Monitoring of Systemic and Hepatic Hemodynamic Parameters in Mice

Summary

This film demonstrates how to acquire systemic and hepatic hemodynamics in mice. The whole monitoring includes acquisition of vital parameters, systemic blood pressure, central venous pressure, common hepatic artery flow rate, and portal vein pressure as well as the portal flow rate in mice.

Abstract

The use of mouse models in experimental research is of enormous importance for the study of hepatic physiology and pathophysiological disturbances. However, due to the small size of the mouse, technical details of the intraoperative monitoring procedure suitable for the mouse were rarely described. Previously we have reported a monitoring procedure to obtain hemodynamic parameters for rats. Now, we adapted the procedure to acquire systemic and hepatic hemodynamic parameters in mice, a species ten-fold smaller than rats. This film demonstrates the instrumentation of the animals as well as the data acquisition process needed to assess systemic and hepatic hemodynamics in mice. Vital parameters, including body temperature, respiratory rate and heart rate were recorded throughout the whole procedure. Systemic hemodynamic parameters consist of carotid artery pressure (CAP) and central venous pressure (CVP). Hepatic perfusion parameters include portal vein pressure (PVP), portal flow rate as well as the flow rate of the common hepatic artery (table 1). Instrumentation and data acquisition to record the normal values was completed within 1.5 h. Systemic and hepatic hemodynamic parameters remained within normal ranges during this procedure.

This procedure is challenging but feasible. We have already applied this procedure to assess hepatic hemodynamics in normal mice as well as during 70% partial hepatectomy and in liver lobe clamping experiments. Mean PVP after resection (n= 20), was 11.41±2.94 cmH₂O which was significantly higher (P<0.05) than before resection (6.87±2.39 cmH₂O). The results of liver lobe clamping experiment indicated that this monitoring procedure is sensitive and suitable for detecting small changes in portal pressure and portal flow rate. In conclusion, this procedure is reliable in the hands of an experienced micro-surgeon but should be limited to experiments where mice are absolutely needed.

Introduction

The overall goal of this video was to demonstrate a real-time monitoring procedure for acquiring systemic and hepatic hemodynamic parameters. The rationale for developing this procedure is its great value for experimental interventions in mice that require obtaining systemic and hepatic hemodynamic parameters. The procedure can be applied to naïve animals and during or after a given hepato-biliary experimental surgical intervention, such as partial hepatectomy, portal vein ligation and liver transplantation.

Acquisition of hepatic hemodynamic data in rodents requires the proposed invasive procedure. Hepatic perfusion cannot b....

Protocol

Housing and all procedures carried out were in accordance with German Animal Welfare Legislation.

1. Sensors Calibration (Follow Manufacturer's Instructions for Sensors Calibration)

1.1) Millar catheter calibration. Pre-soak the tip of the catheter in sterile water or saline for 30 min prior to balance (zeroing) and calibration.

1. Connect the millar sensor to the millar1 channel of bridge amplifier and insert the millar sensor tip into water column.
2. Set the water column value to 0 cmH₂O. In data analysis software window, choose bridge amplify and zero it. The baseline value 0 ....

Results

Vital parameters of the mice such as respiratory rate and heart rate are obviously much higher than in rat. Mean systemic blood pressure and jugular vein pressure are similar to rat values and even similar to the human data.

Hepatic hemodynamic data are obviously different. We obtained normal values from 8 mice. Portal blood flow in normal mice ranged between 1.6 to 2.3 ml/min. Flow in the common hepatic artery ranged from 0.10 to 0.35 ml/min. Portal vein pressure in normal animals was in the .......

Discussion

Monitoring of hepatic hemodynamics is an important research tool in hepatology and hepatobiliary surgery. Acquisition of hepatic hemodynamic data helps to characterize the effect of hepatobiliary procedures on the circulatory system. Acquisition of hepatic hemodynamic data is also needed to study the effect of drugs affecting portal pressure and portal flow, e.g., as needed in studies evaluating vasoactive drugs.

Despite the small size, the vital parameters, systemic and hepatic hemod.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
PowerLab 16/30	ADInstruments	PL3516
Quad Bridge Amp	ADInstruments	FE224	Bridge amplifier
Animal Bio Amp	ADInstruments	FE136
Needle Electrodes for FE136 (3 pk)	ADInstruments	MLA1213
Perivascular Flowmeter Module	Transonic	TS420
Flowprobe MA0.5PSB/MA1PSB	Transonic	MA0.5PSB/MA1PSB
SPR-1000 Mouse Pressure Catheter	Millar instruments	841-0001
fluid filled catheter	Terumo	SR+DU2619PX	26G, 0.64×19mm
micro scissors	F·S·L	No. 14058-09
micro serrefine	F·S·L	No.18055-05
Micro clamps applicator	F·S·L	No. 18057-14
Straight micro forceps	F·S·L	No. 00632-11
Curved micro forceps	F·S·L	No. 00649-11
needle-holder	F·S·L	No. 12061-01
6-0 silk	ethicon
6-0 prolene	ethicon
7-0 prolene	ethicon
10-0 prolene	ethicon
Tail cut-off device	Kent Scientific		www.kentscientific.com
LabChart7	ADInstruments		data  analysis software