Parabiosis in Mice: A Detailed Protocol

Summary

Parabiotic joining of two organisms leads to the development of a shared circulatory system. In this protocol, we describe the surgical steps to form a parabiotic connection between a wild-type mouse and a constitutive GFP-expressing mouse.

Abstract

Parabiosis is a surgical union of two organisms allowing sharing of the blood circulation. Attaching the skin of two animals promotes formation of microvasculature at the site of inflammation. Parabiotic partners share their circulating antigens and thus are free of adverse immune reaction. First described by Paul Bert in 1864¹, the parabiosis surgery was refined by Bunster and Meyer in 1933 to improve animal survival². In the current protocol, two mice are surgically joined following a modification of the Bunster and Meyer technique. Animals are connected through the elbow and knee joints followed by attachment of the skin allowing firm support that prevents strain on the sutured skin. Herein, we describe in detail the parabiotic joining of a ubiquitous GFP expressing mouse to a wild type (WT) mouse. Two weeks after the procedure, the pair is separated and GFP positive cells can be detected by flow cytometric analysis in the blood circulation of the WT mouse. The blood chimerism allows one to examine the contribution of the circulating cells from one animal in the other.

Introduction

Parabiosis, the surgical joining of two organisms, was first described in 1864 by Paul Bert as a way to develop a model to study shared circulatory systems and consisted of the joining of the skin and muscular walls of two rats¹. Parabiosis promotes formation of microvasculature at the site of inflammation³ and has had several applications in physiological studies, such as the hormonal communication between the pituitary gland and gonads as well as the role of the kidney in hypertension⁴. It has been further employed to investigate the recruitment and integration of progenitor cells in neovascularization⁵, migration of hemat....

Protocol

All animal studies were performed according to the guidelines of UCLA's animal care and use committee and the National Institutes of Health Guide for the Care and Use of Laboratory Animals. The duration of the procedure described below is approximately 45-60 min from beginning to end.

1. Preparation of Surgical Field

1. Perform procedure in a clean animal surgery room.
2. Equipment: isoflurane Vaporizer, Gaymer T Pump with heating pad.
3. Sterile tools: two curved forceps, fine scissors, needle holder.
4. Sterile gloves must be used during the entire procedure.

2. Preparatio....

Results

The anticipated outcome of parabiosis of two organisms is the equal contribution of each animal's circulatory system to a common blood circulation (Figure 2). One can easily verify the successful equilibration of the blood of the parabiosed WT and GFP positive mice by flow cytometric analysis. Here, venous blood was obtained from the tails of both parabionts at 2 weeks after the surgery and was fractionated for peripheral blood cells (to exclude erythrocytes). The fractionated hematopoietic-derived cell .......

Discussion

The parabiosis method discussed here presents minimal technical difficulties and results in low mortality rates. The attachment of knee and elbow joints is a significant improvement of the Bunster and Meyer technique. However, the procedure remains invasive thus maintenance of sterile conditions throughout the surgery is imperative. To further prevent infection of the surgical site, it is important that the parabiosed animals receive a combination of antibiotics and be monitored regularly. To ensure firm support and prev.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Isoflurane-Phoenix	Clipper	NDC 57319-559-06
Posi-Seal Induction Chamber	Molecular Imaging Products	AS-01-0530-SM
Portable Anesthesia System	Molecular Imaging Products	AS-01-0007
Gaymer T Pump	Gaymar Industries, Inc	TP650
Warming Blanket (Heating pad)	Kent Scientific Corp	TP-22G
Curved forceps	Roboz	RS-5101
Scissors	Fine Science Tools (FST)	FST 14063-09
Needle holder	FST	FST 12501-13
Electrical shaver	Oster	Golden A5