Objective To observe the effects of exposure to infrasound on auditory function of guinea pigs as reflected by the brain stem response (ABR) and distortion product otoaeoustic emission(DPOAE).Methods Seventy-two Guinea pigs were used in this study,of them,12 served as controls and 60 were divided into 2 experi- mental subgroups.ABR and DPOAE were detected after exposure to infrasound stimulation at 16 Hz,90 dB or 16 Hz,130 dB for 2 hours a day for 1 ,7,14,21 and 28 days.Results The threshold of ABR after exposed to infrasound at 16 Hz,90 dB in 1 day and 28 days was higher than the controls (P0.05),but significant difference was observed with 16 Hz 130 dB infrasound exposure on the 21st and,28th days when compared with the controls (P

Animals ; Endothelium, Vascular ; metabolism ; ultrastructure ; Environmental Exposure ; Male ; Rats ; Rats, Sprague-Dawley ; Sound ; Vascular Endothelial Growth Factor A ; metabolism

Objective To study the effect of infrasound on the changes of expression of NMDAR1 in hipp- ocampal cells.Methods Eighty-eight male Sprague-Dawley rats were randomized into eleven groups:control group,90 dB/1 d,7 d,14 d,21 d and 28 d infrasound exposed groups;130 dB/1 d,7 d,14 d,21 d and 28 d infra- sound exposed groups.All the animals in the test groups were put in an infrasound field with 8 Hz,90 dB or 130 dB for 2 hours daily.Immunohistochemistry methods were used to detect the changes of intracellular expression of NMDARI in hippocampal cells.Methods The expression of NMDAR1 in hippocampus after the rats were exposed to infrasound of 8 Hz,90 dB SPL showed a procedure from reducing on the 1st day to rising on the 7th and peaked on the 14th day,then to descending on 21st day and returning to the standard level on the 28th day.Exposure to infra- sound of 8 Hz,130 dB SPL induced opposite effects on the expression of NMDAR1 compared with 90 dB SPL,which showed a process of increasing,descending,reaching to the lowest,then ascending and returning to the normal.The lowest expression of NMDAR1 occurred on the 14th day in every observed hippocampal area.Conclusion 8 Hz, 90 dB/130 dB infrasound induced certain reversible reaction in the expression of NMDAR1 of hippoeampal cells in rats,which may disturb their learning and memory function.

ObjectiveTo study the effect of low-intensity millimeter wave(MMW)irradiation on the immune adhesion function of erythrocytes in mice with tumor.Methods60 healthy male mice were randomized into two groups:irradiation group(n=30) and control group(n=30).All mice were injected into abdominal cavity with A's abdominal juice cancer-cell(1×106/ml,0.2ml).MMW(36GHz,0.73-1.46mw/cm2)was used to irradiate the back of mice in irradiation group,once a day for 8 days.Control group received false irradiation using the same method.At 0d,3d,6d after irradiation, the erythrocytes were extracted from vein blood in the mice,and the RBC-C3b receptor rosettes rate(RCR),tumour-RBC rosette rate(TRR),RBC-SOD and RBC-LPO were determined.ResultsAt 3d after radiation,the RBC-C3b and TRR of irradiation group were higher than that of control group (P<0.01) and RBC-LPO was lower (P<0.05),while there was no significant difference on activity of RBC-SOD(P>0.05). there were no significant difference on all index between two groups at 0d and 6d(P>0.05).ConclusionsLow-intensity millimeter wave irradiation can improve the immune adhesion function of erythrocytes in mice with tumor.

Objective To observe the effects of infrasound(IS)of different frequencies and intensities on the pathological morphology of the gastric mucosa(GM)in rats.Methods One hundred and forty male Sprague- Dawley rats were randomly and evenly divided into a control group(group A),an 8 Hz 90 dB group(group B),an 8 Hz 130 dB group(group C)and a 16 Hz 130 dB group(group D).IS with these frequencies and intensities was administered daily for 2 h to all groups except group A,which received sham infrasound.The other 70 rats were ran- domly and evenly divided into a second control group(group E)and an exposure group(group F),in which the rats were continuously stimulated by IS at 8 Hz and 130 dB for 2 h a day for 14 d.The pathological morphology of the GM in each group was observed at 1 d,7 d,14 d,21 d and 28 d after IS exposure.Results①Compared with group A,GM lesion scores were significantly increased in groups B,C and D at 1 d,7 d,14 d,21 d and 28 d(P＜0.01),but not in group B at 1 d.②Compared with group B,the GM lesion scores in group C were obviously in- creased at 1 d,7 d,14 d,21 d and 28 d,while scores were also obviously improved in group C in comparison with those in group D at 14 d,21 d and 28 d(P＜0.01).③The GM lesion scores in group F decreased gradually after IS,but were still higher than those in group E at 1 d,7 d,14 d,21 d and 28 d after IS.④The ultrastructures of the chondrosome and endocytoplasmic reticulum in GM cells were deformed after 8 Hz and 16 Hz IS.Conclusion 8 Hz 90 dB,8 Hz 130 dB and 16 Hz 130 dB IS can all result in GM damage in rats.The injury severity was closely related to the frequency,intensity and duration of the IS.Rats can adapt to IS after several exposures,and the damage tends to recover automatically.

