Role of metalloproteinases and satellite cells in soleus muscle during aging

• Grant number: 15/20453-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2016
• End date: December 31, 2016
• Field of knowledge: Biological Sciences - Morphology - Histology
• Principal Investigator: Maeli Dal Pai
• Grantee: Jéssica Silvino Valente
• Host Institution: Instituto de Biociências (IBB). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

In aging there is a progressive decline in muscle strength, which is a physiological process that generates muscle weakness, increasing the risk of falling, especially in the elderly and may lead to death. Muscle regeneration is also altered in aging, which leads to a deficiency in this process and impairment of muscle mass maintenance, due to a decrease in the number or activity of satellite cells (CS). CS are undifferentiated myogenic cells that can be activated in response to severe or adaptive microlesions, and that is an important process for the regeneration, maintenance and turnover of muscle mass. These cells expressed myogenic markers, such as Pax7 in the quiescent state, and myogenic regulatory factors such as MyoD, and Myogenin. During muscle regeneration, CS migrate towards the extracellular matrix that plays an important role in the activation and proliferation of these cells. MMPs (Metalloproteinases) from extracellular matrix, are endoprotease capable to cleave extracellular matrix components such as collagen, elastin and fibrillin, and they have a key role in this process. The objective of this study is to evaluate the role of MMPs and satellite cells in the soleus muscle during aging. 24 male Wistar rats aged for 3, 12 and 22 months will be used. At the end of the experiment the animals will be weighed and sacrified and the soleus muscle Will be collect for morphological, molecular and protein analysis. For morphological analysis will be performed the hematoxylin-eosin staining and then measured the Cross Section Area (CSA) of muscle fibers. The analysis of MyoD, Myogenin, Pax 7, MMP-2 and MMP-14 and Collagen1A1 gene expression Will be performed by RT-qPCR and the analysis of protein expression Will be performed by Western Blot. The proteolytic analysis of MMP-2 and MMP-9 will be held by zymography technique. Data will be submitted to appropriate statistical analysis.