Extended 78% Hepatectomy in a Mouse Surgical Model

Summary

The mouse model of partial 2/3 (66%) hepatectomy is well described in the literature, but more extended hepatectomies mimicking small-for-size syndrome after liver transplantation have seldom been used. We describe an extended 78% hepatectomy procedure in a mouse model that results in approximately 50% postoperative lethality in healthy mice.

Abstract

Partial 2/3 hepatectomy in mice is used in research to study the liver's regenerative capacity and explore outcomes of liver resection in a number of disease models. In the classical partial 2/3 hepatectomy in mice, two of the five liver lobes, namely the left and median lobes representing approximately 66% of the liver mass, are resected en bloc with an expected postoperative survival of 100%. More aggressive partial hepatectomies are technically more challenging and hence, have seldom been used in mice. Our group has developed a mouse model of an extended hepatectomy technique in which three of the five liver lobes, including the left, median, and right upper lobes, are resected separately to remove approximately 78% of the total liver mass. This extended resection, in otherwise healthy mice, leaves a remnant liver that cannot always sustain adequate and timely regeneration. Failure to regenerate ultimately results in 50% postoperative lethality within 1 week due to fulminant hepatic failure. This procedure of extended 78% hepatectomy in mice represents a unique surgical model for the study of small-for-size syndrome and the evaluation of therapeutic strategies to improve liver regeneration and outcomes in the setting of liver transplantation or extended liver resection for cancer.

Introduction

Mouse and rat surgical liver resection models, first described in 1931, are the most common experimental models utilized to study the molecular basis of liver regeneration. They could also be useful in translational science research to test and develop strategies to improve outcomes following extended liver resection or transplantation of suboptimal liver grafts^1,2,3,4. Partial hepatectomies (PH) in mice entail the removal of approximately 2/3 (66%) of the total liver mass (TLM), which when performed in healthy animals have exceptional outco....

Protocol

The methods described within this procedure protocol have been approved by the Institutional Animal Care and Use Committee (IACUC) at the Beth Israel Deaconess Medical Center (BIDMC). All experiments were completed in accordance and compliance with IACUC and the BIDMC animal research facility guidelines.

1. Mouse preoperative preparation

1. Shave the mouse abdomen from the mid-sternum to the suprapubic region with clippers.
2. Induce general anesthesia with 1-4% isoflurane in 100% oxygen. When anesthetized, place the mouse supine on the surgical field with a heating pad underneath. Before making an incision,....

Results

A successful extended 78% hepatectomy is expected to induce 50% mortality within 1 week in healthy adult mice aged 8-12 weeks¹⁶. When properly performed, minimal blood loss is expected. Residual bleeding that persists can be controlled by manual pressure. Perioperative death within 24 h of surgery is often caused by technical errors. Technical failures include inadvertent injury to large blood vessels causing intractable intraoperative hemorrhage; significant postoperative hemorrhage often due to .......

Discussion

To successfully perform an extended 78% hepatectomy causing 50% lethality in mice, it is critical that each liver lobe is precisely resected. This level of competency and precision can only be achieved if the procedure is performed repeatedly. The training curve varies between operators but typically requires 3-6 months of practice. A liver resection that removes less than 78% of the TLM would result in higher survival rates, while a liver resection that removes greater than 78% of the TLM would result in greater lethali.......

Materials

Name	Company	Catalog Number	Comments
2 x 2 Gauze	Covidien	2146	Surgery: dissection
5-O Nylon Monofilament Suture	Oasis	50-118-0631	Surgery: Skin closure
5-O Silk Suture	Fine Science Tools	18020-50	Surgery: liver lobe ligation
5-O Vicryl Suture	Ethicon	NC9335902	Surgery: Abdominal wall closure
Addson Forceps	Braintree Scientific	FC028	Surgery: dissection
Alcohol Swabs (2)	BD	326895	Disinfectant
Buprenorphine Extended Release Formulation	Zoopharm	N/A	Analgesia
Cordless Trimmer	Braintree Scientific	CLP-9868-14	Shaving
Curved Forceps	Braintree Scientific	FC0038	Surgery: dissection
Hemostat	Braintree Scientific	FC79-1	Surgery: dissection
Isoflurane Inhalant Anesthetic	Patterson Veterinary	RXISO-250	General Anesthesia
Magnet Fixator (2-slot) (2)	Braintree Scientific	ACD-001	Surgery: to hold small retractors
Magnet Fixator (4-slot)	Braintree Scientific	ACD-002	Surgery: to hold small retractors
Microscissors	Braintree Scientific	SC-MI 151	Surgery: dissection
Operating tray	Braintree Scientific	ACD-0014	Surgery: for establishment of surgical field
Povidone Iodine 10% Swabstick (2)	Medline	MDS093901ZZ	Disinfectant
Scalpel (15-blade)	Aspen Surgical Products	371615	Surgery: dissection
Sharp Scissors (Curved)	Braintree Scientific	SC-T-406	Surgery: dissection
Sharp Scissors (Straight)	Braintree Scientific	SC-T-405	Surgery: dissection
Small Cotton-Tipped Applicators	Fisher Scientific	23-400-118	Surgery: dissection
Tissue Forceps (Straight x2)	Braintree Scientific	FC1001	Surgery: dissection
Warming Pad (18" x 26")	Stryker	TP 700	Warming
Warming Pad Pump	Stryker	TP 700	Warming
Wire Handle Retractor (2)	Braintree Scientific	ACD-005	Surgery: to facilitate exposure of peritoneal cavity
Xenotec Isoflurane Small Animal Anesthesia System	Braintree Scientific	EZ-108SA	General Anesthesia: Contains Isoflurane vaborizer & console, Induction chamber, Regulator/Hose, Facemask (M)