Collagen and α‐Tubulin of Mouse Tympanic Membrane Fibroblasts Treated with Quinolones and Aminoglycosides

Abstract

Objective To assess collagen and α-tubulin levels of mouse tympanic membrane fibroblasts treated with quinolone and aminoglycoside antibiotics at concentrations found in eardrops. Study Design Prospective controlled cell culture study. Setting Academic tertiary medical center. Subjects Mouse tympanic membrane fibroblasts. Methods In experiment 1, fibroblasts were treated with the following for 24 or 48 hours: phosphate-buffered saline (negative control), dilute hydrochloric acid (positive control), 0.5% gatifloxacin, or commercially available 0.3% ciprofloxacin, 0.3% ciprofloxacin + 0.1% dexamethasone, 0.3% ofloxacin, 0.5% moxifloxacin, 0.3% gentamicin, or 3.5 mg/mL of neomycin + polymyxin B sulfate + hydrocortisone. In experiment 2, cells were treated with the pure form of gatifloxacin, gentamicin, ofloxacin, or ciprofloxacin. Cells were observed with phase-contrast microscope until harvested. Proteins were extracted for Western blotting with antibodies against collagen α1 type I (collagen 1A1) and α-tubulin, and for densitometry to quantify levels. Results Collagen and tubulin levels in fibroblasts treated with ofloxacin, moxifloxacin, gatifloxacin, or gentamicin for 24 hours were not different from the saline control. Fibroblasts treated with neomycin + polymyxin B + hydrocortisone, ciprofloxacin + dexamethasone, or ciprofloxacin for 24 hours had lower collagen 1A1 and α-tubulin levels (all P < .001) than the negative control. After 48 hours, fibroblasts treated with neomycin + polymyxin B sulfate + hydrocortisone, ciprofloxacin + dexamethasone, ciprofloxacin, or moxifloxacin had lower collagen 1A1 ( P ≤ .007) and α-tubulin ( P < .0001; except ciprofloxacin, P = .033) as compared with control. In experiment 2, only cells treated with ciprofloxacin had lower collagen 1A1 and α-tubulin levels and cell viability (all P < .0001) than control. Cytotoxicity assay and phase-contrast images mirrored the protein findings. Conclusion The adverse impact of topical antibiotic exposure on tympanic membrane collagen and tubulin protein levels is drug specific. This may be important for selection of ototopical therapy.

Appropriateness of Otic Quinolone Use among Privately Insured US Patients

“…[7][8][9][10][11] In addition, our group has published several studies that have linked otic quinolones to an increased risk of tympanic membrane perforation, thus altering the risk-benefit profile for treatment of otic conditions. [12][13][14][15][16][17][18] Given this new safety concern, the widespread use of otic quinolones, and the substantial time lag until new evidence changes clinical practice, 19 we aimed to understand how otic quinolones are being used and to identify potential opportunities to decrease utilization.…”

Effects of Common Ear Drops on Tympanic Membrane Healing in Rats

“…This is consistent with our earlier findings from tissue culture where cipro had decreased cell viability and markedly lower levels of collagen compared to ofloxacin. 13,14 Cipro has also been shown to decrease plasma antioxidant status to a greater extent than levofloxacin (an optical isomer of ofloxacin) and gatifloxacin, resulting in higher oxidative stress with ciprofloxacin. 18 The phototoxicity of cipro in humans has also been reported to be higher than that of ofloxacin.…”

Cytotoxicity of Ear Drop Excipients in Human and Mouse Tympanic Membrane Fibroblasts

“…The cytotoxicity of these “excipients” may have contributed to the toxicity that has previously been attributed to quinolones and steroids in commercial ear drops. 1-6…”