Impact of maternal iron deficiency on the auditory functions in the young and adult guinea pig

Abstract

Objectives: The aim of this study was to evaluate the hearing function in the guinea pig offspring at post-natal day (PNd) 24 and PNd84 born from dams suffering from iron deficiency during pregnancy and lactation by using the auditory brainstem response (ABR).

Method: Female guinea pigs (n = 24 per dietary group) were fed an iron sufficient (IS) diet (114 mg/kg) or an iron deficient (ID) diet (11.7 mg/kg) during the gestation and lactation periods. Pups in both groups were weaned at PNd9 and given the IS diet. The hematocrit level was measured at every trimester of pregnancy and at the day of sacrifice in dams and at PNd24 and PNd84 in pups. The animal body weight was measured on every second day until the day of sacrifice. The ABR was used in pups to measure the hearing threshold using a broad range of stimulus intensities and latency at 100 and 80 dB in response to 2, 4, 8, 16, and 32 kHz tone pips at PNd24 and 84.

Results and discussion: No significant difference between dietary groups was measured in hearing threshold and absolute latencies in pups at PNd24 and PNd84. Although the ID offspring (n = 16) did not differ in brainstem transmission times (BTTs) at 80 dB compare to the IS siblings (n = 25) at PNd24, they showed significant delayed inter-peak latency (IPL) I-IV at 100 dB suggesting a delayed BTT. At PNd84, the latency of all peaks including IPL I-IV at 80 and 100 dB significantly decreased and was also similar in pups from both dietary groups suggesting a better brain maturation. This is the first study investigating the long-term impact of maternal iron deficiency on the auditory functions in the guinea pig offspring during early development to adulthood.

Keywords:

• Auditory brainstem response
• Threshold
• Latency
• Brainstem transmission times
• Offspring
• Maternal iron deficiency
• Hematocrit

Acknowledgements

N.S., M.E.S., S.F., and F.M.R. were involved in the experimental design; N.S. and M.T. conducted research; N.S. and S.F. performed statistical calculations; N.S. and S.F. analyzed the data; N.S. wrote the paper; and N.S., M.E.S., S.F., B.B., J.L.J., and F.M.R. contributed to the review and editing of the manuscript. F.M.R. participated in this protocol as the PI and supervisor of N.S. for her MSc. degree. All authors read and approved the final manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Sylvain Fiset http://orcid.org/0000-0002-9173-8304

Additional information

Funding

This research project was supported by a grant to F.M.R., S.F. and M.E.S. from the Canadian Institutes of Health Research (grant number#114908). M.E.S. was supported by the Canada Research Chairs program (grant number#950-209682) and by a New Brunswick Innovation Research Chair.