A Murine Model of Cervical Spinal Cord Injury to Study Post-lesional Respiratory Neuroplasticity

The overall goal of this procedure is to produce a quantifiable, reliable, and reproducible preclinical animal model of respiratory and non respiratory insufficiency induced by a cervical spinal cord injury. This is accomplished by first preparing the instruments and the drugs required for the procedure. The second step is to anesthetize the animal, then intubate it and connect it to a rodent ventilator.

Next, the spinal cord is exposed and the cervical spinal injury is induced. After sewing up the animal, the anesthesia is removed and appropriate post-surgical care is provided. Ultimately, histological techniques, as well as nerve and muscle recordings are used to examine the extent and effects of the cervical injury.

The main advantage of this technique over existing methods, such as panel cord contusion, is that the injury is smaller and well-defined. Demonstrating the procedure will be a m an engineer from my laboratory In preparation for surgery, clean and autoclave the surgical instruments. Also prepare a two by one milliliter syringe with the pre-anesthetic drugs and complete the volume to one milliliter with lactated ringers In another syringe, prepare the reversal for the pre-anesthetic drugs After subcutaneously, administering the solution of pre-anesthetic drugs, put the animal back in a cage and wait about 20 minutes until the sedative effect appears.

Then place the rat into a closed chamber, filled up with 5%isof fluorine in a hundred percent oxygen, and wait about 30 seconds until the respiratory rhythm slows down. Then remove the rat from the chamber and place it onto the intubation table on its back. Now, secure the head by placing a strap to attach the front teeth to the table.

Using a fiber optic light illuminate the thoracic space. Then place a laryngoscope in the animal's mouth to visualize the vocal cords. Next slide, an or tracheal guide into the trachea between the vocal chords, and then slide the orotracheal tube on the guide.

Then remove the guide and place a laryngeal mirror at the end of the orotracheal tube to check for moisture confirming that the tube is placed in the trachea. Following this, connect the tube to a ventilator and adjust the concentration of fluorine to 2%Then secure the orotracheal tube to the animal snout with surgical tape. For the surgery, turn the animal over and place it on a heated surgical plate with the nose pointing at a 90 degree angle to the surgeon.

Maintain the body temperature around 37.5 degrees Celsius throughout the surgery. After shaving between the scapulas with clippers, remove the hair with gauze and clean the skin. First with Betadine, and then with 70%alcohol.

Next, use scissors to make a four to five centimeter long lateral skin incision. Roc coly between the scapulas. Cut the acromial trapezius muscle, roc coly following the tendon to prevent any bleeding.

Then dissociate the rhomboid muscle to access the spinals muscles, which surround the vertebra. Find the visible bump of the spinels muscle. This marks the location of the C two vertebras prominent apophysis.

Using this landmark, cut the spinels muscle from the C one to the C3 vertebra. Next, use sterile cotton swabs to clean the muscle around the dorsal part of the vertebra. Using a Ron Jour, carefully remove the apophysis of C two.

Then continue the laminectomy meticulously, being careful to avoid the dura and any arteries. When finished with the dorsal hemi laminectomy, the dorsal spinal cord is exposed. Holding the dura with a number 55 forceps.

Use micro scissors to dissect the dura ROS coly along C two. Then continue laterally on each rostral and coddle side. Sponge up the cerebral spinal fluid as needed to perform the spinal cord injury.

First, identify the second cervical dorsal root, which will be the first visible root. Use micro scissors to make a lateral section coddly to the second cervical dorsal root. Use sterile cotton swabs to remove any blood as needed.

Verify with a micro scalpel that the extent of the lesion is close enough to reach the midline of the spinal cord. Then use the micro scalpel to make another cut to complete the injury. Making sure that the extent of the injury goes from dorsal to ventral and lateral to the midline.

When the HEMI section is complete, suture the muscles and skin and clean the wound with Betadine saturated sterile gauze. After turning off the isof fluorine vaporizer, inject the reversal drugs intramuscularly and check the body temperature. When the animal starts to breathe against the ventilator, disconnect the tracheal tube from the ventilator and remove the tube.

Place the animal in a heated cage for recovery After surgery, give antibiotics anti-inflammatory and pain reliever drugs every 12 hours for the first two days, post-surgery and use subcutaneous fluids to prevent dehydration. On the first few postoperative days, allow rats ad libido access to jellified water for the first postoperative day and soft food and water on subsequent days, and monitor their body weight and food intake. Transverse sections of the spinal cord following C two injury allow a reconstruction of the injury.

The gray shading shows the extent of the injury prior to spinal cord injury. Phrenic nerve activity is similar on both sides of the animal following a C two partial injury. Phrenic nerve activity is abolished on the ipsilateral side, but is intact on the contralateral side at seven days post-injury.

There is a partial restoration of the ipsilateral phrenic nerve activity due to the crossed phrenic pathway. The C two partial injury abolishes the ipsilateral diaphragm activity. A slight activity appears at seven days post-injury, mainly due to activity in the crossed phrenic pathway.

The rhythmic deflection of the signal of observed on the ipsilateral side is due to the artifactual recording of the electrocardiogram. Note that following a C two injury, the contralateral diaphragm activity remains the same as before the injury and allows the animal to survive After its development. This technique paved the way for researcher in the field of respiratory physiology to explore new ative therapeutics help to improve recovery following injury.