Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2008 Jul 11:7:4.
doi: 10.1186/1477-5751-7-4.

Multiple dosing strategies with acetyl L-carnitine (ALCAR) fail to alter age-related hearing loss in the Fischer 344/NHsd rat

Eric C Bielefeld  1 , Donald Coling, Guang-Di Chen, Donald Henderson
Affiliations

Multiple dosing strategies with acetyl L-carnitine (ALCAR) fail to alter age-related hearing loss in the Fischer 344/NHsd rat

Eric C Bielefeld et al. J Negat Results Biomed. .

Abstract

Background: The Fischer 344/NHsd rat undergoes age-related, progressive, high-frequency hearing loss beginning at age 12 months. The loss has been linked to defects/death in the outer hair cells related to oxidative stress originating in the mitochondria. Acetyl L-carnitine (ALCAR) is known to enhance mitochondrial bioenergetics and membrane efficiency. Therefore, ALCAR was targeted as a possible pharmacologic intervention to prevent, or even restore, hearing loss from aging.

Methods: Three different paradigms were used to deliver ALCAR to aging Fischer 344/NHsd rats. Rats in each condition had their hearing evaluated by auditory brainstem responses before, during, and after treatment. First, 24-month-old rats were given ALCAR (100 mg/kg dissolved 25 mg/ml in saline) by IP injection daily for one month. Second, 18-month-old rats were given ALCAR (100 mg/kg) by oral gavage for 90 days. Third, 15-month-old rats were given ALCAR (100 mg/kg) by oral gavage for 90 days. Control rats in each condition received saline by i.p. injection or gavage.

Results: Hearing thresholds of the three sets of ALCAR-treated animals were never significantly different from their matched controls before, during, or after the treatments at any of the five test stimuli (5, 10, 20, and 40 kHz tone bursts and a click).

Conclusion: The current study does not provide evidence that age-related hearing loss in the Fischer 344/NHsd rat can be altered with systemic administration of ALCAR.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Data from the study of F344/NHsd rats starting at 15 months of age. Mean ABR thresholds in response to 5, 10, 20, and 40 kHz tone burst stimuli, as well as a click stimulus are displayed for rats aged 15 (dark and open circle symbols) and 18 months (dark and open triangle symbols). 9 animals were treated for three months with ALCAR (dark circle and dark triangle symbols); 9 were treated with saline as controls (open circle and triangle symbols). Error bars are +/- 1 standard deviation.
Figure 2
Figure 2
Data from the study of F344/NHsd rats starting at 18 months of age. Mean ABR thresholds in response to 5, 10, 20, and 40 kHz tone burst stimuli, as well as a click stimulus are displayed for rats aged 18 (Top Panel), 21 months (Middle Panel), and 23 months (Bottom Panel). 9 animals were treated for three months with ALCAR (dark circle symbols); 9 were treated with saline as controls (open circle symbols). Error bars are +/- 1 standard deviation.
Figure 3
Figure 3
Data from the study of F344/NHsd rats starting at 24 months of age. Mean ABR thresholds in response to 5, 10, 20, and 40 kHz tone burst stimuli, as well as a click stimulus are displayed for rats aged 25 months. 4 animals were treated for one month from age 24 months to age 25 months with ALCAR (dark circle symbols); 4 were treated with saline as controls (open circle symbols). Error bars are +/- 1 standard deviation.
See this image and copyright information in PMC

References

    1. Rao GN, Boorman GA. History of the Fischer 344 rat. In: Boorman GA, Eustis SL, Elwell MR, Montgomery CA, MacKenzie WF, editor. Pathology of the Fischer rat: Reference and Atlas. San Diego, CA: Academic Press, Inc; 1990. pp. 5–8.
    1. Bielefeld EC, Coling D, Chen GD, Li MN, Tanaka C, Henderson D. Age-related changes in the auditory physiology of the Fischer 344 rat. Abstract in the 31st Midwinter Research Meeting of the Association for Research in Otolaryngology, Phoenix, AZ, Abstract #357. 2008.
    1. Staecker H, Zheng QY, Water TR Van De. Oxidative stress in aging in the C57B16/J mouse cochlea. Acta Otolaryngol. 2001;121:666–672. doi: 10.1080/00016480152583593. - DOI - PMC - PubMed
    1. Jiang H, Talaska AE, Schacht J, Sha SH. Oxidative imbalance in the aging inner ear. Neurobiol Aging. 2007;28:1605–1612. doi: 10.1016/j.neurobiolaging.2006.06.025. - DOI - PMC - PubMed
    1. Riva C, Donadieu E, Magnan J, Lavieille JP. Age-related hearing loss in CD/1 mice is associated to ROS formation and HIF target proteins up-regulation in the cochlea. Exp Gerontol. 2007;42:327–336. doi: 10.1016/j.exger.2006.10.014. - DOI - PubMed

Publication types

MeSH terms

Substances