Effects Of The Exogenous Creatine Phosphate On Rat Masseter Muscle After Unilateral Chew

Objective:To investigate the effect of the energy therapy on Ca2+ concentration and Ca2+-ATP enzyme activity in rat masseter muscle after unilateral chew. Discuss the protective action of the exogenous creatine phosphate on rat masseter muscle after unilateral chew. Intend to provide a theoretical basis for the treatment of masticatory muscle disorder syndrome in clinical.Methods:8-week-old female Wistar rats, provided by the Experimental Animal Center of Shandong University, weighting about 200g-250g. The animal model of unilateral mastication was established by upper molar teeth extraction on the left side. The 20 rats were randomly divided into 4 groups, recorded as A: creatine phosphate normal control group, daily injection of creatine phosphate, non-extraction; B:creatine phosphate experimental group, daily injection of creatine phosphate, extract the molar of the left maxillary; C:saline normal control group, daily injection of saline, non-extraction; D:saline experimental group, daily injection of saline, extract the molar of the left maxillary. After 4 weeks, animals of both groups, experimental and control, were killed by cervical dislocation. The masseter muscles of each side were dissected to prepare the tissue fluid for the detection of the related indicators. The Ca2+ concentration was measured by atomic absorption spectrophotometry, the activity of the Ca2+-ATP enzyme was measured by super-micro volume Ca2+-ATP enzyme Kit. The pathological changes of mastication muscles were studied under the TEM.Results:(1)The Ca2+ concentration of the extraction side of group D which received the saline injection was significantly higher than the non-extraction side (P=0.007<0.01), the group C (P=0.009<0.01) and the extraction side of group B(P=0.01<0.05);(2)Ca2+-ATP enzyme activity of the extraction side of group D was obviously lower than that of non-extraction side (P=0.001<0.01), group C (P=0.003<0.01) and the extraction side of group B (P=0.001<0.01);(3)The Ca2+ concentration of the extraction side of group B have no significant difference compared with the non-extraction side of group B, the normal control group A; Ca2+-ATP enzyme activity of the extraction side group B have no significant difference compared with the non-extraction side of group B, the normal control group A;(4)The Ca2+ concentration and the Ca2+-ATP enzyme activity of the non-extraction side of group D have no significant difference compared with its normal group and non-extraction side of group B; The Ca2+ concentration and the Ca2+-ATP enzyme activity of the non-extraction side of group B have no significant difference compared with its normal group;(5)The ultrastructural changes of the rat masseter muscle under TEM:Both the extraction side and the non-extraction side of group B have a similar manifestation to the normal control group. The muscle fibers show normal features, with tightly packed myofibrils and mitochondria with many cristae. And the blood capillaries show normal features, with open lumina; The extraction side of group D show a more severe pathological manifestations than its non-extraction side. The muscle fibers show intermyofibrillar edema, swollen mitochondria with disrupted cristae and the capillary contracture.Conclusions:This study shows that the Ca2+ concentration of the masseter increased and the Ca2+-ATP enzyme activity decreased after unilateral chew. We can see the pathological changes of mastication muscles under the TEM. Exogenous energy material--creatine phosphate may have certa in protection to rat masseter muscle after unilateral chew, and it may become a possible way to improve the injury of the masseter muscle.