Serial Ultrasound-Guided Percutaneous Liver Biopsy in a Partial Hepatectomy Porcine Model: A New Technique in the Study of Liver Regeneration

Abstract

Studies on liver regeneration are often carried out on small animal models such as the rat. The use of large animal models however has many advantages. Repeated biopsies of the liver may be carried out and the animal can thus serve as its own control. Sequential changes in the regenerative response to various putative hepatotrophic factors can therefore be studied. Ultrasound-guided percutaneous biopsy (USGPB) of the liver, a technique widely used in clinical practice to obtain liver samples, offers a means for repeated liver biopsies. This study was carried out to validate the use of serial USGPB of the liver as a research technique in the study of liver regeneration in a porcine hepatectomy model. Material and method: Left hepatectomy was carried out in nine Yorkshire pigs (20–30 kg). Bromodeoxyuridine (BrdU) at 50 mg/kg BW was administered daily for the first 5 days after surgery. USGPB was carried out 1 hr later using 16F biopsy needles in a Biopty device. Ultrasonography was carried out using an Acuson XP10 color doppler ultrasound machine. Immunoperoxidase staining of the biopsy specimens was performed using mouse monoclonal antibody to BrdU. Regenerating cells were identified and labeling indices constructed for each day after hepatectomy. All animals were sacrificed at the end of the study and postmortem was performed. Results and conclusion: USGPB was successful at every attempt and no animal suffered complications following the procedure. Median cumulative labeling indices increased rapidly after hepatectomy and the steepest rise occurred between the third and fourth day after surgery when it increased from 2.25 to 3.40% before leveling off. These results are consistent with those obtained by other reported techniques. USGPB of the liver overcomes the need for repeated laparotomies to obtain biopsy samples in a large animal model and has no morbidity and mortality that could lead to animal wastage.