Novel In Vivo Imaging Analysis of an Inner Ear Drug Delivery System in Mice

Comparison of Inner Ear Drug Concentrations over Time after Transtympanic and Systemic Injections

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12 Citations (Scopus)

Abstract

Objective: Systemic steroid injections are used to treat idiopathic sudden-onset sensorineural hearing loss (ISSHL) and some inner ear disorders. Recent studies show that transtympanic (TT) steroid injections are effective for treating ISSHL. As in vivo monitoring of drug delivery dynamics for inner ear is lacking, its time course and dispersion of drugs is unknown. Here, we used a new in vivo imaging system to monitor drug delivery in live mice and to compare drug concentrations over time after TT and systemic injections. Methods: Luciferin delivered into the inner ears of GFAP-Luc transgenic mice reacted with luciferase in GFAP-expressing cells in the cochlear spiral ganglion, resulting in photon bioluminescence. We used the Xenogen IVIS® imaging system to measure how long photons continued to be emitted in the inner ear after TT or systemic injections of luciferin, and then compared the associated drug dynamics. Results: The response to TT and IP injections differed significantly. Photons were detected five minutes after TT injection, peaking at ~20 minutes. By contrast, photons were first detected 30 minutes after i.p. injection. TT and i.p. drug delivery time differed considerably. With TT injections, photons were detected earlier than with IP injections. Photon bioluminescence also disappeared sooner. Delivery time varied with TT injections. Conclusions: We speculate that the drug might enter the Eustachian tube from the middle ear. We conclude that inner-ear drug concentration can be maintained longer if the two injection routes are combined. As the size of luciferin differs from that of therapeutics like dexamethasone, combining drugs with luciferin may advance our understanding of in vivo drug delivery dynamics in the inner ear.

Original languageEnglish
Article numbere48480
JournalPLoS One
Volume7
Issue number12
DOIs
Publication statusPublished - 2012 Dec 12

Fingerprint

drug delivery systems
Inner Ear
Drug Delivery Systems
ears
Photons
image analysis
injection
Drug delivery
Imaging techniques
drugs
Injections
mice
luciferin
Pharmaceutical Preparations
Bioluminescence
Audition
Imaging systems
Steroids
bioluminescence
Sensorineural Hearing Loss

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

@article{bf2fb158fbfa4b7ab4139c49a91aaffa,
title = "Novel In Vivo Imaging Analysis of an Inner Ear Drug Delivery System in Mice: Comparison of Inner Ear Drug Concentrations over Time after Transtympanic and Systemic Injections",
abstract = "Objective: Systemic steroid injections are used to treat idiopathic sudden-onset sensorineural hearing loss (ISSHL) and some inner ear disorders. Recent studies show that transtympanic (TT) steroid injections are effective for treating ISSHL. As in vivo monitoring of drug delivery dynamics for inner ear is lacking, its time course and dispersion of drugs is unknown. Here, we used a new in vivo imaging system to monitor drug delivery in live mice and to compare drug concentrations over time after TT and systemic injections. Methods: Luciferin delivered into the inner ears of GFAP-Luc transgenic mice reacted with luciferase in GFAP-expressing cells in the cochlear spiral ganglion, resulting in photon bioluminescence. We used the Xenogen IVIS{\circledR} imaging system to measure how long photons continued to be emitted in the inner ear after TT or systemic injections of luciferin, and then compared the associated drug dynamics. Results: The response to TT and IP injections differed significantly. Photons were detected five minutes after TT injection, peaking at ~20 minutes. By contrast, photons were first detected 30 minutes after i.p. injection. TT and i.p. drug delivery time differed considerably. With TT injections, photons were detected earlier than with IP injections. Photon bioluminescence also disappeared sooner. Delivery time varied with TT injections. Conclusions: We speculate that the drug might enter the Eustachian tube from the middle ear. We conclude that inner-ear drug concentration can be maintained longer if the two injection routes are combined. As the size of luciferin differs from that of therapeutics like dexamethasone, combining drugs with luciferin may advance our understanding of in vivo drug delivery dynamics in the inner ear.",
author = "Sho Kanzaki and Masato Fujioka and Akimasa Yasuda and Shinsuke Shibata and Masaya Nakamura and Okano, {Hirotaka James} and Kaoru Ogawa and Hideyuki Okano",
year = "2012",
month = "12",
day = "12",
doi = "10.1371/journal.pone.0048480",
language = "English",
volume = "7",
journal = "PLoS One",
issn = "1932-6203",
publisher = "Public Library of Science",
number = "12",

