Background Co-exposure to noise and microwave radiation occurs frequently. The central nervous system has been identified as a sensitive target organ for both noise and microwave exposure individually, and the underlying mechanisms remain poorly understood. The specific biological effects resulting from co-exposure to these two factors have yet to be fully elucidated. Objective To clarify the effects of co-exposure to noise and microwave on neurobehavior and hippocampal tissue structure, and to explore the underlying mechanism through the assessment of serum cytokines. Methods C57BL/6N mice were selected and randomly assigned to a blank control group, a noise group, a microwave group, and a combined noise & microwave exposure group. To establish the exposure models, the noise group was subjected to broadband noise at 100 dB for 2 h, while the microwave group received radiation at a central frequency of 9.375 GHz with an average power density of 12 mW·cm⁻² and a specific absorption rate of 2.58 W·kg⁻¹ for 15 min. Open field and tail suspension tests assessed anxiety-like emotional behaviour; novel object recognition and Y-maze tests evaluated cognitive function. Histological changes in hippocampal tissue were examined using haematoxylin and eosin (HE) staining, and Nissl staining under light microscopy. Serum cytokine levels were measured using radioimmunoassay and enzyme-linked immunosorbent assay (ELISA). Results After 3 d of exposure, the noise, microwave, and combined exposure groups showed significant reductions in exploration frequency, duration, and distance within the central zone of the open field test compared to the control group (P < 0.01); the combined exposure group exhibited increased ratios of peripheral-to-central exploration time and distance (P < 0.05). After 7 d of exposure, compared with the control group, the noise group maintained a decrease in central zone exploration time (P < 0.01), while the combined exposure group showed persistent decline across all central zone metrics (P < 0.05) and elevated peripheral-to-central ratios (P < 0.05); compared to the microwave group, the combined exposure group showed significant less time in the central zone (P < 0.05) and higher peripheral-to-central ratios (P < 0.05). Regarding behaviour and cognition, compared with the control group, the combined exposure group showed increased immobility time in the tail suspension test after 3 d of exposure (P < 0.01). At this interval, all exposure groups demonstrated reduced frequency and duration of novel object recognition (P < 0.05), with the combined exposure group showing a marked decrease in novel arm exploration time (P < 0.01). After 7 d of exposure, compared with the control group, the noise group showed reduced novel object recognition frequency (P < 0.05), and both the noise and microwave groups exhibited decreased novel arm exploration time (P < 0.05). Pathological alterations including an increased number of hyperchromatic nuclei and depleted Nissl bodies were observed in the CA3 and DG regions across all exposure groups with the most severe lesions observed in the combined exposure group. Serum levels of central nervous system-specific protein β (S-100β), glial fibrillary acidic protein (GFAP), and corticosterone (CORT) were significantly elevated in all exposure groups compared with the control group (P < 0.05). Aquaporin-4 (AQP4) levels increased in the combined exposure group (P < 0.05), while CXC chemokine ligand 10 (CXCL10) levels rose in both the noise and combined groups compared with the control group (P < 0.05). Specifically, S-100β and CXCL10 levels in the combined exposure group were higher than those in the microwave group (P < 0.05); moreover, levels of S-100β, GFAP, CORT, AQP4, and CXCL10 in the combined exposure group were significantly higher than those in the noise group (P < 0.05). Conclusion Combined exposure to noise and microwave radiation induces pathological changes in the hippocampus of mice, increases levels of serum stress hormones and neuro-specific biomarkers. These impairments are more severe than those observed following single-factor exposure. The underlaying mechanism may be related to systemic stress response, neuronal damage, astrocyte activation, and changes in blood-brain barrier permeability, leading to emotional behavioral abnormalities and cognitive decline.

