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Pericytes Contribute to Exercise‐Induced Skeletal Muscle Hypertrophy
Author(s) -
Zou Kai,
Huntsman Heather D.,
Valero Carmen,
Skelton John T.,
Adams Joseph T.,
Mahmassani Ziad,
Boppart Marni D.
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.856.3
Subject(s) - pericyte , muscle hypertrophy , skeletal muscle , cd146 , medicine , endocrinology , gastrocnemius muscle , stem cell , chemistry , biology , microbiology and biotechnology , endothelial stem cell , cd34 , biochemistry , in vitro
Pericytes are perivascular cells with stem cell potential found in a variety of tissues. We have demonstrated that pericytes accumulate in skeletal muscle overexpressing the α7 integrin (α7Tg) and α7Tg mice exhibit increased muscle growth following exercise. PURPOSE The purpose of this study was to determine whether pericytes contribute to muscle growth and whether this effect is enhanced by exercise. METHOD Sca‐1 + CD45 − cells were isolated from α7Tg gastrocnemius (GAS), and labeled with DiI. Recipient C57BL6 mice were exposed to 30 min downhill running 1 hour before cell injection (4 × 10 4 ) into GAS. The contralateral leg was injected with saline. Animals were then assigned to either sedentary (SED) or exercise trained (EX) group. EX mice were exposed to downhill running 3 times/wk for 2 wks. RESULTS Sca‐1 + CD45 − cells expressed pericyte markers (CD90, CD140b, NG2, and CD146). DiI‐labeled pericytes did not directly form new fibers and did not fuse with existing fibers. However, Pax7 + satellite cells, mean fiber cross sectional area, percentage of larger caliber fibers (2000 to 3000 μm 2 ) and number of nuclei per fiber were significantly increased in Cell/EX compared to Saline/EX (P<0.05). CONCLUSIONS This study demonstrates that exercise enhances the ability for pericytes to indirectly increase muscle growth and may provide the mechanistic basis for exercise‐induced hypertrophy.