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T1 - Novel In Vivo Imaging Analysis of an Inner Ear Drug Delivery System in Mice

T2 - Comparison of Inner Ear Drug Concentrations over Time after Transtympanic and Systemic Injections

AU - Kanzaki, Sho

AU - Fujioka, Masato

AU - Yasuda, Akimasa

AU - Shibata, Shinsuke

AU - Nakamura, Masaya

AU - Okano, Hirotaka James

AU - Ogawa, Kaoru

AU - Okano, Hideyuki

PY - 2012/12/12

Y1 - 2012/12/12

N2 - Objective: Systemic steroid injections are used to treat idiopathic sudden-onset sensorineural hearing loss (ISSHL) and some inner ear disorders. Recent studies show that transtympanic (TT) steroid injections are effective for treating ISSHL. As in vivo monitoring of drug delivery dynamics for inner ear is lacking, its time course and dispersion of drugs is unknown. Here, we used a new in vivo imaging system to monitor drug delivery in live mice and to compare drug concentrations over time after TT and systemic injections. Methods: Luciferin delivered into the inner ears of GFAP-Luc transgenic mice reacted with luciferase in GFAP-expressing cells in the cochlear spiral ganglion, resulting in photon bioluminescence. We used the Xenogen IVIS® imaging system to measure how long photons continued to be emitted in the inner ear after TT or systemic injections of luciferin, and then compared the associated drug dynamics. Results: The response to TT and IP injections differed significantly. Photons were detected five minutes after TT injection, peaking at ~20 minutes. By contrast, photons were first detected 30 minutes after i.p. injection. TT and i.p. drug delivery time differed considerably. With TT injections, photons were detected earlier than with IP injections. Photon bioluminescence also disappeared sooner. Delivery time varied with TT injections. Conclusions: We speculate that the drug might enter the Eustachian tube from the middle ear. We conclude that inner-ear drug concentration can be maintained longer if the two injection routes are combined. As the size of luciferin differs from that of therapeutics like dexamethasone, combining drugs with luciferin may advance our understanding of in vivo drug delivery dynamics in the inner ear.

AB - Objective: Systemic steroid injections are used to treat idiopathic sudden-onset sensorineural hearing loss (ISSHL) and some inner ear disorders. Recent studies show that transtympanic (TT) steroid injections are effective for treating ISSHL. As in vivo monitoring of drug delivery dynamics for inner ear is lacking, its time course and dispersion of drugs is unknown. Here, we used a new in vivo imaging system to monitor drug delivery in live mice and to compare drug concentrations over time after TT and systemic injections. Methods: Luciferin delivered into the inner ears of GFAP-Luc transgenic mice reacted with luciferase in GFAP-expressing cells in the cochlear spiral ganglion, resulting in photon bioluminescence. We used the Xenogen IVIS® imaging system to measure how long photons continued to be emitted in the inner ear after TT or systemic injections of luciferin, and then compared the associated drug dynamics. Results: The response to TT and IP injections differed significantly. Photons were detected five minutes after TT injection, peaking at ~20 minutes. By contrast, photons were first detected 30 minutes after i.p. injection. TT and i.p. drug delivery time differed considerably. With TT injections, photons were detected earlier than with IP injections. Photon bioluminescence also disappeared sooner. Delivery time varied with TT injections. Conclusions: We speculate that the drug might enter the Eustachian tube from the middle ear. We conclude that inner-ear drug concentration can be maintained longer if the two injection routes are combined. As the size of luciferin differs from that of therapeutics like dexamethasone, combining drugs with luciferin may advance our understanding of in vivo drug delivery dynamics in the inner ear.

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