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Solid lipid nanoparticles loaded with edaravone for inner ear protection after noise exposure.

Gao G, Liu Y, Zhou CH, Jiang P, Sun JJ - Chin. Med. J. (2015)

Bottom Line: Acoustic stress-induced ROS formation and edaravone exerted a protective effect on the cochlea.Comparisons of hearing thresholds and ROS changes in different animal groups showed that the threshold shift and ROS generation were significantly lower in treated animals than in those without treatment, especially in the edaravone SLN intratympanic injection group.Edaravone SLNs show noticeable slow-release effects and have certain protective effects against noise-induced hearing loss (NIHL).

View Article: PubMed Central - PubMed

Affiliation: Center for Otolaryngology of the People's Liberation Army, Naval General Hospital, Beijing 100048, China.

ABSTRACT

Background: Antioxidants and the duration of treatment after noise exposure on hearing recovery are important. We investigated the protective effects of an antioxidant substance, edaravone, and its slow-release dosage form, edaravone solid lipid nanoparticles (SLNs), in steady noise-exposed guinea pigs.

Methods: SLNs loaded with edaravone were produced by an ultrasound technique. Edaravone solution or edaravone SLNs were administered by intratympanic or intravenous injection after the 1 st day of noise exposure. Guinea pigs were exposed to 110 dB sound pressure level (SPL) noise, centered at 0.25-4.0 kHz, for 4 days at 2 h/d. After noise exposure, the guinea pigs underwent auditory brainstem response (ABR) threshold measurements, reactive oxygen species (ROS) were detected in their cochleas with electron spin resonance (ESR), and outer hair cells (OHCs) were counted with silvernitrate (AgNO 3 ) staining at 1, 4, and 6 days.

Results: The ultrasound technique was able to prepare adequate edaravone SLNs with a mean particle size of 93.6 nm and entrapment efficiency of 76.7%. Acoustic stress-induced ROS formation and edaravone exerted a protective effect on the cochlea. Comparisons of hearing thresholds and ROS changes in different animal groups showed that the threshold shift and ROS generation were significantly lower in treated animals than in those without treatment, especially in the edaravone SLN intratympanic injection group.

Conclusions: Edaravone SLNs show noticeable slow-release effects and have certain protective effects against noise-induced hearing loss (NIHL).

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Related in: MedlinePlus

ROS spectra of the five animal groups shown in (a) ROS spectra of normal animals’ cochleas. (b-d) ROS spectra of animals at 1, 4, and 6 days after noise exposure. (e) ROS spectra of animals at 1 day after EDA solution (iv). (f) ROS spectra of animals at 1 day after EDA solution (it). (g) ROS spectra of animals at 6 days after EDA SLNs (iv). (h, i) ROS spectra of animals at 1 and 6 days after EDA SLNs (it). ROS = Reactive oxygen species.
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Figure 2: ROS spectra of the five animal groups shown in (a) ROS spectra of normal animals’ cochleas. (b-d) ROS spectra of animals at 1, 4, and 6 days after noise exposure. (e) ROS spectra of animals at 1 day after EDA solution (iv). (f) ROS spectra of animals at 1 day after EDA solution (it). (g) ROS spectra of animals at 6 days after EDA SLNs (iv). (h, i) ROS spectra of animals at 1 and 6 days after EDA SLNs (it). ROS = Reactive oxygen species.

Mentions: The ESR spectrum of guinea pig cochleas had three main peaks, peak I (e ES II((e E and III (d E [Figure 2]. Peak I was a background peak of resonance, which appeared in all of the specimens for reasons that are unclear, not only in the cochleas,[29] but also in all of the other tissues[30] of animals without peaks found in this site. Peak II was called peak O∥, peak III was called peak O⊥. We could not define the ROS value from peak III precisely because peak coenzyme Q was mixed with this peak, so we choose peak II as the measurement peak to calculate the value of free radicals. We adopted h (cm) to represent the absolute value of ROS, which was calculated by the distance from the crest of the peak to the basal line, and we adopted w (g) to represent the weight of the cochlea, so we represented the relative value of ROS as ΔROS. Thus, ΔROS = h/w (cm/g). The changes in the ΔROS of the cochleas of the five groups are shown in Figure 3.


