XNL is supported by Foundation for Angelman Syndrome Therapeutic (FAST) Postdoctoral Fellowship. YHJ is also support by FAST and NIH Grant R01HD110195 and R01MH117289.

The described procedures and protocols were in compliance with the guidelines outlined in the National Institutes of Health Guide for the Care and Use of Laboratory Animals. Additionally, the procedures received approval from the Animal Care and Use Committee at Yale University School of Medicine. Newborn wild-type (WT) C57BL/6J male and female mice were used for presented study. The animals were obtained from a commercial source (see Table of Materials).
1. Preparation ...

A Comprehensive Protocol for Delivering Intrathecal Injections in Neonatal Mice

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Described is a step-by-step procedure for intrathecal injection in neonatal mice (P1), resulting in widespread drug distribution in their brains. In comparison to the common intracerebroventricular injection method for delivering medication to neonatal mice, which involves piercing the cerebral cortex11, intrathecal injection avoids direct injury to the neonatal mouse brain due to needle penetration. Due to minimal invasiveness, intrathecal injection can be performed repeatedly when necessary, sim...

Intrathecal (IT) injection is a common clinical procedure used to administer medications, collect cerebrospinal fluid, and maintain intracranial pressure in both pediatric and adult patients in clinics1,2. The administration of medications via intrathecal injection is an effective approach for increasing medication concentrations in the central nervous system (CNS) while minimizing systemic exposure. Consequently, this method enhances therapeutic efficacy and reduces side effects, especially for temperature-sensitive and short half-life drugs3.
In preclinical studies testing new drugs and treatments using rodent models, it is imperative to employ a reliable method of drug administration that offers greater precision and result reproducibility4,5. For preclinical studies evaluating new treatments for neurogenetic and neurodevelopmental disorders, early treatment is crucial for initial proof-of-concept studies because earlier interventions are typically predicted to yield more favorable outcomes6,7,8.
Compared to conventional intracerebroventricular (ICV) injections, IT injections carry significantly lower risks since they obviate the need for direct penetration through the cerebral cortex. This advantage substantially reduces the potential damage to regional cortical tissue and surrounding nerves. Furthermore, IT injections allow for at least a fivefold increase in the administrable volume of medications through a single injection, greatly enhancing the feasibility of repeated administrations. However, due to the small size and fragile nature of newborn mice, performing intrathecal injections in newborn pups is technically challenging and requires specialized techniques, equipment, and meticulous handling.
This article provides a detailed protocol with step-by-step instructions for performing intrathecal injections in P1 newborn pups. The key considerations and good laboratory practices are emphasized here to ensure the consistency of administration and the safety and well-being of the animals during the procedure. By following this protocol, researchers can confidently conduct experiments with precision and reproducibility while minimizing any potential risks or discomfort to the animals.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Balance</td>
			<td>Ohaus Corporation</td>
			<td>30253017</td>
			<td></td>
		</tr>
		<tr>
			<td>C57BL/6J mice</td>
			<td>The Jackson Laboratory</td>
			<td>000664</td>
			<td></td>
		</tr>
		<tr>
			<td>Digital Microscope</td>
			<td>RWD</td>
			<td>DOM-1001</td>
			<td></td>
		</tr>
		<tr>
			<td>DPBS</td>
			<td>ThermoFisher</td>
			<td>14190144</td>
			<td></td>
		</tr>
		<tr>
			<td>Fast Green</td>
			<td>Sigma</td>
			<td>F7252-5G</td>
			<td></td>
		</tr>
		<tr>
			<td>Heating pad</td>
			<td>RWD</td>
			<td>69020</td>
			<td></td>
		</tr>
		<tr>
			<td>Needles</td>
			<td>Hamilton</td>
			<td>6PK (34/0.375&#8221;/4/12DEG)S</td>
			<td></td>
		</tr>
		<tr>
			<td>Syringe</td>
			<td>Hamilton</td>
			<td>1702RN</td>
			<td></td>
		</tr>
		<tr>
			<td>Syringe Filters</td>
			<td>Sigma</td>
			<td>SLGVM33RS</td>
			<td></td>
		</tr>
	</tbody>
</table>

