A Mouse Model of the Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy Procedure Aided by Microscopy

ALPPS can rapidly promote liver regeneration. However, the rodent small animal model and the mechanism of the regeneration are still insufficient. This model allows for investigating the molecular and cellular pathway involved in liver regeneration after a severe liver injury.

With the aid of ALPPS and the PMX mouse models, recent studies showed that balance of Gata3 and the Ramp2 in hepatocytes regulate hepatic muscular reconstitution in post-operative liver regeneration. Single-cell sequencing, single-cell attack sequencing, as well as single-cell CRISPR has paved the way for the discovery of previously unknown cell types and subtypes in normal and diseased liver. The ALPPS technique is used for patients with liver tumors that cannot be removed through surgery.

The ability of the remaining liver to regenerate after the procedure is crucial for the patient's survival. However, the underlying mechanism post-ALPPS remains utterly unknown. Based on the previous reports on the rat and the mouse ALPPS GeCKO models, we constructed a mouse GeCKO protocol that was consistent with clinical operation and native limb.

To begin, subcutaneously inject one milliliter of lactated Ringer solution mixed with 5%glucose into the anesthetized mice. Use small animal clippers to shave a two centimeter area on the abdominal region of the mouse. Then, make a midline incision with a surgical scalpel.

Open the incision with a pair of surgical scissors. Use an abdominal retractor to expand the incision while facilitating the gentle traction of the duodenum and a section of the small intestine with sterile, moist cotton swabs. Cover the structures with a pre-prepared sterile cotton swab to expose the hepatic segment of the portal vein.

For portal vein ligation, peel off the peritoneum and intestinal tract and circle the main portal veins branches with slow, deliberate, forward pushing and spreading movements. Identify the right posterior branch, the combined left lateral and median branches, and the caudate branch. Next, to dissect the right posterior branch, locate its prominent visible branch when traversing the hepatic hilum via the main portal vein.

Use moistened cotton balls as a fulling agent to separate the liver's middle lobe from the right posterior lobe. Dissect along the Glisson's capsule. Pull a 1.5 centimeter long silk tie around the portal vein branches.

Then, use an 8-0 silk suture to ligate the right posterior branch. For the dissection of the left lateral and median branches, first, dissect any potential interstice between the left lateral lobe and the caudate lobe. Then, introduce a pair of microforceps into the entrance created.

When resistance is felt, adjust the micro forceps slightly to move through the surface of the Glisson's capsule of the right medial lobe. Tie an 8-0 silk suture around the portal vein of the left lateral and median branches. Successful ligation can be observed by the ischemic demarcation within the liver's middle lobe, with pallor on the left lobe.

Next, dissect the caudal lobe. Fill the potential space between the main portal vein and the caudate lobe with a cotton swab. Peel away the peritoneum of the caudate lobes to visualize the portal vein branches of the lobe.

Ligate the caudate branch with a stitch-up suture, ensuring that the needle path adequately wraps the caudate branch. To transect the liver, use an electrocautery pen to create a 0.5 millimeter precut line along the demarcation line in the middle liver lobe. With a pair of microforceps and the electrocautery pen, cut the liver tissue.

Swab the bleeding with cotton. Remove the gallbladder at the end as it provides a good pulling point through transection. Use a cotton swab to apply controlled pressure for hemostasis.

Once transection and cholecystectomy are complete, carefully place the small bowel back into the abdominal cavity. Close the peritoneum and the abdominal wall with 6-0 absorbable sutures. Disinfect the skin surface, and then subcutaneously inject fentanyl and meloxicam mixed with saline to alleviate postoperative pain.

Place the mouse on a thermostatic pad to facilitate awakening. Transfer them into individual cages when they regain consciousness. Subcutaneously, inject medetomidine, continuing for 24 hours postoperatively.

Mice that were subjected to ALPPS showed a higher proclivity to cellular proliferation. Inflammatory markers of the ALPPS mice, specifically interleukin-6, were higher than those observed in the PVL group.