Article

The aim of this study was to assess the mRNA levels of atrogin-1,
muscle ring finger 1, and myostatin in rat quadriceps after anterior cruciate
ligament (ACL) transection. DESIGN: Wistar rats were randomized into three
different groups: ACL (surgery and ACL transection), sham (surgery without ACL
transection), and control. Vastus medialis, rectus femoris, and vastus lateralis
muscles were harvested at 1, 2, 3, 7, and 15 days after ACL transection. The mRNA
levels of atrogin-1, muscle ring finger 1, and myostatin, as well as the
ubiquitinated protein content, muscle mass, and cross-sectional area of the
muscle fibers, were evaluated. RESULTS: Elevated levels of atrogin-1, muscle ring
finger 1, and myostatin mRNA were detected in all tested muscles at most time
points. The ubiquitinated protein content was increased at 3 days in the ACL and
sham groups. The muscle mass of the ACL group was reduced at 3, 7, and 15 days
(vastus lateralis and vastus medialis) and at 7 and 15 days (rectus femoris),
whereas it was reduced in the sham group at 3 and 7 days (vastus lateralis and
vastus medialis) and at 7 days (rectus femoris). The cross-sectional area of
vastus medialis was reduced at 3, 7, and 15 days in the ACL group and at 3 and 7
days in the sham group. The cross-sectional area of the vastus lateralis was
reduced at 7 and 15 days in the ACL group and at 7 days in the sham group.
Whereas muscle mass and cross-sectional area recovery was noted in the sham
group, no recovery was observed in the ACL group. CONCLUSIONS: Quadriceps atrophy
after ACL transection involves increased levels of myostatin, atrogin-1, and
muscle ring finger 1 mRNA and the accumulation of ubiquitinated protein.

Langue : ANGLAIS