intrathecal injection of newborn mouse for genome editing and drug delivery

Intrathecal injection is a commonly employed procedure in both pediatric and adult clinics, serving as an effective means to administer medications and treatments. By directly delivering medications and treatments into the cerebrospinal fluid of the central nervous system, this method achieves higher localized drug concentrations while reducing systemic side-effects compared to other routes such as intravenous, subcutaneous, or intramuscular injections. Its importance extends beyond clinical settings, as intrathecal injection plays a vital role in preclinical studies focused on treating neurogenetic disorders in rodents and other large animals, including non-human primates. However, despite its widespread application, intrathecal injection in young, particularly neonatal pups, poses significant technical challenges due to their small size and fragile nature. Successful and reliable administration of intrathecal injections in newborn mice requires meticulous attention to detail and careful consideration of various factors. Thus, there is a crucial need for a standardized protocol that not only provides instructions but also highlights key technical considerations and good laboratory practices to ensure procedural consistency, as well as the safety and welfare of the animals.
To address this unmet need, we present a detailed and comprehensive protocol for performing intrathecal injections specifically in newborn pups on postnatal day 1 (P1). By following the step-by-step instructions, researchers can confidently perform intrathecal injections in neonatal pups, enabling the accurate delivery of drugs, antisense oligos, and viruses for gene replacement or genome editing-based treatments. Furthermore, the importance of adhering to good laboratory practices is emphasized to maintain the well-being of animals and ensure reliable experimental outcomes. This protocol aims to address the technical challenges associated with intrathecal injections in neonatal mice, ultimately facilitating advances in the field of neurogenetic research that aims to develop potential therapeutic interventions.

Author Spotlight: Intrathecal Injection &#8211; An Efficient and Reliable Delivery Method to Test the Efficacy of Gene Editing in Neonatal Mouse Brains

Intrathecal Injection of Newborn Mouse for Genome Editing and Drug Delivery

Our group employs an interdisciplinary approach involving genomic discovery and functional modeling to study genetics and epigenetic basis of neurodevelopmental disorder. We perform molecular, neurophysiological, and neurobehavioral analysis using patient-induced pluripotent stem cell, or iPSC, in the mutant mice to dissecting the pathophysiology of neurodevelopmental disorder. We aim to develop a gene-editing-based treatment for this disease.Intracerebroventricular, also called ICV, injection is only method to directly deliver treatment to the central nervous system of neonatal mice. However, it has to penetrate through the cerebral cortex. The intrathecal, IT, injection is a commonly employed procedure in clinics, serving as an effective means to administer treatments directly into the central nervous system.However, intrathecal injection in neonatal pups can pose significant technical challenges due to their small size and fragile nature. We are trying to develop an efficient and reliable delivery method to test the efficacy and the gene editing in mouse brain that is non-viral and non-nanoparticle. Compared to conventional ICV injection, intrathecal injection presents a significantly lower risk, as it avoid the need for directly penetration through the cerebral cortex.This add advantage to minimize potential damage to regional cortical tissue and the surrounding nerves. Intrathecal injections also enable at least a fivefold increase in the administrable volume of medications through a single injection and greatly enhance the feasibility of repeated administrations.

Successful intrathecal injection immediately resulted in the widespread distribution of the administered solution, although the actual cellular penetration depended on the nature of the delivered drugs and materials. In this study, we used Fast Green to visualize the immediate results after intrathecal injection (IT) in wild-type neonates (Figure 1A-K) and compared it with conventional intracerebroventricular (ICV) injection (Figure 1L</...

Watch this Scientific Journal Video about Author Spotlight: Intrathecal Injection – An Efficient and Reliable Delivery Method to Test the Efficacy of Gene Editing in Neonatal Mouse Brains at JoVE.co

The present protocol outlines step-by-step instructions for performing intrathecal injections in neonatal mice for gene editing and drug delivery.

Intrathecal injection is a commonly employed procedure in both pediatric and adult clinics, serving as an effective means to administer medications and ...

intrathecal-injection-newborn-mouse-for-genome-editing-drug