Dm 600

Histopathological evaluation was conducted on three mice at each time‐point: 3rd, 5th and 14th day post‐injury. Small fragments from the left gastrocnemius muscles were collected and fixed by immersion in 4% glutaraldehyde, post‐fixed in buffered 1% OsO₄ with 1.5% K₄Fe(CN)₆ (potassium ferrocyanide–reduced osmium), dehydrated in graded ethanol series and further processed for epoxy resin embedding (AGAR 100). One‐micrometre‐thick sections (semi‐thin sections) were stained with 1% toluidine blue and examined by light microscopy for morphological analysis with Leica DM 600. Images were recorded using a Leica DFC7000 T camera.

V481 cells were plated on #1.5 thickness round coverglasses at a density of 20,000 cells/well. After 24 hours, cells were treated with Negative Control or lincDUSP-specific GapmeRs as described above. 48 hours post-transfection, cells were treated with 2 uM doxorubicin for indicated timepoints. Cells were fixed in paraformaldehyde (3.7% formaldehyde, 0.1% Triton-X, 1 × PBS) for 30 min at 37 °C followed by 1:1 acetone:methanol for 10 min at −20 °C. Coverglasses were blocked in 1% BSA/PBS at 37 °C for 30 min before incubating in 1:200 Rabbit anti-phospo-γH2AX (Cell Signaling Technology 9718 S) at 4 °C overnight. 1:500 Goat anti-Rabbit IgG AlexaFluor 488-conjugated secondary antibody (Thermo Fisher Scientific, Cat #A-11008) was used to stain cells with 1:1000 DAPI counterstain. Cells were imaged using the Leica DM600 at 100× magnification.