Surgical Technique for Superior Cervical Ganglionectomy in a Murine Model

Summary

The present protocol describes a mouse model of the ablation of adrenergic innervation by identifying and resecting the superior cervical ganglion.

Abstract

Growing evidence suggests that the sympathetic nervous system plays an important role in cancer progression. Adrenergic innervation regulates salivary gland secretion, circadian rhythm, macular degeneration, immune function, and cardiac physiology. Murine surgical sympathectomy is a method for studying the effects of adrenergic innervation by allowing for complete, unilateral adrenergic ablation while avoiding the need for repeated pharmacologic intervention and the associated side effects. However, surgical sympathectomy in mice is technically challenging because of the small size of the superior cervical ganglion. This study describes a surgical technique for reliably identifying and resecting the superior cervical ganglion to ablate the sympathetic nervous system. The successful identification and removal of the ganglion are validated by imaging the fluorescent sympathetic ganglia using a transgenic mouse, identifying post-resection Horner's syndrome, staining for adrenergic markers in the resected ganglia, and observing diminished adrenergic immunofluorescence in the target organs following sympathectomy. This model enables future studies of cancer progression as well as other physiological processes regulated by the sympathetic nervous system.

Introduction

Multiple studies have reported that the nerves in the tumor microenvironment play an active role in supporting tumor progression. The ablation of adrenergic sympathetic nerves has been shown to impair tumor development and dissemination in prostate and gastric cancer in vivo^1,2,3, while the pharmacological blockade of adrenergic receptors inhibits tumor growth in head and neck cancer⁴. Sympathetic neural involvement has also been described in pancreatic, cervical, and basal cell carcinoma progression^5,

Protocol

The animal procedures described here were approved by the Institutional Animal Care and Use Committee at the Memorial Sloan Kettering Cancer Center. Eight-week-old male and female NSG mice were used here. The animals were obtained from a commercial source (see Table of Materials). The instruments are sterilized, the surgical working surface is disinfected, the animal's skin surface is disinfected, and the surgeon wears sterile gloves throughout the procedure.

1. Preparation of the mice and preoperative setup

1. On the day before surgery, anesthetize the mouse with 2% isoflurane in an induction ....

Results

This protocol describes the surgical removal of the SCG in a mouse model. Figure 2 illustrates the anatomical landmarks, including the CCA, the anterior jugular vein, and the SCG. With dissection (Figure 2A), the right anterior jugular vein can be seen coursing alongside the lateral border of the trachea. As it is located deeper than the anterior jugular vein, the left CCA and its bifurcation into the internal carotid artery (ICA) and external carotid artery (EC.......

Discussion

This protocol describes a mouse model for the surgical unilateral ablation of SCG input. This technique allows for studying the effects of adrenergic innervation in various settings. In addition, the resected sympathetic ganglion can also be grown in 3D matrigel culture for in vitro experiments³⁰.

Studies involving SCGx have mostly been performed in rats, as their larger anatomy allows for easier anatomic visualization and dissection. While SCGx in mice has bee.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Anti-Tyrosine Hydroxylase Antibody	EMD Millipore	AB152
Artificial Tears Lubricant Ophthalmic Ointment	Akorn	59399-162-35
Curity 2 x 2 Inch Gauze Sponge 8 Ply, Sterile	Covidien	1806
Derf Needle Holder	Thomas Scientific	1177K00
Dissecting Microscope
Dumont #5/45 Forceps	Fine Science Tools	11251-35
Dumont #7b Forceps	Fine Science Tools	11270-20
ETHILON Nylon Suture	Ethicon	698H
Fine Scissors - ToughCut	Fine Science Tools	14058-09
Hypoallergenic Surgical Tape	3M Blenderm	70200419342
Induction Chamber, 2 Liter	VetEquip	941444
Isoflurane	Baxter	1001936060
Nair	Church & Dwight Co., Inc	40002957	chemical hair removing agent
NORADRENALINE RESEARCH ELISA	Labor Diagnostika Nord (Rocky Mountain Diagnostics)	BA E-5200
NSG Mouse	Jackson Laboratory	JAX:005557
Povidone-Iodine Swabstick	PDI	S41350
Webcol Alcohol Preps	Covidien	5110