The aim of this procedure is to induce liver ischemia for the study of reperfusion injury. This is accomplished by first exposing the lobes of the liver. The next step is to expose the left liver triad, which includes the poral vein, hepatic artery, and bile duct.
Once isolated, a suture is stitched around the left triad, and a hanging weight system is applied to induce liver ischemia At a certain time point after ischemia, the weights are lifted to begin reperfusion. Ultimately, the extent of liver injury following ischemia and reperfusion can be obtained by measuring a LT and a ST in the blood and performing liver histology. The main advantage of this technique over existing methods like utilizing clamps for liver ischemia is that the suture does not cause injury to the liver tissue and that the timing of ischemia can be more precise.
Visual demonstration of this method is critical as the exact placement of the suture is key to obtaining reproducible liver ischemia without harming the tissue. Begin by setting up the surgical area with sterilized instruments and all other materials required for surgery. To start place an anesthetized mouse in a supine position on a temperature controlled heated table.
Secure the upper and lower extremities to the table with removable tape to make Locating the triad and placing the suture easier. Position the mouse and heating table such that the tail is directed to the surgeon. Next, insert a rectal probe attached to a thermal feedback controller to maintain the body temperature.
Cover the incision area with mineral oil to prevent inhalation of mouse hair and reduce allergen exposure. Once the animal has been properly prepared, confirm the depth of anesthesia before performing a midline laparotomy. Continue cutting the linear alba until the liver can be easily exposed.
Next, use a wet cotton swab to displace the intestines and expose the portal triad. To gain a better view, shift the median and left lobe towards the diaphragm and the right lobe towards the intestine. Use bland forceps to hold down the right lobe and obtain a clear view of the left portal.
Triad and vena caver inferior. Carefully thread a suture around the left portal triad. This includes the hepatic artery, hepatic vein, and bile duct.
Use forceps to grab the tip of the needle from the right side and pull the suture gently through without damaging the liver. The stitch should be placed just under the triad any deeper, and it may injure the vena caver inferior. Once the suture is in place, attach a weighted eend orph tube to each end.
When ready, these weights will be placed over suture holders that are located distally of the stitch. As seen here to initiate ischemia, tra both weights over the suture holders. The triad will be occluded immediately causing an interruption of the blood supply to the left and median loaves of the liver.
Successful occlusion is confirmed by the pale blanching of the median and left liver lobes. This partial hepatic ischemia model avoids mesenteric congestion by preserving blood flow to the right liver lobes. When the predetermined ischemic period is over, lift the weights to relieve the tension on the suture.
A changing color should be apparent as the liver is reperfused. Place the intestine back into the abdominal cavity and keep the liver and intestine warm with a wet swab soaked with warm water. After the reperfusion period, blood and liver tissue can be collected to assess the extent of liver damage after hepatic ischemia.
The extent of liver injury can be determined by staining the tissue with hematin and eoin. The healthy tissue seen here contains less hepatocyte, ization and swelling as compared to the ischemic liver. The liver enzymes, alanine, and minor transferase a LT and to minor transferase A ST are common markers of liver damage here.
Levels of both a LT and A ST increased when the ischemic time period was increased. One master. This technique can be done within 10 minutes if it is performed properly.
Other methods like ischemic preconditioning can be performed in order to answer additional questions in regard to liver injury due to ischemia.
