Abstract
To study the changes of blood-brain barrier (BBB) permeability and the heat shock protein 70(HSP70) after infrasonic damage, 40 SD rats were randomized into control, infrasonic damage 1 time, 7 times and 14 times groups. 8Hz 120dB Infrasound of 8Hz frequency and 120dB level was applied to the infrasonic damage groups for 2 hours once according to the planned schedule. The right frontal cortex was sampled for immunohistological examination. Under the electronic microscope changes of cerebral ultrastructure and BBB permeability were observed. Results showed that with the increase in the times of infrasonic damage, cerebral ultrastructure became more aggravated. The 1 and 7 times group shared the same changes of BBB permeability in which tight conjunction opened and Lanthanum nitrate particles passed BBB into the brain tissue. Moreover, the 14 times group has more radical changes in which a great deal of Lanthanum nitrate particles exist in the brain tissue (P<0.05). While, in 1 time group there is a weak positive HSP70 neuronal expression, the 7 and 14 times groups shared the same changes of strong HSP70 neuronal expression. It is concluded that infrasound can directly damage the function and structure of cerebral ultrastructure and BBB, and in the same degree, the extent of brain damage and positive HSP70 neuronal expression is closely related to the times of infrasonic injury. It is suggested that infrasound plays a pivotal role in brain damage which can in turn limit the expression of HSP70 through increasing BBB permeability.