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Ototoxicity of kanamycin in developing rats: Relationship with the onset of the auditory function
Hewing R ~ , 2 (1980) 111-113 Ehevier/North-HoHand Biomedic~dPress .
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OTOTOXICITY OF KANAMYCIN IN DEVELOPING RATS: RELATIONSHIP WITH TIH,~ ONSET OF THE AUDITORY FUNCTION
MICHELMAROT l,ALAINUZIEL ~ .and RAYMONDROMAND2 I i~bo~toire d'F,xplorations Neuro-Sensorielles, Oinique O.R.L. (Pr. Y. Guern'er), H6spital Saint.g~ktwles, 34059Monwdlier, and 2 Laboratoire de Neurophysiologie, /]mverszte " " " " des Sciences et Techniques du Languedoc, 34060 Montcpdlier, France
(Received 16 October 1979; accepted 6 November 1979)
In oraer to test the relationship between the ototoxicity of kanamycin and the onset of the auditory function, two groups of developing rats were intoxicated with kanamycin before and after ti~e period of onset of cochlear potentials (8th postnatal day). Kanamycin was shown to have a weak ototoxic effect before the 8th postnatal day and a strong ototoxic effect after ~his period. These results indicate a critical period of sensitivity to ototoxic antibiotic~ during auditory development. Key words: kanamycin;ototoxicity; c~chlear action potentials; development;rat.
INTRODUCTION The structural ototoxic effect of kanamycin during intrauterine life has already been shown in guinea pigs [1,3~9]. Our electrophysiological studies performed on guinea pigs [8,10] showed that kanamycin had an intrauterine ototoxic effect only when administrated during the last fifteen days of gestation. As the onset of cochlear potentials in guinea pigs occurs around the fifteenth day before the term of g~station [4], a relationship between the ototoxicity of kanamycin and the onset of ~he auditory function was assumed. In order to check this hypothesis, an experiment was designated in rats in which placental filtration cannot interfere with the results becaus ~. the onset of auditory function occurs during the second postnatal week [2,5]. MATERIALSAND METHODS Twelve litters of rats were used in this study. The animals were divided into two groups which were given respectively a daily intramuscular injection of kanamycin (400 mg/kg/day) for 8 days. In the first group (6 litters, 20 animals), the treatment w~s initiated from birth and continued until the 8th postnatal day (0-8th day group). In the second group (4 litters, 14 animals), the treatment was performed fi'om the 8th day to the 16th day (8th-16th day group). 10 nou-treated rats from two other litters were kept as controls. The animals were tested electrophysiologicaUy from the 3Oth day by recording the
112 compound action potential (APj from the round window. ARas elicited by clicks, thirdoctave filtered clicks (with center frequencies of 0.5, 1,2,4, 8 kHi) aa.d 16 kHz tone
bursts. Details of the procedure were given in a previous article [lo]. RESULTS The 20 animals treated during the 8 first postnatal days gave discrete evidence of
ototoxicity. Responses to clicks and mid-frequency faltered clicks (OS, 1, 2 and 4 k&j were practically unaltered with normal AP thresholds, amplitudes and latencies when compared with controls. Nevertheless 3 animals showed slightly elevated thresholds for 8 kHz filtered clicks and 1I animals showed a 20-40 dB thresholdshift for 16 kHz tote bursts when compared with controls (Fig. 1j. On the contrary, the 14 animals treated- during the period of the 8th to 16th postnatal day showed very severe alterations of action potentials. The mean threshold shift for clicks was about 80 dB over the controls thresholds and 85 dI5 for 8- and I6 kH.z filt.ered clicks (Fig. 1j. The amplitude-intensity curve showed a fast increase of the amplitude giving the recruiting function. The latencies of the AP lkrercshorter than in normal animals at high intensities. In many cases, the AP wavefcbrmwas altered and broad response could be noticed. In 5 animals, the hearing loss was so great that no AP could be elicited at 160 dB SBLwith 1the various stimuli.
