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Sawamura S, Ogata G, Asai K, Razvina O, Ota T, Zhang Q, Madhurantakam S, Akiyama K, Ino D, Kanzaki S, Saiki T, Matsumoto Y, Moriyama M, Saijo Y, Horii A, Einaga Y, Hibino H. Analysis of Pharmacokinetics in the Cochlea of the Inner Ear. Front Pharmacol 2021; 12:633505. [PMID: 34012393 PMCID: PMC8128070 DOI: 10.3389/fphar.2021.633505] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 04/16/2021] [Indexed: 11/14/2022] Open
Abstract
Hearing loss affects >5% of the global population and therefore, has a great social and clinical impact. Sensorineural hearing loss, which can be caused by different factors, such as acoustic trauma, aging, and administration of certain classes of drugs, stems primarily from a dysfunction of the cochlea in the inner ear. Few therapeutic strategies against sensorineural hearing loss are available. To develop effective treatments for this disease, it is crucial to precisely determine the behavior of ototoxic and therapeutic agents in the microenvironment of the cochlea in live animals. Since the 1980s, a number of studies have addressed this issue by different methodologies. However, there is much less information on pharmacokinetics in the cochlea than that in other organs; the delay in ontological pharmacology is likely due to technical difficulties with accessing the cochlea, a tiny organ that is encased with a bony wall and has a fine and complicated internal structure. In this review, we not only summarize the observations and insights obtained in classic and recent studies on pharmacokinetics in the cochlea but also describe relevant analytical techniques, with their strengths, limitations, and prospects.
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Affiliation(s)
- Seishiro Sawamura
- Division of Glocal Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Genki Ogata
- Division of Glocal Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Kai Asai
- Department of Chemistry, Keio University, Yokohama, Japan
| | - Olga Razvina
- Department of Molecular Physiology, Niigata University School of Medicine, Niigata, Japan.,G-MedEx Office, Niigata University School of Medicine, Niigata, Japan
| | - Takeru Ota
- Division of Glocal Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Qi Zhang
- Division of Glocal Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan.,Department of Molecular Physiology, Niigata University School of Medicine, Niigata, Japan.,Department of Otolaryngology, Head and Neck Surgery Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Sasya Madhurantakam
- Division of Glocal Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Koei Akiyama
- Department of Molecular Physiology, Niigata University School of Medicine, Niigata, Japan
| | - Daisuke Ino
- Division of Glocal Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Sho Kanzaki
- Department of Otolaryngology, School of Medicine, Keio University, Tokyo, Japan
| | - Takuro Saiki
- Department of Medical Oncology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Yoshifumi Matsumoto
- Department of Medical Oncology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Masato Moriyama
- Department of Medical Oncology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Yasuo Saijo
- Department of Medical Oncology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Arata Horii
- Department of Otolaryngology, Head and Neck Surgery Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Yasuaki Einaga
- Department of Chemistry, Keio University, Yokohama, Japan
| | - Hiroshi Hibino
- Division of Glocal Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan.,AMED-CREST, AMED, Osaka, Japan
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Abstract
Ototoxic drugs can be used to produce a loss of cochlear hair cells to create animal models of deafness. However, to the best of our knowledge, there is no report on the establishment of a rat deafness model through the combined application of aminoglycosides and loop diuretics. The aim of this study was to use single or combined administration of furosemide and kanamycin sulfate to establish rat models of deafness. The rats received intravenous injections of different doses of furosemide and/or intramuscular injections of kanamycin sulfate. The auditory brainstem response was measured to determine the hearing threshold after drug application. Immunocytochemistry and confocal microscopy were performed to evaluate inner ear morphology. In the group receiving combined administration of furosemide and kanamycin, the auditory brainstem response threshold showed significant elevation 3 days after administration, higher than that produced by furosemide or kanamycin alone. The hair cells showed varying degrees of injury, from the apical turn to the basal turn of the cochlea and from the outer hair cells to the inner hair cells. The spiral ganglion cells maintained a normal morphology during the first week after the hair cells completely disappeared, and then gradually degenerated. After 2 months, the majority of spiral ganglion cells disappeared, but a few remained. These findings demonstrate that the combined administration of furosemide and kanamycin has a synergistic ototoxic effect, and that these drugs can produce hair cell loss and hearing loss in rats. These findings suggest that even in patients with severe deafness, electronic cochlear implants may partially restore hearing.
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Affiliation(s)
- Long Ma
- The Second Artillery General Hospital of Chinese PLA, Beijing, China
| | - Hai-Jin Yi
- Department of Otolaryngology-Head & Neck Surgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Fen-Qian Yuan
- Department of Head and Neck Surgery, Jiangxi Cancer Hospital, Nanchang, Jiangxi Province, China
| | - Wei-Wei Guo
- Department of Otolaryngology, Head & Neck Surgery, Institute of Otolaryngology, Chinese PLA General Hospital, Beijing, China
| | - Shi-Ming Yang
- Department of Otolaryngology, Head & Neck Surgery, Institute of Otolaryngology, Chinese PLA General Hospital, Beijing, China
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