Mouse Microsurgery Infusion Technique for Targeted Substance Delivery into the CNS via the Internal Carotid Artery

Summary

The present protocol describes a mouse microsurgery infusion technique, which effectively delivers substances directly into the brain via the internal carotid artery.

Abstract

Animal models of central nervous system (CNS) diseases and, consequently, blood-brain barrier disruption diseases, require the delivery of exogenous substances into the brain. These exogenous substances may induce injurious impact or constitute therapeutic strategy. The most common delivery methods of exogenous substances into the brain are based on systemic deliveries, such as subcutaneous or intravenous routes. Although commonly used, these approaches have several limitations, including low delivery efficacy into the brain. In contrast, surgical methods that locally deliver substances into the CNS are more specific and prevent the uptake of the exogenous substances by other organs. Several surgical methods for CNS delivery are available; however, they tend to be very traumatic. Here, we describe a mouse infusion microsurgery technique, which effectively delivers substances into the brain via the internal carotid artery, with minimal trauma and no interference with normal CNS functionality.

Introduction

In vivo models of central nervous system (CNS) diseases require an effective delivery of exogenous substances, such as drugs, pathogens, or exosomes, into the brain. Therefore, an ideal delivery method should cause minimal trauma to the animal, preserve the integrity of the neuronal network, and achieve high substance concentrations in the brain ¹.

Several surgical methods of local substance delivery have been described, including intra-sheath, intracerebral, and intraventricular injections or implants ^2,3,4,

Protocol

The procedures involved in the following protocol have been approved by the University of Miami Institutional Animal Care and Use Committee (IACUC). In addition, all procedures are being conducted in facilities approved by the Association for Assessment and Accreditation of Laboratory Animal Care International (AAALAC).

1. Preparation of Mice for Surgery

1. Anesthetize mouse with isoflurane mixed with oxygen, using a laboratory anesthesia system. Use isoflurane at setting between 4-5% and oxygen flow at 2 L/min on the commercial machine (See Materials Table). Transfer the animal to the surgery surface, under a stereomicroscope....

Results

The mouse infusion microsurgery technique described here is very versatile and has been used to deliver different substances directly into the brain, including the delivery of tumor cells in a representative model of brain metastasis formation ^1,12.

This technique is also suitable to assess the pathological aspects of different pathogens in the CNS. In a mouse model of H.......

Discussion

The infusion microsurgery described here has been proved to be very successful in delivering exogenous substances of various biological features into the CNS, preventing unwanted dissemination throughout the body ^1,12. Disruption of the blood-brain barrier is a pathological characteristic of several CNS-related diseases; therefore assessing the relationship of exogenous substances with the blood-brain barrier is of major importance and interest.

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Anesthesia instrument	Vetequip	901806
Surgical scissors	Fine Science Tool	14558-09
Surgical forceps straight tip	Fine Science Tool	00108-11
Surgical forceps angled tip	Fine Science Tool	00109-11
Spring scissors	Fine Science Tool	15000-08
Nylon suture	Braintree Scientific	SUT-S 104
Capillary tubing (Micro-Renathane 0.010” x 0.005” per ft.)	Braintree Scientific	MRE01050
Closing suture	VWR	95057-036
Isoflurane	Piramal
2,3,5-Triphenyltetrazolium chloride	FisherScientific	50-121-8005