ABSTRACT
Objective To observe the expression of the IGF-1 on the auditory cortex as well as the hippo-campus of rats which underwent longterm exposure to white noise to explore its effects for the repairment of the noise induced damage in the central nervous system.Methods 16 healthy Wistar rats were randomly grouped as chronic noise exposure group(group A)which underwent the longterm noise exposure(100 dB SPL white noise,4 hours per day for 28 days)and control group(group B).The expression of IGF-1 both on the auditory cortex and hippocampus was measured and the ABR waveforms were recorded.ResuIts Compared with the group A,the num-ber of IGF-1 positive neurons as well as the expression of IGF-1 both in the auditory cortex and the hippocampus of the group B increased(P<0.05),the ABR threshold was significantly higher(P<0.05 )after long-term noise exposure.ConcIusion Chronic noise exposure induced the changes of the IGF-1 system which may play a part in the protection for the noise-induced damage of the central nervous system.