Hyperpolarized 129Xe Lung MRI and Spectroscopy in Mechanically Ventilated Mice

Summary

Hyperpolarized xenon MRI can quantify regional lung microstructure (air-space dimensions) and physiology (ventilation and gas exchange) in translational research and clinical care. Although challenging, it can provide comparable pulmonary insights in preclinical studies. This protocol describes the infrastructure and procedures needed to perform routine xenon lung MRI in mice.

Abstract

Hyperpolarized (HP) xenon-129 (¹²⁹Xe) is an inhaled magnetic resonance imaging (MRI) contrast agent with unique spectral and physical properties that can be exploited to quantify pulmonary physiology, including ventilation, restricted diffusion (alveolar-airspace size), and gas exchange. In humans, it has been used to evaluate disease severity and progression in a variety of pulmonary disorders and is approved for clinical use in the United States and United Kingdom. Beyond its clinical applications, the ability of ¹²⁹Xe MRI to noninvasively assess pulmonary pathophysiology and provide spatially resolved information is valuable for preclinical research. Among animal models, mice are the most widely used due to the accessibility of genetically modified disease models. Here, ¹²⁹Xe MRI is promising as a minimally invasive, radiation-free, and sensitive technique to longitudinally monitor lung disease progression and therapy response (e.g., in drug discovery). This technique can extend to preclinical applications by incorporating an MRI-triggered, free-breathing apparatus or mechanical ventilator to deliver gas. Here, we describe the steps and provide checklists to ensure robust data collection and analysis, including creating a thermally polarized xenon gas phantom for quality control, optimizing polarization, animal handling (sedation, intubation, ventilation, and care for mice), and protocols for ventilation, restricted diffusion, and gas exchange data. While preclinical ¹²⁹Xe MRI can be applied in various animal models (e.g., rats, pigs, sheep), this protocol focuses on mice due to the challenges posed by their small anatomy, which are balanced by their affordability and the availability of many disease models.

Introduction

While pulmonary disorders remain the leading causes of global morbidity and mortality¹, the last decade has seen dramatic improvements in patient outcomes. These improvements are driven in part by two factors. Firstly, Phase III clinical trials now prioritize changes in lung function as endpoints rather than mortality, accelerating drug trials^2,3,4,5. Secondly, advancements in improved animal models have provided insights into disease mechanisms and aided therapy development^6,

Protocol

All methods described here were approved by the Institutional Animal Care and Use Committee (IACUC) of Cincinnati Children's Hospital Medical Center.

1. Initial site preparation

1. Create and test a thermally polarized ¹²⁹Xe gas phantom (Figure 3).
   1. Obtain a borosilicate glass vessel (~60 mL), a plunger valve with a front-sealing O-ring, and a ground borosilicate glass stem, all rated up to 150 psig. Ensure there.......

Discussion

Hyperpolarized ¹²⁹Xe MRI is emerging as a sophisticated and powerful technique to study lung microstructure and function in small animal models. This protocol is intended to guide initial site preparation and describe experimental procedures needed to quantify ventilation, diffusion, and gas exchange in mouse lungs with HP ¹²⁹Xe. Key prerequisites for experiments include establishing a ¹²⁹Xe gas phantom and ensuring high gas polarization is delivered to the animal. The latter requires car.......

