Generating a Mouse Model with a Spinal Cord Injury

All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board. 

1. Preparation of Surgical and Non-surgical Instruments

1. Sterilize the surgical and non-surgical instruments in an autoclave.
2. Clean the surgical operating table with 70% ethanol and warm a heating pad to 37 °C.
3. Place the heating pad on the operating table and cover it with sterile surgical drapes.
    NOTE: In all survival procedures, the "No Touch" technique is used here to maintain sterility.

2. Preparation of Animals and Performing the T9-T10 Spinal Laminectomy

1. Procure adult (Balb/c) 10-week-old male mice. Induce anesthesia in each animal using an inhaler, beginning with 5% isoflurane and then decreasing to 2-3% to maintain sedation for the remainder of the procedures.
2. Confirm complete anesthesia by eliciting no response to a tail/paw pinch-induced nociception stimulation.
3. Shave the hair over the dorsum (head to tail) with an electric clipper, and then apply the depilatory cream (3 min) to remove the remaining hair. Finally, wash the dorsum with running water/wet scrub and return the animals to their cages.
    NOTE: This is necessary to avoid additional irritation to the skin and chemical contamination at the time of skin wounding
4. The next day, apply ophthalmic ointment to the corneas to protect the eyes from drying during the surgical procedure. Then, scrub the skin with 3 alternative preparations of betadine scrub and 70% ethanol.
5. With a scalpel, perform a skin incision (~1.0-1.5 cm) along the midline on the back at the level of T8-T12 vertebrae.
    NOTE: The level of vertebrae is identified by back counting the vertebra from T13 using the location of floating ribs that correspond to the T13 vertebra.
6. Clear the subcutaneous adipose tissue to access the paraspinal muscles, and then dissect them slowly to expose the spinous processes and laminae on both sides.
    NOTE: Do this procedure very carefully to avoid excess bleeding or any injury to the spinal cord at this point.
7. Perform a laminectomy to expose the spinal cord (T9-T10 vertebrae) by gently peeling off the spinal lamina using microdissecting forceps.
    NOTE: Perform the laminectomy so that an excess of the spinal cord is exposed to facilitate the creation of the injury. In the control group, only the laminectomy is performed.

3. Performing the T9-T10 Complete Spinal Cord Injury (SCI)

1. Using forceps, secure the spinal column at T8 and lift to exaggerate the spinal curvature.
2. Using fine scissors, section the spinal cord between the T9 and T10 vertebra all the way to the floor of the vertebral canal to ensure complete transection.
3. After observing the complete transection under a surgical microscope, apply a piece of subcutaneous fat over the laminectomy site to provide additional protection to the spinal cord prior to surgical site closure.
4. Finally, close the wound and suture the paravertebral muscles and superficial fascia using continuous sutures, and then close the skin using suture clips.
5. Post-SCI, observe the bowel movement on the following day; however, manage the urinary bladder by manual bladder evacuation.
    NOTE: The Basso Mouse Scale (BMS) can be used to monitor the progress of hindlimb functional recovery post-SCI on day 2 and then weekly.