FREQUENCY OF THE STIMULATION
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)
2 4 8 16 1 ...*..........**D*~~*~~~~~~~*~*~ **.......,.,.......***** l***....,_ -I b l******...,,.,..
. 0'5 l
l
20 30 40 50 60 70 tm 90 100 Fig 1 Mean threshold shifts relative to the normal mean thresholds in the 2 groups of kanamy&treated developing rats. A,rats treated from birth to the 8th postnatal da!{; q rats treated from the 8th to the 16th postnatal day;. . l1standard deviation of the control group. l
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113 DISCUSSION
The present study shows a strikirg difference between the we~k ototoxicity of kanamyein when the treatment is performed before the ~th postnatal 0ay and the strong ototoxie effect of this antibiotic after this period. Thi~ period of the second postnatal week Corresponds to the onset of cochlear potentials of the rat which has been found by the 8th-9th postnatal day for the cochlear microphonic [2,5] and by the 12th day for the action potential [5]. The confrontation of our resu!~.swith the period of the onset of cochlear potentials in rats confirms a relationship betw,~'en ototoxicity of kanamycin and the onset of the auditory function. In our previous studies performed on guinea pigs [8,10], cochlear p,3tentials were only affected when the treatment was initiated from the 15th c ay before biirth which corresponds to the period of the onset of the auditory function [4]. The ~.'e,~keffect obtained during the first 8 postr, ltal days of treatment may be explained by the strong doses used, the low clearance of the antibiotic in the labyrinthine :~uids [6,7] and the short lapse of time between the end of the treatment and the period of onset of cochlear potentials. Nevertheless, these data, taken together with those on guinea pigs indicate that a critical period of sensitivity to ototoxic antibietic~ can be found during auditory development. This period during which antibi.3tics begin to alter the cochlear function corresponds to the period of onset of the auditory function. ACKNOWLEDGEMENTS
This research was supported by grants from the I.N.S.E.R.M. (A.T.P. 21-75-44 and A.S.R. No. 6) and from the Fondation pour la Recherche M6dicale. REFERENCES
I11 Akiyoshi, M., Sate, K., Shoji, T., Sugahiro, K. and Tajima, T. (1974): Ototoxic effect of 3'#'dideoxykanamicyin B on the inner ear in the intrauterine guinea pig embryo~. Jap. J. Antibiotics 27,745. [21 Crowl~y, D.E. and Hepp-Reymond, M.C. (1966) Development of cochlear function in the ear of the infant rat. J. Comp. PhysioL Psychol. 62,427-432. 131 Mesolella, C. (1963): Ricerche sperimentalli sulla tossocita da Kanamieina sull' c recchio interne di carla durante la vita intrautefina. Arch. Int. Latyngol. 7t, 37-45. 141 Remand, R. (1971): Maturation des potentiels cochleaires ~ans la p~riod~ p6rimtale che7 le chat et chez le cobaye. J. Physiol. (Patio 63,763-782. 151 Remand, R. and Uziel, A. (1978): Maturation of cochlear potentials in the rzt and effect of kanamycin on the onset of the auditory function. Neurosci Abstr. 8.125 ~[61 Stupp, H., Rauch, S., Sous, H., Brun, J.P. and Lagler, F. (1967): Kanamycin dodge and levels in ear and other organs. Arch. Otolaryngol. 86,515-522. 171 Toyoda, Y. and Tachibana, H. (1978): Tissue levels of kanaraycin in correlation with ore- and nephrotoxicity. Acta Otolaryngol. 86, 9-14. I++l Uziel, A., Remand, R. and Gabrion, J. (1977): Intrauterine ototoxicity of kanamyci~ in the guinea pig. In: Inner Ear !Biology, pp. 347-358. Editors: M. Portmann and J.M. Aran. I.N.S.E.R.M., Paris. [~l Uziel, A., Gabrion, J. and Remand, R. (1979): Hair :ell degeneration in guinea pigs into×ieated with kanamyein during intrau refine life. Arch. Otolar3 ngol. 224, 187-191. Uziel, A., Remand, R. and Marot, M. (1979): Electlophysiological study of the ot~to×i¢ity of kanamycin during development in guinea pigs. Hearint: Res. 1,203-211.