Materials

Name	Company	Catalog Number	Comments
1 mL syringe	fisher scientific	Catalog No.14-955-464	https://www.fishersci.com/shop/products/sterile-syringes-single-use-12/14955464
10 mL graduated cylinder	Cole-Parmer	UX-34502-69	https://www.coleparmer.com/i/cole-parmer-essentials-graduated-cylinder-glass-hexagonal-base-10-ml-2-pk/3450269?PubID=UX&persist=true&ip=no& gad_source=1&gclid=CjwKCAi A6KWvBhAREiwAFPZM7h3do -ssjascARuVviKd7V7kC5ztdIB6 _70DnMr-K3qk9RKeJ7-IrhoCeT 0QAvD_BwE
18 G - veinous PFTE catheters (nonsterile)	Terumo Surflo	SROX1832CA	https://www.shopmedvet.com/product/iv-catheter-18-x-1-25inch?r=GSS17&p=GSS17&utm_source= google&utm_medium=google_ shopping&gad_source=1&gclid= CjwKCAiA0bWvBhBjEiwAtEsoW 4oTvZkAgWQCda6ocVtQlulVrG 2536FNbu5soMVSFN8xK_g1Uh pXIRoCGwoQAvD_BwE
20 G - veinous PFTE catheters (nonsterile)	Terumo Surflo	SROX2051CA	https://www.shopmedvet.com/product/iv-catheter-20-x-2inch?r=GSS17&p=GSS17&utm_source =google&utm_medium=google_ shopping&gad_source=1&gclid= CjwKCAiA0bWvBhBjEiwAtEsoW 87ggCkgToD_XF_UgpQBTpmN dgSNfCml6TkDKlW8k27Dq_daR itPuhoCnBQQAvD_BwE
22 G - veinous PFTE catheters (nonsterile)	Terumo Surflo	SROX2225CA	https://www.shopmedvet.com/product/iv-catheter-22-x-1inch?r=GSS17&p=GSS17&utm_source= google&utm_medium=google_ shopping&gad_source=1&gclid =CjwKCAiA0bWvBhBjEiwAtEso W9IM6mpee6m7e-lBfR8dZhSN KYbMUs7qgEU4gYCRTW_rJAs W_lGkthoCm30QAvD_BwE
400 mL tedlar bags	Jensen Inert Products	GST-001S-3507TJC	NA
60 mL syringe	fisher scientific	Catalog No.14-955-461	https://www.fishersci.com/shop/products/sterile-syringes-single-use-12/14955461
70% alcohol	Cole-Parmer	UX-80024-34	https://www.coleparmer.com/i/labchem-isopropyl-alcohol-70-v-v-500-ml/8002434?PubID=UX&persist=true&ip= no&gad_source=1&gclid=CjwKC AiA6KWvBhAREiwAFPZM7gGh p8g7MBHBBKadaRCAwfEMgV gna5fhYRsuXIuqoqOiToCC4fem nhoCGMEQAvD_BwE
Dewar for liquid nitrogen	Terra Universal	4LDB	https://www.laboratory-equipment.com/tw-4ldb-liquid-nitrogen-dewar-ic-biomedical.html?srsltid=AfmBOooxwMtOA1Z2TweR P8V5Iy5EvYT3alZuzoiY 3UF3Ib9RgFnDxVTfWP0
Eye lubricant	Refresh	REFRESH P.M.	https://www.refreshbrand.com/Products/refresh-pm
Fiber optic light	AmScope	HL250-AY	https://amscope.com/products/hl250-ay?tw_source=google &tw_adid=&tw_campaign= 16705014684&gad_source= 1&gclid=CjwKCAiA6KWvBhA REiwAFPZM7p-DpyvHJaGxR pAD1385hzGf1oPdKHHLFDR Sp8yrtxry11SNJeJnKxoCtAoQ AvD_BwE
Gaussmeter	Apex Magnets	GMHT201	https://www.apexmagnets.com/magnets/accessories/ht-digital-gaussmeter-with-peak-hold-can-display-gauss-or-tesla
Glass vessel (phantom)	Ace Glass	8648-24	https://aceglass.com/results.php?t=8648-24&t=8648-24
Heating pad	Office Depot	9206211	Pure Enrichment PureRelief Express Designer Series Heating Pad 12 x 15 Palm Aqua - Office Depot
Hyperpolarizer	Polarean	9820	https://polarean.com/xenon-mri-platform/
Intubation board	Hallowell EMC	000A3467	https://hallowell.com/product/rodent-tilting-workstand/