Objective To investigate the functional changes of oligodendrocytes in a mouse model of cognitive impairment induced by microwave radiation and the mechanism.Methods C57BL/6N male mice were exposed to S-band microwave at 2.856 GHz and 8 mW/cm2 for 15 min.The rectal temperature of mice was monitored by an optical fiber thermometer during microwave radiation.The changes of autonomous exploration behavior and learning and memory ability of mice on the 1st and 7th days after microwave radiation were detected via the open field test and novel object recognition test.Immunofluorescence was used to detect the expression and distribution of neuroglia-2 proteoglycan(NG2)and myelin basic protein(MBP)in the hippocampus of mice on the 1st and 7th days after radiation.Clemastine fumarate,a drug that promoted the maturation of oligodendrocyte precursor cells was administered by gavage,and the expression levels of brain-derived neurotrophic factor(BDNF)and fibroblast growth factor 2(FGF2)in hippocampal tissues were detected by radioimmunoassay at 1 and 7 days after radiation.The changes of myelin sheath structure an 1 and 7 days after radiation were observed by transmission electron microscopy.The effects of clemastine fumarate on learning and memory impairment induced by microwave exposure in mice were assessed via open field and new object recognition experiments.Results Under the experimental conditions,the rectal temperature in mice caused by microwave radiation increased by less than 1 ℃,which was within the thermal safety range of the body.The open field test showed that compared with the control group,the microwave radiation group didn't change significant in terms of movement speedon the 1st and 7th days,but the time spent exploring in the central area was significantly reducedon the 1st day after radiation(P＜0.05).In the novel object recognition test,the indexes of the mice on the 1st day were significantly reduced(P＜0.05),indicating that the anxiety like behavior and cognitive function of the mice were impaired after microwave radiation.Compared with the control group,the proportion of NG2+area in the hippocampus was significantly decreased(P＜0.05)in the microwave radiation group,while that of MBP+area hardly changed on the 1st day after microwave radiation(P＞0.05).The expression level of oligodendrocyte related BDNF in the hippocampus was significantly decreased(P＜0.05).The myelin of the corpus callosum was broken,and the myelin g ratio was significantly increased(P＜0.05),suggesting that micro wave radiation could reduce the number of oligodendrocyte precursors and damage the secretion and myelin function of oligodendrocyte.Compared with the radiation group,the expression levels of BNDF and FGF2 in the radiation combined with clemastine fumarate group were up-regulated,the myelin g ratio was significantly decreased on the 1st day after radiation(P＜0.05),and the novel object recognition index was significantly increased(P＜0.05).Conclusion Pulsed microwave radiation below the body's fever threshold can cause cognitive dysfunction and other brain damage in mice.The impaired secretion and myelin function of oligodendrocytes and the decreased self-repair ability are the important mechanisms of cognitive dysfunction induced by microwave radiation.

Objective To investigate the effects of long-term radiofrequency(RF)radiation at 2.65 GHz on behavior,inflammatory response,and intestinal microecology in mice in order to provide a basis for the safety assessment of long-term RF exposure.Methods One hundred and eight male C57BL/6N mice(17～21 g,6～8 weeks old)were randomly assigned to a control group(Con)and a RF exposure group.The mice of the RF exposure group were subjected to whole-body uniform exposure to 2.65 GHz RF radiation in an electromagnetic reverberation chamber for 3 h/day for 28 consecutive days.RF field distribution and changes in core body temperature were monitored using an electromagnetic radiation analyzer and a fiber-optic temperature probe,respectively.Cognitive function was assessed using the Y-maze and novel object recognition(NOR)test.Anxiety-like behaviors were evaluated through open field test(OFT)and elevated plus maze(EPM),while depressive-like behaviors were examined with sucrose preference test(SPT)and tail suspension test(TST).HE staining was used to observe the histopathological changes in mouse tissues.Radioimmunoassay(RIA)was employed to detect the expression of pro-inflammatory cytokines,TNF-α and IL-1 β,as well as anti-inflammatory cytokines,IL-4 and IL-10 in the serum,brain,jejunum,and spleen samples.Additionally,metagenomic sequencing was performed to assess alterations in the gut microbiota composition.Results Long-term RF radiation led to a maximal increase of 0.59℃in the core body temperature,but had no significant effects on cognitive function,anxiety-like behaviors,or depressive-like behaviors,or apparent damage of the hippocampal or jejunal tissues in the exposed mice.However,RF exposure significantly up-regulated the expression of the pro-inflammatory cytokine TNF-α in serum(P<0.05),and did not significantly alter the concentrations of other cytokines(IL-1β,IL-4,IL-10),caused significant decrease in α-diversity of the intestinal microbiota(P<0.01),with reduced relative abundances of Ligilactobacillus murinus and Acetatifactor muris(P<0.05),while elevated abundances of Lachnospiraceae bacterium(P<0.01).Conclusion Long-term exposure to 2.65 GHz RF radiation induces systemic inflammatory responses and disrupts gut microbiota homeostasis in mice.

