Med Lasers.  2022 Dec;11(4):236-243. 10.25289/ML.22.045.

Establishment of a non-invasive ischemic hearing loss animal model using the rose bengal dye and 532 nm low-level light energy (photo-thrombosis) in Republic of Korea: animal study

• Choi JH
• Choi JE
• Chang SY
• Lee MY
• Jung JY

• KMID: 2537597
• DOI: http://doi.org/10.25289/ML.22.045

Abstract

Background and Objectives
This research was designed to establish an animal model of cochlear ischemia using non-invasive photochemical reaction.
Materials and Methods
Rose bengal (RB) was administered to male Sprague-Dawley rats at 6 weeks of age through an intraperitoneal (IP) or intravenous (IV) injection. At five minutes after the RB injection, a 532 nm diode laser was used to irradiate the rats for 5, 10, and 15 minutes using a transcanal approach. The results of the auditory brainstem response at one, three, and seven days after the procedure were compared. On the 10th day, the cochleae were obtained to prepare tissue sections for pathohistological examination.
Results
For all the nine rats in the RB IP-injection group, hearing loss was not observed in any of the nine different conditions. For rats in the RB IV-injected group, hearing loss was not observed when 532 nm light was used for irradiation at 150 mW or 175 mW for 5 or 10 minutes. However, for rats irradiated for 15 minutes, hearing loss of more than 70 dB was observed at all frequencies one day later. Hearing loss of more than 50 dB persisted until 10 days later. Further pathohistological examinations of these rats revealed the destruction of the normal structure of the organ of Corti and stria vascularis.
Conclusion
The results of the present study demonstrate that the IV injection of RB with transcanal green light irradiation can induce cochlear ischemia in rats. This method could be useful for developing a model of cochlear ischemia.

Keyword

Cochlea; Ischemia; Photosensitizer; Rose bengal; Light