Intubation supplies	Parts list published elsewhere	NA	https://app.jove.com/t/50318/a-simple-method-of-mouse-lung-intubation
Isotopically enriched xenon cylinder	Linde Isotopes	XE-129(1%)N2(10%)HE CGMP 302SZ	NA
Liquid nitrogen	Linde	NI LC160-22	https://www.lindedirect.com/store/product-detail/nitrogen_n2_nitrogen_liquid _lc160_22_psi_ni_lc160_22 /ni-lc160-22?cat_id=shop&node=b89
Male slip luer	Cole-Parmer	UX-21943-27	https://www.coleparmer.com/i/diba-omnifit-t-series-solvent-waste-cap-adapter-polypropylene-male-luer-slip-x-1-16-id-hose-barb-5-pk/2194327
Manometer	Grainger	3T294	https://www.grainger.com/product/3T294?gucid=N:N:PS: Paid:GGL:CSM-2295:4P7A1P: 20501231&gad_source=1&gclid =CjwKCAiAi6uvBhADEiwAWiyR dltxrPJmmcm0bFiYLuPrB25HV QFdEfKMBqvgJBNdQUs3DZ7b TLr8CRoCanAQAvD_BwE& gclsrc=aw.ds
Minivent ventilator	harvard apparatus	73-0044	https://www.harvardapparatus.com/minivent-ventilator-for-mice-single-animal-volume-controlled-ventilators.html
Mouse ear puncher	fisher scientific	13-812-201	https://www.fishersci.com/shop/products/fisherbrand-animal-ear-tag-punch/13812201
Mouse tongue depressor	Medical Tools	VRI-617	https://medical-tools.com/shop/rodent-tongue-depressor.html
Mouse weight scale	Cole-Parmer	UX-11712-12	https://www.coleparmer.com/i/adam-equipment-cqt2000-core-portable-balance-2000g-x-1g-220-v/1171212?PubID=UX&persist=true&ip=no&gad _source=1&gclid=CjwKCAiA6K WvBhAREiwAFPZM7iYnAG5Ilc Z5DZWrdJ6wcLDZSCSfNJHOH m2PQOpyyWe0TjFa75R3tBoCjB sQAvD_BwE
MRI scanner	Bruker	7T Biospec horizontal system	https://www.bruker.com/de/products-and-solutions/preclinical-imaging/mri/biospec.html
Multimeter	Home Depot	1007898529	https://www.homedepot.com/p/Klein-Tools-600-Volt-Digital-Multi-Meter-Manual-Ranging-MM325/320822947
Natural abundance xenon	Linde Isotopes	UN 2036	NA
Needle	fisher scientific	305194	https://www.fishersci.com/shop/products/bd-general-use-precisionglide-hypodermic-needles-20/148266C?keyword=true
Needle safe syringe holder	fisher scientific	NC2703873	https://www.fishersci.com/shop/products/ndlsafe-ii-syr-uncap-deca/NC2703873#?keyword=needlesafe
Nitrogen cylinder	Linde	NI M-K	https://www.lindedirect.com/store/product-detail/nitrogen_n2_nitrogen_nf_k/ni-m-k?cat_id=shop&node=b89
Oxygen cylinder	Linde	OX M-K	https://www.lindedirect.com/store/product-detail/oxygen_o2_oxygen_usp_k/ox-m-k?cat_id=shop&node=b90
Oxygen sensor	Apogee instruments	MO-200	https://www.apogeeinstruments.com/mo-200-oxygen-sensor-with-handheld-meter/
Oxygen sensor inline flowhead	Apogee instruments	AO-002	https://www.apogeeinstruments.com/ao-002-oxygen-meter-sensor-flow-through-head/
PEEP valve	Hallowell EMC	000A6556A	https://hallowell.com/product/adjustable-peep-valve-with-exhaust-port-range-5-20cm-disposable/
Pipette tips	fisher scientific	Catalog No.02-707-108	Fisherbrand Stack-Rack Space-Saver Tips: 101-1000 L Standard; Blue; Volume: | Fisher Scientific
