Objective:To investigate the effects of microwave radiation on associative learning and memory function and hippocampal structure of mice.Methods:C57BL/6N mice were ramdomly divided into sham-radiated group ( n=27) and radiation group ( n=2). The radiation group was exposed to microwave at 2.856 GHz, 8 mW/cm 2 for 15 min, then their spatial and associative learning and memory function were examined with the morris water maze and shuttle box behavior experiment. The pathological changes of hippocampal tissue were observed by HE staining and light microscope, the ultrastructural changes of hippocampal tissue were observed by transmission electron microscope. Results:After microwave radiation, the times of mice crossing the platform for the reverse space exploration decreased from(3.60±0.79) times to (2.55±0.47) times( t=2.21, P=0.046), the average active escape rate decreased significantly ( t = 2.70, P<0.05), and the average active latency and the total shock time was significantly prolonged ( t = -3.09, -3.02, P < 0.05). At 8 d after microwave radiation, the nuclei of some neurons in the CA3 and DG regions of the hippocampus were pyknosis. The neurons were apoptotic, the synaptic spaces blurred, the glial cells swollen, and the perivascular spaces widened in the CA3 region of the hippocampus. Conclusions:Microwave radiation can decline the spatial reference memory ability and associative learning and memory ability of mice. The morphological and pathological changes of hippocampus are the structural basis of this dysfunction.

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.

AIM:To investigate the therapeutic effect of menstrual blood-derived endometrial stem cells(MenSCs)on chemotherapy-induced intestinal mucositis and flora disorders in mice,and to explore the potential mecha-nism.METHODS:The mice were randomly divided into 3 groups including normal treatment,cisplatin(Cis)treatment and Cis+MenSC treatment,with 10 mice in each group.To induce intestinal mucositis,the mice were treated with Cis(2 mg·kg-1·d-1)by intraperitoneal injection for 5 consecutive days.Control mice for normal group were received equal vol-umes of normal saline.For Cis+MenSC treatment,MenSCs(1×106)was transplanted into the mice of Cis treated mice through tail vein.The performances and weight changes of mice were examined during the experiment.After the treat-ment,the small intestine and colon were isolated for subsequent HE staining,the ratio of F4/80 and IL-6 positive cells in small intestine were detected by immunohistochemical staining,and the expression of tight junction,inflammation and apoptosis related proteins was detected by Western blot.16S rDNA amplicon sequencing was performed to detect the diver-sity and richness of intestinal flora in mice.RESULTS:Compared to the Cis group,the MenSCs-treated mice showed sig-nificantly increased body weight,relieved intestinal lymphocytes infiltration,alleviated intestinal villous edema,and or-derly arranged glands in intestinal tissues.Further analysis indicated that MenSCs transplantation significantly up-regulat-ed the expression of intestinal tight junction related proteins ZO-1 and occludin in Cis-treated mice(P＜0.05).Subse-quently,MenSCs transplantation significantly inhibited the macrophages infiltration in intestinal tissues(P＜0.01),down-regulated the expression of pro-inflammatory factors IL-1 and IL-6 and pro-apoptotic protein Bax(P＜0.01),while up-regu-lated anti-inflammatory factor IL-10 and anti-apoptotic protein Bcl-2(P＜0.01).Additionally,further microflora sequenc-ing indicated that MenSCs transplantation prevented mice from Cis-induced intestinal flora disorder,and significantly re-duced the abundance of harmful bacteria such as isenbergiella tayi and Anaerotruncus colihominis(P＜0.01).At the same time,the abundance of beneficial bacteria Lactobacillus apodemi was increased(P＜0.05),thereby restoring the composi-tion and function of healthy intestinal flora.CONCLUSION:MenSCs transplantation alleviates the chemotherapy-in-duced damage of intestinal structure,relieves the symptoms of chemotherapy-induced mucositis and restores the homeosta-sis of intestinal flora in mice.