Research about the mechanism in masticatory muscle dysfunctional induced by hemimastication / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study the mechanism in masticatory muscle dysfunctional induced by hemimastication.</p><p><b>METHODS</b>Ca2+ contents were measured with atomic absorption spectrometry; calcinuerin were measured with colorimetric method; muscle fiber types were measured with adenosine-triphosphate (ATPase) staining.</p><p><b>RESULTS</b>(1) Compared with the controls, Ca2+ contents in experimental group had the higher level except 8 weeks (P < 0.05). (2) The ratio of slow fiber in experimental group increased, higher than the match groups (P < 0.05). (3) With Ca2 contents rise, the activities of calcinuerin present a bell-like shape. (4) The ratio of slow-type fiber was positively correlated to the activities of calcinuerin (r = 0.876, P < 0.05).</p><p><b>CONCLUSION</b>The signal way of muscle fiber growth and fiber transformation were activated by high concentration of calcium, then, muscle fiber transferred from fast to slow type. It may play an important role in the mechanism that hemimastication result in masticatory muscles dysfunction.</p>

A preliminary study on the effects of the exogenous creatine phosphate on rat masseter muscle after unilateral chew / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study the effect of energy therapy on Ca2+ concentration and Ca2+ -ATP enzyme activity in rat master muscle after unilateral chew, and to discuss the protective action of the exogenous creatine phosphate on rat masseter muscle after unilateral chew.</p><p><b>METHODS</b>The 20 rats were randomly divided into 4 groups, A: Creatine phosphate normal control group; B: Creatine phosphate experimental group; C: Saline normal control group; D: Saline experimental group. The Ca2+ concentration were determined by atomic absorption spectrophotometry, the activity of the Ca2+ -ATP enzyme were determined by super-micro volume Ca2+ -ATP enzyme kit.</p><p><b>RESULTS</b>(1) The Ca2+ concentration of the extraction side of group D which received the saline injection had significant difference compared with the non-extraction side (P = 0.007), the group C (P = 0.009) and the extraction side of group B (P = 0.01); (2) Ca2+ -ATP enzyme activity of group D were higher than its non-extraction side (P = 0.001), group C (P = 0.003) and the extraction side of group B (P = 0.001); (3) The ultrastructural changes of the rat masseter muscle under transmission electron microscope were as follows: The extraction side of group D have more severe pathological manifestations than non-extraction side. Both the extraction side and the non-extraction side of group B had a similar manifestation to the normal control group.</p><p><b>CONCLUSION</b>Exogenous energy material, creatine phosphate, may have certain degree of protective effect on rat masseter muscles after unilateral chew. And it may become a possible way to improve the injury of the masseter muscle.</p>