Plunger valve	Ace glass	8648-20	https://www.aceglass.com/results.php?t=8648
Preclinical coil	Doty scientific	custom built	https://dotynmr.com/products/bmax-xy-low-e/
Pressure regulators	Cole-Parmer	UX-98202-11	https://www.coleparmer.com/i/cole-parmer-single-stage-regulator-1500-scfh-capacity-346-cga-fitting/9820211?PubID=UX&persist=true&ip=no& gad_source=1&gclid=CjwKCAi A6KWvBhAREiwAFPZM7pruR xCAiaj52nA_8Y1nveQZRsD6B f0QO65o2DKFYqRoz0PopSkX QxoCxqcQAvD_BwE
Pressure-drop ventilator	Parts list published elsewhere	NA	https://sites.duke.edu/driehuyslab/resources/
PVC pipe for phantom	Home Depot	193682	https://www.homedepot.com/p/IPEX-1-2-in-x-10-ft-White-PVC-SCH-40-Potable-Pressure-Water-Pipe-30-05010HD/319692959
SAI animal heating system	SAII	Model 1030	https://i4sa.com/product/model-1030-monitoring-gating-system/
Saline	Farris Laboratories Inc.	0409488820-1	https://www.farrislabs.com/products/bacteriostatic-sodium-chloride-0-9-30ml-bottle?variant=42807174824167&currency =USD&utm_medium=product_ sync&utm_source=google&utm_ content=sag_organic&utm_ campaign=sag_organic&utm_ campaign=gs-2021-09-24&utm _source=google&utm_medium =smart_campaign&gad_source =1&gclid=CjwKCAiA6KWvBh AREiwAFPZM7oS3-hFDETO_2f6OWOoKyBMb WuDuWqYxdWRYUWEkY M2Py73VfGzVtRoC2FQQAvD_BwE
Sharps container	fisher scientific	22-730-455	https://www.fishersci.com/shop/products/sharps-container-47/p-7250579#?keyword=needle%20safe
Silicone epoxy	Grainger	3KMY7	https://www.grainger.com/product/3KMY7?gucid=N:N:PS:Paid:GGL:CSM- 2295:4P7A1P:20501231&gad_ source=1&gclid=CjwKCAiA6KW vBhAREiwAFPZM7voahkm8tda t1Euql1A8DFhC6AZVJ0wXzCE PfE6iUzrIJXV-Hl8o4xoCQLYQA vD_BwE&gclsrc=aw.ds
Silicone mold release lubricant	Grainger	19MW95	https://www.grainger.com/product/CRC-Mold-Release-Agent-16-oz-19MW95
Spirometer	ADInstruments	FE141	https://www.adinstruments.com/products/spirometer
Spirometer - mouse flowhead	ADInstruments	MLT1L	https://www.adinstruments.com/products/respiratory-flow-heads
Tubing - 1/4 OD	Clippard	URH1-0402-CLT-050	https://www.clippard.com/part/URH1-0402-CLT-050
Tubing - 1/8 OD	Clippard	URH1-0804-CLT-050	https://www.clippard.com/part/URH1-0402-CLT-050
Vacuum pump	Cole-Parmer	UX-60062-11	https://www.coleparmer.com/i/environmental-express-diaphragm-pump-high-volume-120v/6006211?PubID=UX&persist=true&ip=no&gad _source=1&gclid=CjwKCAiA6K WvBhAREiwAFPZM7uFGwmW pRelHNFgZVvJJV09vDUVyfyG HoKeZTiFNIiVTe-05IpJJPxoCO PoQAvD_BwE
Wire - 18 gauge	Digikey	2328-18H240-ND	https://www.digikey.com/en/products/detail/remington-industries/18H240/15202027?s=N4 IgjCBcoOwBxVAYygMwIYBsDOB TANCAPZQDa4YATPAGwgC6h ADgC5QgDKLATgJYB2AcxAB fQmAAMAFkqIQKSBhwFiZEA GZNATi0SGzNpE48BwsSErqw 6uQqV5CJSOQCsMF%2Bq11 GIVuy58QqLmss4gALbogvy4L AAEAO683LgMIkA
Xenon polarization measurement station	Polarean	NA	https://polarean.com/xenon-mri-platform/