| Summary: | Objective To explore the hearing changes in an autism model mice [MeCP2-Tg1 mice, with overexpression of methyl-CpG binding protein 2 (MeCP2)] during development. Methods Three-chamber social test was used to assess the social ability of MeCP2-Tg1 mice and wild-type mice at 8 and 14 weeks after born. Auditory brainstem responses evoked by click and pure tone stimulus were recorded at 5 development nodes (4, 8, 12, 16 and 20 weeks) before and after the onset of abnormal social behaviors to assess hearing sensitivity (threshold), neural conduction velocity (latency) and response level (amplitude) in MeCP2-Tg1 mice at different developmental stages. Results ①Tg1 mice showed higher sensitivity to 24 kHz stimulus at 4 and 12 weeks (P < 0.05), and lower hearing threshold to 8 kHz stimulus at 20 weeks as compared with wild-type mice (P < 0.05), but the threshold reduction did not persist over the course of development. ②Tg1 mice had normal neural conduction velocity throughout development. ③ Compared with the wild-type mice, the amplitude of wave Ⅲ, which characterizes the superior olivary complex, was normal up to 8 weeks (inclusive) but showed a significant and persistent increase after 12 weeks (inclusive) (P < 0.05); the amplitude of wave V, which characterizes the auditory inferior colliculus, was significantly lower up to 8 weeks (inclusive) (P < 0.05) but showed normal after 12 weeks (inclusive). Conclusion The auditory brainstem responses of MeCP2-Tg1 mice are abnormal during development, mainly in the form of increased/decreased amplitude of responses to acoustic stimuli at different developmental periods, and the onset of hearing abnormalities precedes the onset of social behavior abnormalities.
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