Analysis of histochemically and morphometrically in the anterior belly digastric muscle of osteopetrotic (op/op) mice

The fibers of the anterior belly digastric muscle of mice, fed a granulated diet for various periods, have been studied histochemically and morphometr ically. The diameters of the anterior belly digastric fibers in normal mice fed only a granulated diet were smaller than those in mice fed a solid die t. Differences in the succinate dehydrogenase (SDH) activity of muscle fibe rs between op/op and normal mice gradually appeared in the anterior belly d igastric muscle and, by the age of 90 days, under-development of muscle fib ers was observed in the mid-belly region of the anterior belly digastric mu scle of op/op mice fed a granulated diet. These results indicate mechanical stress in mastication plays an important role in the development of the an terior belly digastric muscle structures.