Flavanoid of Drynaria fortunei protects against gentamicin ototoxicity.
A flavanoid fraction (FF) from Drynaria fortunei, was investigated to see if it has the protective and ameliorative effects against gentamicin (GM) ototoxicity in guinea pigs (n = 36). Eleven (GM-group) animals received GM 100 mg/kg/day. Eleven (GMFF-group) animals received the same dose of GM but 2 days prior were dosed with FF (10 mg/kg/day) for 2 weeks. Seven (S-group) animals received saline and seven (FF-group) animals received the same dose of FF as the GMFF-group. The thresholds of tone-burst auditory evoked response (ABR) at 2 k, 8 k, and 32 k Hz were determined to be as follows: GM-group: 90 dB, 92 dB and 72 dB, GMFF-group: 30 dB, 37 dB and 38 dB, FF-group: 28 dB, 25 dB and 29 dB, S-group: 30 dB, 28 dB and 39 dB. The GM-group had a significantly higher hearing threshold than the other groups (p < 0.05). The GMFF- and FF-groups had hearing thresholds similar to the S-groups (p > 0.1). Repair of damaged hair cells was observed histologically. The percentage of the damaged outer hair cells (OHC) and inner hair cells (IHC) were determined to be as follows: GM-group: 43% and 20%, GMFF-group: 20% and 2%, FF-group: 9% and 2% and S-group: 4% and 1%. The GMFF-group showed less damage to the OHC (p > 0.05) and significantly less damage to the IHC (p < 0.05) than the GM-group. FF did not change the antimicrobial activity of GM and it did not show any intrinsic antibacterial effect. FF did not affect the kinetics of GM during the course of the experiment.
Department of Medicine, State University of New York at Stony Brook, NY 11794-8160, USA. mlong48@hotmail.com
Mian
M
Long
Eric E
EE
Smouha
Dan
D
Qiu
Fangrong
F
Li
Francis
F
Johnson
Benjamin
B
Luft
D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D004926:Escherichia coli / Q000187:drug effects; D016057:Evoked Potentials, Auditory, Brain Stem / Q000187:drug effects; D047309:Flavones / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D005839:Gentamicins; D006168:Guinea Pigs; D006199:Hair Cells, Auditory, Inner / Q000187:drug effects / Q000648:ultrastructure; D018072:Hair Cells, Auditory, Outer / Q000187:drug effects / Q000648:ultrastructure; D034381:Hearing Loss / Q000139:chemically induced / Q000517:prevention & control*; D008826:Microbial Sensitivity Tests; D009162:Mycobacterium avium / Q000187:drug effects; D008517:Phytotherapy; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D029621:Polypodiaceae
D000900:Anti-Bacterial Agents; D047309:Flavones; D005839:Gentamicins; D010936:Plant Extracts