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Masticatory muscle dysfunction is temporomandibular joint disorder (temporomandibular disorders, TMD) is one of the main performance, including masticatory muscle soreness, fatigue and pain, generally do not have a clear structural change in muscle fibers, may be related to intracellular Ca 2 environment disorders. Our previous experiments showed that gradually induced occlusal disorders can lead to Sprague-Dawley (SD) rats temporomandibular joint degenerative changes in the animal model for the study of the microstructure of the masseter muscle, ultrastructural changes in the masseter muscle mitochondria Ca 2 content changes, muscle cell damage sensitive to changes in protein levels in serum and muscle injury related substances change and these changes with Ca 2 environment to study the relationship imbalance to explore the progressive occlusion disorder on masseter and its possible mechanism. In this study, female SD rats for the study. Firstly, push the left maxillary and right mandibular third molar distal movement gradually formed on the tip of mandibular molar occlusal fossa does not match the state, the establishment of progressive bilateral molar occlusal disorders model; Then, rat masseter microscopy, ultra- micro-structural changes in the masseter muscle mitochondrial Ca 2 content changes, muscle damage sensitive to changes in protein expression and related substances in serum content changes, and observe the calcium chelator EDTA and calcium channel blockers Nifedipine impact of these changes. Part I: eight 42-week-old female SD rats were randomly divided into control group, the operation control group, occlusal disorders group, occlusal disorders injection EDTA group, saline group occlusal disorders, occlusal disorders injection nifedipine group, occlusal disorder injection of DMSO group 7 experimental groups, observation time for the implementation of occlusal disorders after one week, two weeks, four weeks a total of three time points changes. EDTA as calcium chelator (chelate intracellular Ca 2 ), calcium antagonists nifedipine is (to prevent extracellular Ca 2 flow), both of which can block the intracellular Ca 2 role. Observations show that the light microscope occlusal disorders group at each time point of the masseter muscle structure with substantially the same as the control group, no significant microscopic structural abnormalities. Transmission electron microscopy and found that the control group, the operation control group injected EDTA group occlusal disorders, occlusal disorders nifedipine group injected muscle fiber structure are basically the same, neatly arranged myofibrils, mitochondria uniform size, arranged in neat rows, crest more; The occlusal disorders group, saline group occlusal disorders, occlusal disorders DMSO group injected some muscle fibers change into circular mitochondrial matrix electron density is reduced, fewer cristae shorter, or even disappear, accompanied by mitochondrial swelling visible sarcoplasmic reticulum vacuoles technology. Conclusion: The progressive occlusal disorders can lead to SD rats masseter slight ultrastructural disorders, and these minor changes in the ultrastructure of calcium channel blockers may be (EDTA and nifedipine) suppression. Part II: 8-week-old female SD rats were 135 randomly divided into control group, the operation control group, occlusal disorders group, occlusal disorders injection EDTA group, saline group occlusal disorders, occlusal disorders injection nifedipine group, occlusal disorders DMSO group of seven injection experimental groups were observed after the implementation of occlusal disorders 1 week, 2 weeks, 4 weeks a total of three time points changes. The rat masseter muscle tissue using gradient centrifugation after which the mitochondria were measured by atomic absorption spectrometry mitochondrial Ca 2 content to mitochondrial protein content BCA method, whichever is the ratio (μg / mg) to represent the masseter muscle mitochondrial Ca 2 relative content. The results showed that the control group and the operation control group injected EDTA group occlusal disorders, occlusal disorders injection nifedipine group had no significant difference (P gt; 0.05), while the occlusal disorders group and the saline group occlusal disorders, occlusal disorders injection DMSO No significant difference was no (P gt; 0.05), and were significantly higher than the control group operation (P lt; 0.001). Conclusion: The progressive occlusion disorder can lead to rat masseter inner mitochondrial Ca 2 were significantly increased, while calcium channel blockers (EDTA and nifedipine) can block the mitochondrial calcium content increased . Part III: 8-week-old female SD rats were randomly divided into control group operation, occlusal disorders group, occlusal disorders group and the injection of EDTA occlusal disorders nifedipine injection four experimental groups were set up after the implementation of an occlusal disorders week, 2 weeks, 4 weeks a total of three time points. The rat masseter muscle tissue injury determination which is sensitive protein desmin (desmin) and skeletal muscle troponin (skeletal muscle Troponin, sTnI) content to actin (actin) as an internal reference, respectively. the integral optical density value desmin / actin and sTnI / actin and desmin sTnI expressed relative content of desmin and sTnI found in all experimental groups did not differ significantly (P gt; 0.05). Conclusion: The progressive occlusion disorder did not cause the masseter muscle in skeletal muscle injury susceptibility protein (desmin and skeletal muscle troponin) of significant degradation. Part IV: eight 75-week-old female SD rats were randomly divided into control group, occlusal disorders group, occlusal disorders injection EDTA group, saline group occlusal disorders of four experimental groups, the establishment of one week after the implementation of occlusal disorders , two weeks, four weeks a total of three time points. The rat serum were detected by automatic biochemical analyzer creatine kinase (creatine kinase, CK) and lactate dehydrogenase (lactate dehydrogenase, LDH) activity, enzyme-linked immunosorbent assay (enzyme linked immunosorbent assay, ELISA) assay myoglobin (myoglobin, Mb) content. Found that these three substances in each experiment, no significant difference between the groups (P gt; 0.05). Conclusion: The progressive occlusion disorder did not cause serum creatine kinase, lactate dehydrogenase and myoglobin content change significantly. Through these studies, the following conclusions: 1. Gradually induced occlusal disorders can lead to swelling of the rat masseter muscle mitochondria, vacuoles, etc. sarcoplasmic reticulum ultrastructure minor injuries, these injuries and mitochondrial calcium overload, and its calcium overload may be the source of extracellular calcium influx. 2 progressive occlusion disorder did not cause damage to sensitive rat masseter muscle protein in significant degradation, but also did not cause serum creatine kinase, lactate dehydrogenase and myoglobin content change significantly.
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