High intensity exercise increases expression of matrix metalloproteinases in fast skeletal muscle fibres

摘要: Metalloproteinases (MMPs) are proteolytic enzymes that function in the extracellular matrix to degrade connective tissues. While it is clear exercise-induced injury skeletal muscle promotes increased expression of MMPs, relationship between exercise intensity and MMPs muscles unknown. These experiments tested hypothesis metalloproteinases (MMP-2 MMP-9) dose-dependent such high-intensity endurance increases MMP whereas low-intensity will not promote muscles. Female rats (4 months old) completed 2 weeks treadmill running at either low (18 m min(-1); approximately 50% maximum oxygen consumption rate ) or high (32 70% ; up 50 min day(-1)). Non-running, sedentary animals served as controls. Muscle mRNA protein levels MMP-2 MMP-9 were assessed gastrocnemius, quadriceps soleus by reverse transcriptase-polymerase chain reaction Western blotting, respectively. Results indicate did alter any these Further, our data reveal investigated. In contrast, both containing a percentage fast type II fibres (i.e. gastronemius superficial quadriceps). results support required influence on dominant fibres.