Cyclic stretch induces decorin expression via yes-associated protein in tenocytes: A possible mechanism for hyperplasia in masticatory muscle tendon-aponeurosis hyperplasia

Masticatory muscle tendon-aponeurosis hyperplasia (MMTAH) is a disease which exhibits limiting mouth opening caused by hyperplasia of the tendon and aponeurosis of bilateral masticatory muscles. Although it is unclear whether hyperplasticity of tendons in MMTAH is due to cyclic stretch, we hypothesize that cyclic stretch is the main cause of force on MMTAH. In this study, we examined decorin expression in the masticatory muscle tendon of MMTAH patients. We also examined decorin (Dcn) expression of tenocytes on which stretch forces are loaded to explore whether stretch forces affect yes-associated protein (YAP) signaling and whether Dcn expression is regulated by YAP.