AIM:To investigate the protective effects of Klotho protein against hypoxia/reoxygenation(H/R)-in-duced damage in rat cardiomyocytes,and to elucidate its underlying mechanisms.METHODS:Rat cardiomyocyte H9c2 cells were divided into 4 groups:control,H/R,low-concentration(1 μmol/L)Klotho+H/R,and high-concentration(10 μmol/L)Klotho+H/R groups.Cells were pretreated with Klotho at specified concentrations before induction of H/R injury.Flow cytometry was used to determine cardiomyocyte apoptosis rates,while reactive oxygen species(ROS)levels were measured using the DCFH-DA probe.Additionally,superoxide dismutase(SOD)activity and malondialdehyde(MDA)content were assessed using biochemical assay kits.Mitochondrial membrane potential was evaluated using the JC-1 as-say,and activity of caspase-3 and caspase-9 was quantified.Western blot analysis was conducted to measure the protein expression of cytochrome C(Cyt-C),B-cell lymphoma-2(Bcl-2),and Bcl-2-associated X protein(Bax)in cardio-myocytes from each group.RESULTS:Compared with the control group,the H/R group exhibited significantly increased apoptosis rates(P<0.05),elevated ROS levels and MDA content,decreased SOD activity(P<0.05),reduced mitochon-drial membrane potential(P<0.05),increased caspase-3 and caspase-9 activity(P<0.05),decreased mitochondrial Cyt-C and Bcl-2 protein expression(P<0.05),and increased cytoplasmic Cyt-C and Bax protein expression(P<0.05).In comparison with the H/R group,both low-and high-concentration Klotho treatments significantly reduced cardiomyocyte apoptosis(P<0.05),lowered ROS levels and MDA content(P<0.05),increased SOD activity(P<0.05),restored mito-chondrial membrane potential(P<0.05),decreased caspase-3 and caspase-9 activity(P<0.05),increased mitochondrial Cyt-C and Bcl-2 expression(P<0.05),and decreased cytoplasmic Cyt-C and Bax expression(P<0.05).Notably,the high-concentration Klotho group demonstrated more pronounced protective effects(P<0.05).CONCLUSION:Klotho protein exerts protective effects against H/R-induced cardiomyocyte injury,possibly by inhibiting mitochondria-mediated apoptosis.

AIM:To investigate the protective effects of Klotho protein against hypoxia/reoxygenation(H/R)-in-duced damage in rat cardiomyocytes,and to elucidate its underlying mechanisms.METHODS:Rat cardiomyocyte H9c2 cells were divided into 4 groups:control,H/R,low-concentration(1 μmol/L)Klotho+H/R,and high-concentration(10 μmol/L)Klotho+H/R groups.Cells were pretreated with Klotho at specified concentrations before induction of H/R injury.Flow cytometry was used to determine cardiomyocyte apoptosis rates,while reactive oxygen species(ROS)levels were measured using the DCFH-DA probe.Additionally,superoxide dismutase(SOD)activity and malondialdehyde(MDA)content were assessed using biochemical assay kits.Mitochondrial membrane potential was evaluated using the JC-1 as-say,and activity of caspase-3 and caspase-9 was quantified.Western blot analysis was conducted to measure the protein expression of cytochrome C(Cyt-C),B-cell lymphoma-2(Bcl-2),and Bcl-2-associated X protein(Bax)in cardio-myocytes from each group.RESULTS:Compared with the control group,the H/R group exhibited significantly increased apoptosis rates(P<0.05),elevated ROS levels and MDA content,decreased SOD activity(P<0.05),reduced mitochon-drial membrane potential(P<0.05),increased caspase-3 and caspase-9 activity(P<0.05),decreased mitochondrial Cyt-C and Bcl-2 protein expression(P<0.05),and increased cytoplasmic Cyt-C and Bax protein expression(P<0.05).In comparison with the H/R group,both low-and high-concentration Klotho treatments significantly reduced cardiomyocyte apoptosis(P<0.05),lowered ROS levels and MDA content(P<0.05),increased SOD activity(P<0.05),restored mito-chondrial membrane potential(P<0.05),decreased caspase-3 and caspase-9 activity(P<0.05),increased mitochondrial Cyt-C and Bcl-2 expression(P<0.05),and decreased cytoplasmic Cyt-C and Bax expression(P<0.05).Notably,the high-concentration Klotho group demonstrated more pronounced protective effects(P<0.05).CONCLUSION:Klotho protein exerts protective effects against H/R-induced cardiomyocyte injury,possibly by inhibiting mitochondria-mediated apoptosis.

