Improved Rodent Model of Myocardial Ischemia and Reperfusion Injury

This Myocardial Ischemia reperfusion model is improved by a self-made retractor, polyvinyl chloride chloride tube, and a unique knotting method. This technique is associated with a higher survival rate and a larger impact size. This method will improve the survival rate of Myocardial Ischemia reperfusion injury in rats which will bring light to the clinical therapy of Myocardial Ischemia reperfusion injury in the future.

After anesthetizing the rat, straighten the middle section of two paper clips to form an S shape and pull down the wide section of each S to form a small retractor. Cut a two millimeter diameter polyvinyl chloride tube into seven millimeter length pieces. Insert a 10 centimeter long 4-0 suture into the PVC tube and tie its ends.

Then cut a groove in the middle of the PVC tube using ophthalmic scissors to place the suture in the period of ligation. Fix the limbs of the rat with tape by placing the rat on the surgical board in the supine position. Shave the neck and left anterior chest area with depilatory cream and clean the skin with 75%alcohol and iodophor scrub.

Then cut the skin of the neck lengthwise along the median cervical line using ophthalmic scissors. Separate the neck muscles using ophthalmic tweezers and place a retractor on each side to retract them further. After exposing the trachea, identify the space between the fourth and fifth tracheal rings.

Make a three millimeter incision parallel to the cricoid cartilage between the fourth and fifth tracheal rings with the blunt edge of a needle tip. Insert a suction trocar into the trachea through the incision and mechanically ventilate the rat to maintain normal respiration at a rate of 80 breaths per minute and a tidal volume of eight milliliters per kilogram. Next, make a four to five centimeter long incision from the xiphoid to the middle of the second left intercostal space while holding the scaffold at a 45 degrees angle.

Gently and slowly separate the pectorals major and serratus anterior muscles using ophthalmic tweezers to access the intercostal space. Make a 1.5 centimeter incision transversely between the left, third, and fourth ribs, using ophthalmic scissors. To prevent injuries, place cotton balls soaked in the physiological saline solution above the lungs in the thoracic cavity.

Dissect the pericardium using ophthalmic tweezers. Then lift the left atrial appendage by tweezers and identify the coronary ostium present at the root of the aortic artery. In the section between the left lung and auricle, ligate the LAD and the preprepared short tube together using a 6-0 surgical suture.

Tie them using a slip knot and place the slip knot in the groove of the PVC tube. Then tighten the ligated tube and LAD using a second slip knot for 45 minutes. Record the color change in the anterior part of the left ventricle and ST segment elevation on the electrocardiogram during the ischemia period.

Clamp the chest muscles and skin using an artery clip and cover the wound with moist saline gauze, then loosen the slip knot and remove the preprepared short tube after 45 minutes. Rats that underwent either existing or improved Myocardial Ischemia and reperfusion injury procedures had myocardial infarctions while rats from the sham group did not. Further, the existing and experimental Myocardial Ischemia and reperfusion injury model groups had a significant difference in myocardial infarct size.

The experimental model group had a larger myocardial infarct size than the existing model group. Hematoxylin, eosin, and Masson staining show that the cardiomyocytes of both the experimental and the existing model groups had experienced critical damage and nucleosis while getting infiltrated by numerous neutrophils. The rats in the existing and experimental Myocardial Ischemia and reperfusion injury model groups show elevated electrocardiogram STT segments than the sham group.

There were significant differences between the experimental model and sham group or the existing model and sham groups. Furthermore, the TT segment was more elevated in the experimental model group than in the existing model group. The survival rate was significantly different between the two Myocardial Ischemia and reperfusion injury model groups.

The mortality rate was 40%during the reperfusion period, while in the experimental model group, none of the rats died during surgery, demonstrating that the current improved model had a higher survival rate. The most important thing is that we should put the tube into the knot. Meanwhile, place the slip knot into the groove of the tube.

This method can also provide insight into the area of Myocardial Ischemia reprovision injury and myocardial infection.