The effects of infrasound on gastric emptying / 中华物理医学与康复杂志

ABSTRACT

Objective To explore the effects of infrasound frequency and intensity on gastric emptying in rats. Methods One hundred and forty rats were randomly divided into a control group, and groups receiving 8 Hz-90 dB, 8 Hz-130 dB and 16 Hz-130 dB infrasound. Another 70 rats were randomly divided into a control group and an exposure group continuously stimulated with infrasound at 8 Hz and 130 dB. The control group again was not exposed. The gastric emptying rate of the rats in all the groups was tested at different time points. Results ①Compared with the control group, gastric emptying rate decreased significantly after exposure to infrasound for 7 or 14 days. After exposure for 1 day, no significant difference was found. After exposure for 7 , 14, 21 or 28 days, gastric emptying decreased significantly more in the 8 Hz-130 dB group than in the 8 Hz-90 dB group or the control group. ②Compared with the controls, gastric emptying decreased in the 16 Hz-130 dB group after exposure for 1 , 7 and 14 days, but there was no significant difference between these two groups after 21 or 28 days. Gastric emptying decreased significantly more at 8 Hz-130 dB than at 16 Hz-130 dB after exposure for 14 or 28 days.③Gastric emptying tended to recover after exposure of 14 days to 8 Hz-130 dB infrasound, but compared with the controls, gastric emptying was still reduced after exposure had been stopped for 1 , 7 , 14, 21 and 28 days. Conclusion Infrasound at 8 Hz-90 dB, 8 Hz-130 dB or 16 Hz-130 dB can restrain stomach emptying. The extent of the reduction is closely related to the frequency, intensity and exposure time. Gastric emptying tends to recover after infra-sound exposure is stopped.