Article

The aim of this study was to assess the effect of neuromuscular
electrical stimulation (NMES) on the extracellular matrix remodeling of the
quadriceps muscle after anterior cruciate ligament (ACL) transection in rats. The
hypothesis of this study was that ACL transection would induce maladaptive
modifications in the extracellular matrix through the increase in connective
tissue (CT) accumulation and net degradation of type IV collagen of the
quadriceps muscle. In addition, clinical-like NMES, applied to the quadriceps
muscle immediately after the ACL transection, would reduce the accumulation of
the CT content and net degradation of type IV collagen. DESIGN: Wistar male rats
were randomized into five different groups: ACL (surgery and ACL transection),
Sham (surgery without ACL transection), ACLES (surgery, ACL transection, and
NMES), ShamES (surgery without ACL transection, but NMES), and Control (intact
animals). The vastus medialis, rectus femoris, and vastus lateralis muscles of
the quadriceps were harvested 1, 2, 3, 7, and 15 days after surgery. Matrix
metalloproteinase-2 (MMP-2) (messenger RNA [mRNA] levels and activity), collagen
IV (mRNA and protein levels), and CT density were assessed. RESULTS: The ACL
transection increased the CT content and MMP-2 mRNA levels and decreased collagen
IV mRNA and protein levels. NMES minimized the CT density in all muscles and
reduced the MMP-2 mRNA levels mainly in the vastus lateralis muscle at 7 days.
Moreover, type IV collagen mRNA levels were increased in all muscles at 7 days,
as was the protein level only at 15 days, in the NMES groups. CONCLUSIONS: This study showed that ACL transection increases CT content and MMP-2 mRNA levels and
induces rapid changes in basement membranes, causing net degradation of type IV
collagen during the first 2 wks after ACL injury. Furthermore, clinical-like NMES
minimized the accumulation of CT density, regulated the MMP-2 mRNA levels, and
increased both type IV collagen mRNA and protein levels.
- Animal

Langue : ANGLAIS