不同频率、强度次声作用对大鼠胃排空功能的影响

The effects of infrasound on gastric emptying

目的探讨不同频率、强度次声对SD大鼠胃排空功能的影响。方法共有210只雄性SD 大鼠,将其中140只随机分成4组,分别为对照A组、8 Hz-90 dB组、8 Hz-130 dB组及16 Hz-130 dB组。各实验组大鼠每日于固定时间点置于次声舱内,给予不同频率、强度的次声作用,每天2 h,对照A组动物也置于次声舱内,每天2 h,期间不给予次声作用。每组分别于实验进行后第1,7,14,21及28天时各随机取出7只进行胃排空功能检测。另外剩下的70只大鼠则随机分为2组,分别为暴露组及对照B组;将暴露组大鼠置于次声舱内,给予8 Hz、130 dB的次声作用,每天2 h,连续暴露14 d后停止,分别于次声作用结束后第1,7,14,21及28天时各随机取出7只大鼠进行胃排空功能检测;对照B组大鼠则每天置于次声舱内 2 h,期间不给予次声作用。各组大鼠胃排空检测均在最后一次次声作用结束后1 h内进行。检测时,大鼠胃内灌注3 ml由99mTc标记的温盐水,于20 min后处死,采用发射型计算机断层扫描系统连续测量胃肠道残留的γ-射线量并计算出胃排空率。结果①大鼠经8 Hz、90 dB次声作用7 d和14 d后,其胃排空率明显低于对照A组(P<0．05)。大鼠经8 Hz、130 dB次声作用1 d后,其胃排空率与对照A组及8 Hz-90 dB组比较,差异均无统计学意义;但大鼠经该次声作用7,14,21及28 d后,其胃排空率则明显低于对照A组及 8 Hz-90 dB组(P<0．05)。②大鼠经16 Hz、130 dB次声作用1,7,14 d后,其胃排空率较对照A组明显降低;大鼠经该次声作用14 d和21 d后,发现其胃排空率明显高于8 Hz-130 dB组(P<0．01)。③大鼠经 8 Hz、130 dB次声作用2周后进行为期4周的后续效应观察,发现在第1,7,14,21及28天时,大鼠胃排空率逐渐恢复,但仍明显低于对照B组(P<0．05)。结论 8 Hz、90 dB或130dB以及16 Hz、130 dB次声作用均可引发大鼠胃排空功能障碍,其严重程度与次声频率、强度及作用时间相关;当停止次声作用后,大鼠胃排空功能有自我恢复的趋势。

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 infrasound exposure is stopped.