ObjectiveTo study the effect of 8 Hz infrasound on the expression of 5-hydroxytryptamine (5-HT) in rats' hippocampus and temporal cortex.Methods140 male SD rats were randomly divided into the control group, and experimental groups that exposed to infrasound of 8Hz,90dB,100dB and 130dB for 1,7,14,21,28,35,42 days. Experimental groups were exposed to infrasound for 2 hours each day. The control group was only placed in the infrasonic storehouse but without infrasound. Rats' brains were taken as soon as the exposure finished and strained by immunohistochemistry. The content of 5-HT in hippocampus and temporal cortex was detected under an optical microscope.ResultsInfrasound groups had less expression of 5-HT in hippocampus and temporal cortex than the control group (P<0.01), and the least were at the 28th day for 90 dB and 100 dB groups and the 21st day for 130 dB group. Then the expression of 5-HT had an increase in each group.ConclusionThe deceased expression of 5-HT in rats' hippocampus and temporal cortex could result from infrasound of 8 Hz. Rules of change are related to the parameter of infrasound and the 130 dB 8 Hz infrasound can induce greater changes compared with that of 100 dB and 90 dB.

OBJECTIVETo observe the changes of L929 cell membrane with atomic force microscope (AFM) after infrasound exposure and to explore the mechanisms of effect of infrasound on cell membrane.

METHODSAfter primary culture, the L929 cells were exposed to infrasound with intensity output of 130 dB and frequency of 16 Hz 2 hours each day for 3 days. The subsequent changes in the membrane of the control cells and the cells exposed to the infrasound were determined by nano-scale scanning with AFM.

RESULTSAfter infrasound exposure, the normal prominence of the membrane became short and the dent became shallow in the 7.5 microm x 7.5 microm and 4.0 microm x 4.0 microm photographs. The prominence appeared as cobblestones. The surface of the membrane became smooth.

CONCLUSIONThe membrane structure of the L929 cells can be changed by infrasound exposure with intensity of 130 dB and frequency of 16 Hz. The change might be one of the characteristics of effect of infrasound on cell membrane.

Animals ; Cell Membrane ; radiation effects ; ultrastructure ; Cells, Cultured ; Fibroblasts ; radiation effects ; ultrastructure ; Mice ; Microscopy, Atomic Force ; Sound ; adverse effects

AIMTo investigate the changes of several enzymes activities in the spleen and liver of rats after exposure to 8 Hz 130 dB infrasound for different time.

METHODSThirty-five male SD rats were randomly divided into five groups. Rats of group 1 served as control, rats from group 2 to 5 were exposed to 8 Hz 130 dB infrasound, 2 hours per day, for 1 wk, 2 wk, 3 wk, and 4 wk, respectively. The changes of enzymes activities in spleen and liver of rats were observed.

RESULTSMonoamine oxidase activities in spleen were significantly increased at 1 wk and 2 wk, it was decreased at 3 wk, and increased again at 4 wk (P < 0.05). There were no changes in the liver compared with the control group. Glutathione peroxides activities in spleen were significantly increased at 4 wk (P < 0.05) and it also increased in liver at 1 wk (P < 0.05). Superoxide dismutase activities in spleen were increased significantly from 1 wk to 4 wk, but there were no markedly changes in liver. The level of malondialdehyde in spleen were increased at 3 wk and 4 wk. In the liver, it were increased at 1 wk and 2 wk, and decreased at 3 wk, but it increased again at 4 wk (P < 0.05).

CONCLUSIONThe results indicated that lipid peroxidation and oxygen free radicals in spleen and liver were increased after infrasound exposure and it might induce the damage in tissue or cells.

Animals ; Environmental Exposure ; Glutathione Peroxidase ; metabolism ; Lipid Peroxidation ; Liver ; enzymology ; Male ; Malondialdehyde ; metabolism ; Monoamine Oxidase ; metabolism ; Noise ; Rats ; Rats, Sprague-Dawley ; Reactive Oxygen Species ; metabolism ; Spleen ; enzymology ; Superoxide Dismutase ; metabolism

OBJECTIVESTo investigate the effects of infrasound on ultrastructure of testis in mouse.

METHODSTwelve male BALB/C mice were randomly divided into three groups according to exposed duration on 1, 7 and 14 day. The mice were separately exposed to infrasound environment under 8 Hz/90 dB, 8 Hz/130 dB, 16 Hz/90 dB, 16 Hz/130 dB 2 hours per day. There was another control group which had three mice were separated into module with no infrasound. All the mice were killed on schedule. Then all the sections of testis were observed under electronic microscope. The alterations of structure and the chromatin were observed.

RESULTSSome acute alteration in one day group was found in testis cell, such as cellular denaturation and necrosis, intercellular edema, mitochondria swelling, liposome hyperplasia. When the infrasound was up to 8 Hz/130 dB, the damage showed seriously. In 7 and 14 day group, the acute alteration was gradually decreased. A plenty of abnormal sperm were found. And other alteration was chromatin condense. The effect of variational frequency was important in ultrastructure.

CONCLUSIONSThe infrasound markedly effected to testicular cell morphology and secreting function. Infrasound will lead to the alteration of procreation in mouse.

Animals ; Cell Size ; Male ; Mice ; Mice, Inbred BALB C ; Mitochondrial Swelling ; Sound ; adverse effects ; Testis ; secretion ; ultrastructure