minimally-invasive-muscle-embedding-mime-novel-experimental-technique

Minimally Invasive Muscle Embedding (MIME) - A Novel Experimental Technique to Facilitate Donor-Cell-Mediated Myogenesis

Skeletal muscle possesses regenerative capacity due to tissue-resident, muscle-fiber-generating (myogenic) satellite cells (SCs), which can form new ...

dosage-adjusted-resistance-training-mice-with-reduced-risk-muscle

Dosage-Adjusted Resistance Training in Mice with a Reduced Risk of Muscle Damage

Progressive resistance training (PRT), which involves performing muscle contractions against progressively greater external loads, can increase muscle ...

Wayne State University

We performed a placebo-controlled pre-clinical study to determine if sodium 4-phenylbutyrate (4PB) can reduce contraction-induced myofiber damage in the mdx mouse model of Duchenne muscular dystrophy (DMD). At 72 h post-eccentric contractions, 4PB significantly increased contractile torque and reduced myofiber damage and macrophage infiltration. We conclude that 4PB, which is approved by Health Canada (Pheburane) and the United States Food and Drug Administration (Buphenyl) for urea cycle disorders, might modify disease severity in patients with DMD.

Sodium 4-phenylbutyrate reduces myofiber damage in a mouse model of Duchenne muscular dystrophy.

B6.A-Dysf /GeneJ (BLAJ) mice model human limb-girdle muscular dystrophy 2B (LGMD2B), which is linked to mutations in the dysferlin (DYSF) gene. We tested the hypothesis that, the calcium ion (Ca ) channel blocker diltiazem (DTZ), reduces contraction-induced skeletal muscle damage, in BLAJ mice. We randomly assigned mice (N = 12; 3-4 month old males) to one of two groups - DTZ (N = 6) or vehicle (VEH, distilled water, N = 6). We conditioned mice with either DTZ or VEH for 1 week, after which, their tibialis anterior (TA) muscles were tested for contractile torque and susceptibility to injury from forced eccentric contractions. We continued dosing with DTZ or VEH for 3 days following eccentric contractions, and then studied torque recovery and muscle damage. We analyzed contractile torque before eccentric contractions, immediately after eccentric contractions, and at 3 days after eccentric contractions; and counted damaged fibers in the injured and uninjured TA muscles. We found that DTZ improved contractile torque before and immediately after forced eccentric contractions, but did not reduce delayed-onset muscle damage that was observed at 3 days after eccentric contractions.

Diltiazem improves contractile properties of skeletal muscle in dysferlin-deficient BLAJ mice, but does not reduce contraction-induced muscle damage.

We report that, labeling mouse muscle tissue, with mouse monoclonal antibodies specific to slow or fast myosin heavy chain (sMyHC and fMyHC, respectively), can lead to artefactual labeling of damaged muscle fibers, as hybrid fibers (sMyHC+ and fMyHC+).  We demonstrate that such erroneous immunophenotyping of muscle may be avoided, by performing colabeling or serial-section-labeling, to identify damaged fibers. The quadriceps femoris muscle group (QF) in 7-month-old, male, C57BL/6J mice had: 1.21 ± 0.21%, 98.34 ± 1.06%, 0.07 ± 0.01%, and 0.53 ± 0.85% fibers, that were, sMyHC+, fMyHC+, hybrid, and damaged, respectively.  All fibers in the tibialis anterior muscle (TA) of 3-month-old, male, C57BL/6J mice were fMyHC+; and at 3 days after injurious eccentric contractions, there was no fiber-type shift, but ~ 18% fibers were damaged.

Damaged muscle fibers might masquerade as hybrid fibers - a cautionary note on immunophenotyping mouse muscle with mouse monoclonal antibodies.

The aim of this study was to quantify the extent of donor-cell-derived myogenesis achieved by a novel surgical technique known as Minimally Invasive Muscle Embedding (MIME).

Minimally Invasive Muscle Embedding Generates Donor-Cell-Derived Muscle Fibers that Express Desmin and Dystrophin.

Dysferlin-deficient murine muscle sustains severe damage after repeated eccentric contractions.

Morium Begam

Wayne State University

Minimally Invasive Muscle Embedding (MIME) - A Novel Experimental Technique to Facilitate Donor-Cell-Mediated Myogenesis

Dosage-Adjusted Resistance Training in Mice with a Reduced Risk of Muscle Damage