Objective To investigate the effects of 0.5 Gy 60Co γ-ray irradiation on intestinal tissue injury and intestinal microflora in mice.Methods C57BL/6N mice were irradiated with 0.5 Gy 60Co γ-ray at 1 d,3 d,7 d and 14 d after irradiation.Jejunum tissues were fixed and frozen,and feces were frozen.Hematoxylin-eosin staining was used to observe the pathological injury to jejunum after irradiation,ki67 immunohistochemical staining was adopted to detect the proliferation of jejunum crypt cells,and TdT-mediated dUTP nick end labeling was employed to detect the apoptosis of jejunum crypt cells.The expressions of TNF-α,IL-1β,IL-6 and IL-10 cytokines in small intestines were detected via radioimmunoassay.The changes of intestinal flora in mice after irradiation were analyzed by metagenomic sequencing,and LEfSe analysis and ROC analysis were used to screen the bacteria with significant differences.Results After 0.5 Gy 60Co γ-ray irradiation,the proliferative cells of the jejunal crypt were significantly decreased at 1 d after irradiation(P＜0.05),while the apoptotic cells were significantly increased at 1 and 3 d after irradiation(P＜0.01).The expression of TNF-α at 7 and 14 d after irradiation,that of IL-1 β at 1,3,7 and 14 d after irradiation and that of IL-6 at 3,7 and 14 d after irradiation were significantly increased(P＜0.05),while the expression of IL-10 at 7 and 14 d after irradiation was significantly decreased(P＜0.05).After 0.5 Gy 60Co γ-ray irradiation,intestinal flora composition changed significantly at phylum,genus and species levels,and Lactobacillus murinus,Lactobacillus johnsonii,Alistipes-unclassified,Mucispirillum schaedleri underwent the most significant changes and had higher LDA scores.Conclusion The whole body irradiation of 0.5 Gy 60Co γ-ray can cause intestinal tissue damage and change the composition of intestinal flora in mice.

Objective:To investigate the effects of 2 650 MHz radiofrequency (RF) exposure on the behavior and neurotransmitter release of mice.Methods:Adult male C57BL/6N mice were divided into a normal control (CON) group and a radiofrequency radiation (RFR) group using the random number table method. The mice in the RFR group were subjected to single-dose whole-body exposure to a uniform 2 650 MHz RF electromagnetic field for 3 h. During the RF exposure, the field strength in the effective working area of the RF radiation platform was measured using an electromagnetic radiation analyzer, and the changes in the anal temperature of the mice were monitored using an optical fiber thermometer. Moreover, the changes in the cognition, social interaction, and emotion of the mice were determined through the new object recognition test, social preference test, and open field test. Finally, the changes in the hippocampal neurotransmitter release levels of the mice were detected using microdialysis sampling and mass spectrometry, and the changes in the hippocampal tissue structure and ultrastructure were observed via microscopy.Results:Under the test conditions, RF radiation improved the anal temperature of the mice, with a maximum increasing amplitude of 0.61℃, falling within the range of thermal safety. The mice in the RFR group experienced a significant decrease in the frequency and time for exploring new objects ( t=4.50, 2.53, P < 0.05) in the new object recognition test, a significant decrease in the frequency ( t=0.08, P<0.01) and time ( t=0.03, P<0.05) for exploring other mice in the social preference test, and no significant change in the frequency and time for exploring the central area ( P > 0.05) in the open field test. Compared to the CON group, the RFR group showed an increase in the release of 5-hydroxytryptamine (5-HT) ( t=-2.56, P < 0.05) and a decrease in the release of acetylcholine (ACh) ( t=2.21, P < 0.05), no significant difference in the release of glutamate (Glu) and γ-aminobutyric acid (GABA) ( P > 0.05), and no evident damage to the hippocampal tissue and structure and synaptic ultrastructure. Conclusions:2 650 MHz RF radiation may induce cognitive impairment and abnormal social preference in mice, which is attributed to neuronal dysfunctions and neurotransmitter release disorders under RF exposure.