Solid lipid nanoparticles loaded with edaravone for inner ear protection after noise exposure.

Gao G, Liu Y, Zhou CH, Jiang P, Sun JJ - Chin. Med. J. (2015)

ROS spectra of the five animal groups shown in (a) ROS spectra of normal animals’ cochleas. (b-d) ROS spectra of animals at 1, 4, and 6 days after noise exposure. (e) ROS spectra of animals at 1 day after EDA solution (iv). (f) ROS spectra of animals at 1 day after EDA solution (it). (g) ROS spectra of animals at 6 days after EDA SLNs (iv). (h, i) ROS spectra of animals at 1 and 6 days after EDA SLNs (it). ROS = Reactive oxygen species.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4837839&req=5

Figure 2: ROS spectra of the five animal groups shown in (a) ROS spectra of normal animals’ cochleas. (b-d) ROS spectra of animals at 1, 4, and 6 days after noise exposure. (e) ROS spectra of animals at 1 day after EDA solution (iv). (f) ROS spectra of animals at 1 day after EDA solution (it). (g) ROS spectra of animals at 6 days after EDA SLNs (iv). (h, i) ROS spectra of animals at 1 and 6 days after EDA SLNs (it). ROS = Reactive oxygen species.
Mentions: The ESR spectrum of guinea pig cochleas had three main peaks, peak I (e ES II((e E and III (d E [Figure 2]. Peak I was a background peak of resonance, which appeared in all of the specimens for reasons that are unclear, not only in the cochleas,[29] but also in all of the other tissues[30] of animals without peaks found in this site. Peak II was called peak O∥, peak III was called peak O⊥. We could not define the ROS value from peak III precisely because peak coenzyme Q was mixed with this peak, so we choose peak II as the measurement peak to calculate the value of free radicals. We adopted h (cm) to represent the absolute value of ROS, which was calculated by the distance from the crest of the peak to the basal line, and we adopted w (g) to represent the weight of the cochlea, so we represented the relative value of ROS as ΔROS. Thus, ΔROS = h/w (cm/g). The changes in the ΔROS of the cochleas of the five groups are shown in Figure 3.

Bottom Line: Acoustic stress-induced ROS formation and edaravone exerted a protective effect on the cochlea.Comparisons of hearing thresholds and ROS changes in different animal groups showed that the threshold shift and ROS generation were significantly lower in treated animals than in those without treatment, especially in the edaravone SLN intratympanic injection group.Edaravone SLNs show noticeable slow-release effects and have certain protective effects against noise-induced hearing loss (NIHL).

View Article: PubMed Central - PubMed

Affiliation: Center for Otolaryngology of the People's Liberation Army, Naval General Hospital, Beijing 100048, China.

ABSTRACT

Background: Antioxidants and the duration of treatment after noise exposure on hearing recovery are important. We investigated the protective effects of an antioxidant substance, edaravone, and its slow-release dosage form, edaravone solid lipid nanoparticles (SLNs), in steady noise-exposed guinea pigs.

Methods: SLNs loaded with edaravone were produced by an ultrasound technique. Edaravone solution or edaravone SLNs were administered by intratympanic or intravenous injection after the 1 st day of noise exposure. Guinea pigs were exposed to 110 dB sound pressure level (SPL) noise, centered at 0.25-4.0 kHz, for 4 days at 2 h/d. After noise exposure, the guinea pigs underwent auditory brainstem response (ABR) threshold measurements, reactive oxygen species (ROS) were detected in their cochleas with electron spin resonance (ESR), and outer hair cells (OHCs) were counted with silvernitrate (AgNO 3 ) staining at 1, 4, and 6 days.

Results: The ultrasound technique was able to prepare adequate edaravone SLNs with a mean particle size of 93.6 nm and entrapment efficiency of 76.7%. Acoustic stress-induced ROS formation and edaravone exerted a protective effect on the cochlea. Comparisons of hearing thresholds and ROS changes in different animal groups showed that the threshold shift and ROS generation were significantly lower in treated animals than in those without treatment, especially in the edaravone SLN intratympanic injection group.

Conclusions: Edaravone SLNs show noticeable slow-release effects and have certain protective effects against noise-induced hearing loss (NIHL).

Show MeSH
Related in: MedlinePlus