New Insight into Potential Otoprotective Effects of Lactoferrin: Is It Paradoxically Ototoxic? An Experimental Investigation

Abstract

To evaluate the potential ototoxic effects of lactoferrin on the inner ear using electrophysiological and histological methods. METHODS: Thirty-two Sprague-Dawley rats (64 ears) were divided into four groups: control, saline, antiseptic solution (70% isopropyl alcohol + 2% chlorhexidine), and lactoferrin. Groups II-IV received three intratympanic injections. Auditory brainstem response (ABR) tests were performed at baseline, day 7, and day 21. Cochlear histology and VEGF immunoreactivity were assessed. RESULTS: Baseline hearing was similar across groups. Post-treatment, Groups II and IV showed partial recovery at 8, 16, and 24 kHz, while Groups III and IV had worsening thresholds at higher frequencies. Histologically, Group IV's cochlear structures remained largely intact. VEGF immunoreactivity was severe to moderate in Groups I, II, and IV, and weaker in Group III. CONCLUSIONS: Lactoferrin showed relative safety at lower frequencies but possible ototoxicity at higher frequencies. However, no significant structural damage was observed in cochlear tissues.