Objective:To clarify the effects of microwave radiation on anxiety-like behavior, the histomorphology of the secondary visual cortex, and calcium activity in neurons.Methods:36 C57BL/6N mice were selected and divided into control group and microwave radiation group according to the random number table method. In the simple behavioral testing, there were 8 mice in the control group and 7 mice in the radiation group. Combining fiber optic recording with behavioral experiments, there were 8 mice in the control group and 7 mice in the radiation group. Hematoxylin-eosin (HE) staining was conducted with 3 mice in each group. A high-power microwave simulated source in the X-band with a center frequency of 9.875 GHz and an average power density of 12 mW/cm 2 was used to irradiate the mice for 15 minutes, establishing a microwave radiation animal model. Then, anxiety-like behavior changes in the radiation group were identified using the open-field and elevated plus maze (EPM) tests. The effects of microwave radiation on the histomorphology of the secondary visual cortex were investigated using HE staining and optical microscopy. Based on the genetically encoded calcium imaging technique, as well as optical fiber recording combined with behavioral paradigms in the open field and the EPM, the changes of calcium activity in neurons in the V2M region of the secondary visual cortex were detected. Results:Compared to the control group, the radiation group showed a significant decrease in the frequency of exploring the central region of the open field and the open arm of the EPM ( t = 2.24, 3.10, P < 0.05). Furthermore, the radiation group exhibited the degeneration and apoptosis of some neurons in the secondary visual cortex, primarily manifested as pyknosis and deep staining, cell body shrinkage, and the slightly widening of perivascular space. Fiber optic recordings and behavioral experiments indicated that compared to the control group, mice in the radiation group exhibited significantly increased calcium activities in neurons of the secondary visual cortex when exploring the central region of the open field ( t = -2.75, P < 0.05) or the open arm of the EPM ( t = -2.77, -3.41, P < 0.05) compared to those before radiation after microwave exposure. Conclusions:Microwave radiation can induce anxiety-like behaviors and histopathological changes in the secondary visual cortex. Increased calcium activity in neurons of the secondary visual cortex is proved to be an important mechanism underlying the changes in anxiety-like behavior due to microwave radiation.

Objective:To study the therapeutic effect Tetrandrine (TET) on striatal injury caused by microwave radiation and underlying mechanism.Methods:C57BL/6N mice were randomly divided into blank control group (C), radiation control group (R), TET group (TET) and TET combined with radiation group (TET+ R). The mice of radiation group were exposed to 2.856 GHz 8 mW/cm2 microwave on whole-body for 15 min. TET (60 mg/kg) was injected intraperitoneally once a day for 3 consecutive days. The TET structure was verified by ultraviolet spectrophotometry. The open field experiment was used to detect the change of anxiety in mice. Histopathological and ultrastructural changes of the striatum were observed by light microscopy and transmission electron microscopy (TMT). Quantitative real-time PCR (qPCR) was used to detect gene expression changes of voltage-gated calcium channel (VGCC) subtype in the striatum.Results:The open field experiments showed that the time and distance of mice to explore the central region after microwave radiation were significantly lower than that before radiation ( t=4.60, 5.18, P<0.01), and the TET administration significantly improved these changes ( F=1.43, 4.37, P < 0.05). 7 d after microwave radiation, some neuronal nuclei in the striatum of mice contracted and could be stained deeply, which was more obvious in the globus pallidus area. The partial neuronal apoptosis, swelling and cavitation of glial cell mitochondria, blurring of synaptic gaps, and widening of perivascular gaps in the striatum were observed by TMT. The above lesions were significantly rescued after TET administration. But both microwave radiation and TET administration had no significant effect on the gene expressions of striatal VGCC ( P > 0.05). Conclusions:TET has a therapeutic effect on anxiety-like behavior and structural damage of striatum caused by microwave radiation, which is independent of the expression of striatal VGCC genes.

Objective To evaluate the long-term prognostic value of coronary CT angiography-derived fractional flow reserve(CT-FFR)in elderly patients with coronary heart disease(CHD).Methods A retrospective analysis was performed on 1133 patients with clinically suspected CHD from a prospective observational study based on coronary CTA and CT-FFR at the General Hos-pital of Eastern Theater from April 2018 to March 2019,and 330 elderly CHD patients were even-tually included.According to major adverse cardiovascular events(MACE)occurred or not,295 patients were assigned into non-MACE group and 35 patients into the MACE group.Based on cor-onary CTA data,plaque features were analyzed and CT-FFR values were measured in all lesioned vessels.The relationship of plaque features and CT-FFR with MACE was evaluated by using Cox proportional risk regression model,Kaplan-Meier survival curve,and ROC curve analyses.Results The patients with coronary stenosis(≥50％)or CT-FFR value ≤0.8 had a higher risk of MACE(P＜0.01).Univariate Cox analysis showed that coronary stenosis ≥50％and CT-FFR value 0.8 were risk factors of MACE(P＜0.01).After adjusting confounding factors,multivariate Cox analysis indicated that CT-FFR ≤0.8(HR=17.037,95％CI:5.060-57.358,P=0.000)was only independent predictor for MACE.The risk prediction model based on CT-FFR presented better performance than the model based on coronary CTA stenosis(C-index:0.820 vs 0.696,P=0.000).Conclusion CT-FFR≤0.8 is an important independent predictor for long-term MACE in elderly CHD patients.Clinical risk stratification based on CT-FFR may optimize prognostic man-agement strategies in these patients.