;
.
.
.
•:
111
.
.
OTOTOXICITY OF KANAMYCIN IN DEVELOPING RATS: RELATIONSHIP WITH TIH,~ ONSET OF THE AUDITORY FUNCTION
MICHELMAROT l,ALAINUZIEL ~ .and RAYMONDROMAND2 I i~bo~toire d'F,xplorations Neuro-Sensorielles, Oinique O.R.L. (Pr. Y. Guern'er), H6spital Saint.g~ktwles, 34059Monwdlier, and 2 Laboratoire de Neurophysiologie, /]mverszte " " " " des Sciences et Techniques du Languedoc, 34060 Montcpdlier, France
(Received 16 October 1979; accepted 6 November 1979)
In oraer to test the relationship between the ototoxicity of kanamycin and the onset of the auditory function, two groups of developing rats were intoxicated with kanamycin before and after ti~e period of onset of cochlear potentials (8th postnatal day). Kanamycin was shown to have a weak ototoxic effect before the 8th postnatal day and a strong ototoxic effect after ~his period. These results indicate a critical period of sensitivity to ototoxic antibiotic~ during auditory development. Key words: kanamycin;ototoxicity; c~chlear action potentials; development;rat.
INTRODUCTION The structural ototoxic effect of kanamycin during intrauterine life has already been shown in guinea pigs [1,3~9]. Our electrophysiological studies performed on guinea pigs [8,10] showed that kanamycin had an intrauterine ototoxic effect only when administrated during the last fifteen days of gestation. As the onset of cochlear potentials in guinea pigs occurs around the fifteenth day before the term of g~station [4], a relationship between the ototoxicity of kanamycin and the onset of ~he auditory function was assumed. In order to check this hypothesis, an experiment was designated in rats in which placental filtration cannot interfere with the results becaus ~. the onset of auditory function occurs during the second postnatal week [2,5]. MATERIALSAND METHODS Twelve litters of rats were used in this study. The animals were divided into two groups which were given respectively a daily intramuscular injection of kanamycin (400 mg/kg/day) for 8 days. In the first group (6 litters, 20 animals), the treatment w~s initiated from birth and continued until the 8th postnatal day (0-8th day group). In the second group (4 litters, 14 animals), the treatment was performed fi'om the 8th day to the 16th day (8th-16th day group). 10 nou-treated rats from two other litters were kept as controls. The animals were tested electrophysiologicaUy from the 3Oth day by recording the
112 compound action potential (APj from the round window. ARas elicited by clicks, thirdoctave filtered clicks (with center frequencies of 0.5, 1,2,4, 8 kHi) aa.d 16 kHz tone
bursts. Details of the procedure were given in a previous article [lo]. RESULTS The 20 animals treated during the 8 first postnatal days gave discrete evidence of
ototoxicity. Responses to clicks and mid-frequency faltered clicks (OS, 1, 2 and 4 k&j were practically unaltered with normal AP thresholds, amplitudes and latencies when compared with controls. Nevertheless 3 animals showed slightly elevated thresholds for 8 kHz filtered clicks and 1I animals showed a 20-40 dB thresholdshift for 16 kHz tote bursts when compared with controls (Fig. 1j. On the contrary, the 14 animals treated- during the period of the 8th to 16th postnatal day showed very severe alterations of action potentials. The mean threshold shift for clicks was about 80 dB over the controls thresholds and 85 dI5 for 8- and I6 kH.z filt.ered clicks (Fig. 1j. The amplitude-intensity curve showed a fast increase of the amplitude giving the recruiting function. The latencies of the AP lkrercshorter than in normal animals at high intensities. In many cases, the AP wavefcbrmwas altered and broad response could be noticed. In 5 animals, the hearing loss was so great that no AP could be elicited at 160 dB SBLwith 1the various stimuli.
FREQUENCY OF THE STIMULATION
-10
0 10
i: kllz
)
2 4 8 16 1 ...*..........**D*~~*~~~~~~~*~*~ **.......,.,.......***** l***....,_ -I b l******...,,.,..
