Changes in the Expression of Myosins During Postnatal Development of Masseter Muscle in the Microphthalmic Mouse

In the present study, to elucidate the influences of the deficiency of teeth on the masseter muscle, we analyzed changes in the expression of MyHC isoform mRNAs during postnatal development inmi/mimice using real-time PCR. By 8 weeks of age, MyHC I had nearly disappeared in the +/+ mice, while it was still present in themi/mi, and the level of MyHC I mRNA in themi/miwas 5.1-fold higher than that in the+/+(pmi/mimice were 41 ~ 55% lower than those in the+/+at both 3 weeks and 4 weeks of age (pmi/miand+/+. From these results, we speculate that the deficiency of teeth affects the masseter muscles during the postnatal development.