Abstract: ObjectiveTo investigate effects of 8Hz 90dB and 8Hz 130dB infrasound on hippocampi ultrastructure of SD rats.Methods60 male SD rats were randomly divided into the control group and experimental group. Rats of experimental group were exposed to 8Hz 90dB or 8Hz 130dB infrasound 2 hours every day for 1,7,14, 21,28,35 and 42 days. As soon as the exposure finished,the right hippocampus of rat was taken and examined by electron microscopy.ResultsHippocampus ultrastructure of rats was changed after only one day exposure to infrasound and the longer exposure to infrasound, the worse ultrastructure changed. But during the latter period,damages of hippocampus ultrastructure became lighter. Different rules were observed between 90dB and 130dB groups.ConclusionInfrasound of 8Hz 90dB and 8Hz 130dB can make hippocampus ultrastructure of rats damaged mainly as denaturalizations. These changes are nonliner with time, and the hippocampus of rats has adaptability to infrasound.

Key words: rat, hippocampus, ultrastructure, infrasound