. 0'5 l
l
20 30 40 50 60 70 tm 90 100 Fig 1 Mean threshold shifts relative to the normal mean thresholds in the 2 groups of kanamy&treated developing rats. A,rats treated from birth to the 8th postnatal da!{; q rats treated from the 8th to the 16th postnatal day;. . l1standard deviation of the control group. l
l
l
l
113 DISCUSSION
The present study shows a strikirg difference between the we~k ototoxicity of kanamyein when the treatment is performed before the ~th postnatal 0ay and the strong ototoxie effect of this antibiotic after this period. Thi~ period of the second postnatal week Corresponds to the onset of cochlear potentials of the rat which has been found by the 8th-9th postnatal day for the cochlear microphonic [2,5] and by the 12th day for the action potential [5]. The confrontation of our resu!~.swith the period of the onset of cochlear potentials in rats confirms a relationship betw,~'en ototoxicity of kanamycin and the onset of the auditory function. In our previous studies performed on guinea pigs [8,10], cochlear p,3tentials were only affected when the treatment was initiated from the 15th c ay before biirth which corresponds to the period of the onset of the auditory function [4]. The ~.'e,~keffect obtained during the first 8 postr, ltal days of treatment may be explained by the strong doses used, the low clearance of the antibiotic in the labyrinthine :~uids [6,7] and the short lapse of time between the end of the treatment and the period of onset of cochlear potentials. Nevertheless, these data, taken together with those on guinea pigs indicate that a critical period of sensitivity to ototoxic antibietic~ can be found during auditory development. This period during which antibi.3tics begin to alter the cochlear function corresponds to the period of onset of the auditory function. ACKNOWLEDGEMENTS
This research was supported by grants from the I.N.S.E.R.M. (A.T.P. 21-75-44 and A.S.R. No. 6) and from the Fondation pour la Recherche M6dicale. REFERENCES
I11 Akiyoshi, M., Sate, K., Shoji, T., Sugahiro, K. and Tajima, T. (1974): Ototoxic effect of 3'#'dideoxykanamicyin B on the inner ear in the intrauterine guinea pig embryo~. Jap. J. Antibiotics 27,745. [21 Crowl~y, D.E. and Hepp-Reymond, M.C. (1966) Development of cochlear function in the ear of the infant rat. J. Comp. PhysioL Psychol. 62,427-432. 131 Mesolella, C. (1963): Ricerche sperimentalli sulla tossocita da Kanamieina sull' c recchio interne di carla durante la vita intrautefina. Arch. Int. Latyngol. 7t, 37-45. 141 Remand, R. (1971): Maturation des potentiels cochleaires ~ans la p~riod~ p6rimtale che7 le chat et chez le cobaye. J. Physiol. (Patio 63,763-782. 151 Remand, R. and Uziel, A. (1978): Maturation of cochlear potentials in the rzt and effect of kanamycin on the onset of the auditory function. Neurosci Abstr. 8.125 ~[61 Stupp, H., Rauch, S., Sous, H., Brun, J.P. and Lagler, F. (1967): Kanamycin dodge and levels in ear and other organs. Arch. Otolaryngol. 86,515-522. 171 Toyoda, Y. and Tachibana, H. (1978): Tissue levels of kanaraycin in correlation with ore- and nephrotoxicity. Acta Otolaryngol. 86, 9-14. I++l Uziel, A., Remand, R. and Gabrion, J. (1977): Intrauterine ototoxicity of kanamyci~ in the guinea pig. In: Inner Ear !Biology, pp. 347-358. Editors: M. Portmann and J.M. Aran. I.N.S.E.R.M., Paris. [~l Uziel, A., Gabrion, J. and Remand, R. (1979): Hair :ell degeneration in guinea pigs into×ieated with kanamyein during intrau refine life. Arch. Otolar3 ngol. 224, 187-191. Uziel, A., Remand, R. and Marot, M. (1979): Electlophysiological study of the ot~to×i¢ity of kanamycin during development in guinea pigs. Hearint: Res. 1,203-211.