Fig. 5.

Measurement of intracellular reactive oxygen species (ROS) production (DCFH-DA, green). (A) Control, (B) gentamicin (GM), (C) GM plus metformin, (D) vestibular cells were treated with 2.5 mM GM in the presence or absence of 1 mM metformin for 48 hours. Metformin significantly protected vestibular cells from GM-induced cytotoxicity, and ROS production in the GM-plus-metformin group was significantly lower than that in the GM and H₂O₂ groups (^**P<0.01, ^***P<0.001, respectively). However, ROS production was not significantly different between the control, metformin, an GM-plus-metformin groups (control, vestibular cells in control media; GM, cells treated with 2.5 mM GM for 48 hours; metformin, cells treated with 1 mM metformin; GM plus metformin, cells treated with 2.5 mM GM and 1 mM metformin for 48 hours; H₂O₂, 100 µM H₂O₂ was used as positive control). Results from 5 separate experiments in triplicate.