The Superficial Masseter Muscle Cells Apoptosis After The Function Mandibular Advancement In Juvenile Rats

Objective The purpose of this study is to evaluate the relationship of the apoptotic superficial masseter muscle cells after functional mandibular advancement on juvenile rats. Methods Fifty 5-week-old male Sprague-Dawley(SD) rats were randomly divided into experimental and control groups. The mimic functional appliances were only used in experimental groups, and the rats of two groups were killed after 1,7,14,21,28 days.The erminal deoxynucleotidyl transferase-mediated deoxyuridine 5-triphosphate nick and labeling (TUNEL) and Hoechst 33258method were used to detect superficial masseter muscle cells apoptosis. Bax and Bcl-2 expression was observed by PCR. Results①NF-κB, Bax and Bcl-2 expression and the value of Bax/Bcl-2 increased after insertion of the appliance, at peak on the 21st day and then decreased.②Also, the apoptotic cells increased after insertion of the appliance, at peak on the 21st day and then decreased. Conclusion①NF-κB activating and the increased value of Bax/Bcl-2 promoted superficial masseter muscle cells apoptosis.②Superficial masseter muscles cells appeared apoptosis and rebuilt after functional mandibular advancement.