to investigate the influence of decreased functional load on the medial pterygoid muscle during mastication in rabbits fed with a liquid-diet.
  
  
  METHODS
  Medial pterygoid muscles from 54 rabbits (solid- and liquid-diet groups, n=48; unweaned group, n=6) were histochemically examined at 4, 9, 12, 18, and 33 weeks after birth. Six fiber types (I, IC, IIC, IIA, IIAB, and IIB) were distinguished via mATPase staining.
  
  
  RESULTS
  Significant increases in the diameters of all fiber types were seen up to 33 weeks of age in the solid-diet group; however, no significant increase was noted in fiber types I and IC, from 4 to 33 weeks of age, in the liquid-diet group. The proportion of slow fibers increased up to 12 weeks followed by an increase in the number of fast fibers in the solid-diet group, whereas in the liquid-diet group, the number of slow fiber declined after weaning.
  
  
  CONCLUSIONS
  Liquid-diet consumption caused muscle fiber atrophy and an increase in the number of fast fibers during early developmental stages after weaning. Furthermore, the growth pattern of the medial pterygoid muscle in the liquid-diet group was different from that in the solid-diet group.
authors.affiliation: Department of Orthodontics, School of Dentistry, Aichi Gakuin University, Suemori-dohri 2-11, Chikusa-ku, Nagoya 464-8651, Japan.
authors.forename: Kozue
authors.initials: K
authors.lastname: Kuroki
authors.affiliation: Department of Physiology, School of Dentistry, Aichi Gakuin University, Kusumoto-cho 1-100, Chikusa-ku, Nagoya 464-8650, Japan. Electronic address: takumi@dpc.agu.ac.jp.
authors.forename: Takumi
authors.initials: T
authors.lastname: Morita
authors.affiliation: Department of Orthodontics, School of Dentistry, Aichi Gakuin University, Suemori-dohri 2-11, Chikusa-ku, Nagoya 464-8651, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Takasu
authors.affiliation: Department of Orthodontics, School of Dentistry, Aichi Gakuin University, Suemori-dohri 2-11, Chikusa-ku, Nagoya 464-8651, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Saito
authors.affiliation: Department of Orthodontics, School of Dentistry, Aichi Gakuin University, Suemori-dohri 2-11, Chikusa-ku, Nagoya 464-8651, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Fujiwara
authors.affiliation: Department of Physiology, School of Dentistry, Aichi Gakuin University, Kusumoto-cho 1-100, Chikusa-ku, Nagoya 464-8650, Japan.
authors.forename: Katsunari
authors.initials: K
authors.lastname: Hiraba
authors.affiliation: Department of Orthodontics, School of Dentistry, Aichi Gakuin University, Suemori-dohri 2-11, Chikusa-ku, Nagoya 464-8651, Japan.
authors.forename: Shigemi
authors.initials: S
authors.lastname: Goto
mesh_terms: D000818:Animals; D001284:Atrophy; D004032:Diet / Q000379:methods*; D008297:Male; D024510:Muscle Development / Q000187:drug effects*; D018656:Muscle Fibers, Fast-Twitch / Q000473:pathology*; D011626:Pterygoid Muscles / Q000254:growth & development* / Q000473:pathology; D011817:Rabbits
keywords: Liquid diet; Medial pterygoid muscle; Muscle fiber type; Postnatal development; Rabbits