FDB Muscle Dissection from Mice

This protocol is modified from section 3.1.2 of Isolation and Culture of Skeletal Muscle Myofibers as a Means to Analyze Satellite Cells and the first part of the following video with accompanying protocol DNA Electroporation, Isolation and Imaging of Myofibers | Protocol.

Materials

• Tweezers
• Standard operating scissors
• Surgical scissors
• Forceps
• Dissection stage with 7 pins
• Anesthetic

Flexor Digitorum Brevis Muscle Extraction

• Sacrifice the animal with anesthetic gas inhalation followed by cervical dislocation to ensure death.
• Remove the hind feet above the ankle joint using standard operating scissors.
• Pin one foot tight, sole facing up, onto the dissection stage with pins through each of the 5 toe tips and one through the plantar side of the ankle.
• Starting at the ankle, snip the skin straight up the side of the foot along the hairline towards the toes, being careful not to nick the muscle beneath the skin. Repeat on the other side of foot.
• Holding the skin at the base of the ankle with forceps, cut the skin across the heel.
• Lift the skin flap with forceps. With your scissors pointed toward the skin, parallel with the tendons so as to not nick the muscle, snip the underlying connective tissue, effectively removing the skin.
• Continue snipping connective tissue and gently pulling up on the skin until the tendons of the digits are exposed. Pin the skin onto the stage above the foot.
• To isolate the tendons, insert tweezers between the bone and the 5 tendons below where the muscle becomes thicker. Leave enough room to grasp the bundle of tendons with the forceps below the tweezers.
• Grasp the tendon bundle at the base, below the tweezers, ensuring that the muscle tissue is not damaged. Remove tweezers. To remove the FDB muscle bundle, cut the large tendon at the heel to free the tendon from the bone. Holding the tendon with forceps, dissect the FDB bundle from the large white tendon, carefully removing any connective tissue attached to the FDB with scissors. If done properly the bundle will easily lift off of the underlying tendons revealing bright white tendons leading to the individual digits. Cut the FDB at the tendons near the toes freeing the bundle from the foot. Err on the side of retaining tendon tissue on the dissected muscle and avoid damaging the FDB muscle.
• Place the entire muscle bundle in the well containing KRBH.
• Repeat on the contralateral foot and place in the same well.