Figure 4.

E₂-replacement in female mice increases outer hair cell (OHC) survival in the base of the cochlea following a PTS-inducing noise exposure. (A) Experimental schematic. Female mice were gonadectomized at 8-weeks of age and treated with vehicle or E₂ (150 µg/kg) beginning 2-days after the gonadectomy for the remaining duration of the study. Animals were euthanized for tissue collection 1-week post-exposure. (B) E₂-replacement in female mice increases OHC survival in the base of the cochlea (45.2–55.0 kHz) 1-week following a PTS-inducing noise exposure (p < 0.0001). (C) E₂-replacement in female mice does not reduce the loss of paired IHC-ANF synapses 1-week following a PTS-inducing noise exposure. OHC survival and paired synapse number were compared between groups using a 2-way ANOVA followed by Sidak’s multiple comparison test. n = number of ears; plots: mean ± SD; **** p < 0.0001.