Maejima M, Abe S, Sakiyama K, Agematsu H, Hashimoto M, Tamatsu Y, Ide Y
Department of Anatomy, Tokyo Dental College 1-2-2 Masago, Mihama-ku, Chiba-shi, Chiba 261-8502, Japan.
Arch Oral Biol. 2005 Dec;50(12):988-93. doi: 10.1016/j.archoralbio.2005.03.007.
The purpose of this study was to clarify any changes in muscle fibre properties in different regions of murine tongue during development, and to assess the effects of functional changes including weaning on these muscle fibres. The tongue was divided into upper and lower regions at the lateral margin, and the expression of myosin heavy chain (MHC) isoforms at different ages was investigated. Expression of genes encoding MHC proteins was quantified at the transcription level by quantitative reverse transcriptase polymerase chain reaction, and the protein expression of MHC isoforms was assessed by immunostaining. No difference was found in isoform expression between the upper and lower regions of the tongue before weaning. However, the expression of MHC-2b increased markedly in both regions after weaning, while that of MHC-2a decreased. At the age of 16 weeks, the expression of MHC-2b in the lower region was greater than that in the upper region. These findings show that during weaning, when there is a shift from sucking behaviour to mastication, the expression of MHC-2b increases along with an increase in the speed and strength of muscle contraction. Also, contraction force becomes stronger in the lower region of the tongue than the upper region at the age of 16 weeks.
本研究的目的是阐明小鼠舌头不同区域在发育过程中肌纤维特性的任何变化，并评估包括断奶在内的功能变化对这些肌纤维的影响。在舌的外侧边缘将其分为上部和下部区域，并研究不同年龄时肌球蛋白重链（MHC）亚型的表达。通过定量逆转录聚合酶链反应在转录水平对编码MHC蛋白的基因表达进行定量，并通过免疫染色评估MHC亚型的蛋白表达。断奶前，舌的上部和下部区域之间的亚型表达未发现差异。然而，断奶后两个区域中MHC-2b的表达均显著增加，而MHC-2a的表达则下降。在16周龄时，下部区域中MHC-2b的表达高于上部区域。这些发现表明，在断奶期间，当从吸吮行为转变为咀嚼时，MHC-2b的表达随着肌肉收缩速度和强度的增加而增加。此外，在16周龄时，舌下部区域的收缩力比上部区域更强。
