Animal experiment:

Sixty-six male Sprague-Dawley rats (initial body weight 125-150 g, 5-6 weeks old) have free access to water and a regular diet, and are allowed 1 week of acclimation before the first treatment. The animals are divided randomly into one control group and seven experimental groups. Control group rats (n=10) are injected subcutaneously with an equal volume of vehicle (0.9% saline) for 10 days as those in the groups of kanamycin treatment, but without kanamycin. The experimental groups (n=56, 8 for each group: 1, 7, 14, 28, 56, 70 and 140 days after kanamycin administration, respectively) receive 500 mg of kanamycin sulfate/kg/day by subcutaneous injection for 10 days. The animal body weight is monitored every day and the injection dosage of kanamycin is adjusted accordingly. Auditory thresholds are tested by ABR. The tests are taken twice for each animal, first prior to the beginning of administration and then at different observing time points after kanamycin treatment. Details for the ABR measurement is described elsewhere.

Kanamycin sulfate is an aminoglycoside bacteriocidal antibiotic which acts by binding to the bacterial 30S ribosomes.
Kanamycin sulfate at the concentration above 0.0025% has a significant inhibition on the growth of B. bifidum and has no influence on the other four probiotics at incubation 12 h or 24 h. The optimum selective concentration of kanamycin sulfate in MRS media is 0.005% for selective enumeration of B.bifidum[3]
The neurons damage of the DCN caused by kanamycin (500 mg/kg/day) is reversible and autophagy is upregulated in the neurotoxic course of kanamycin on DCN through JNK1-mediated phosphorylation of Bcl-2 pathway in rats. The serum BUN and Cr levels are both increased at the 1st day after the period of kanamycin administration. The neurons expressing LC3 are increased at 1, 7 and 14 days after kanamycin administration in comparison to the control group. Kanamycin treatment results in the increase of autophagy in a time-dependent manner[1]. Kanamycin sulfate (5 mg/kg) and sodium ampicillin (10 mg/kg) administered intramuscularly (i.m.) separately, and then together, to five pony mares, and the ampicillin concentration exceeds 5 mg/mL in inflamed synovial fluid for some 2.5 h after injection, and kanamycin sulfate concentration exceeds 2 mg/mL for 7 h in the pony[2].
Reference:
[1]. Fan GR, et al. Reversible neurotoxicity of kanamycin on dorsal cochlear nucleus. Brain Res. 2013 Jan 17. pii: S0006-8993(13)00068-1.
[2]. Mohamed el SW, et al. Tongue actinomycetoma due to Actinomadura madurae: a rare clinical presentation. J Oral Maxillofac Surg. 2012 Nov;70(11):e622-4.
[3]. Guo WS, et al. Effect of Kanamycin Sulfate and Gentamicin on Growth of Probiotics. Advanced Materials Research,2011, 366, 490-493.
[4]. Firth EC, et al. Effect of induced synovial inflammation on pharmacokinetics and synovial concentration of sodium ampicillin and kanamycin sulfate after systemic administration in ponies. J Vet Pharmacol Ther. 1988 Mar;11(1):56-62.