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Objective:To investigate the effects of 40 Hz and 70 Hz frequency flash stimulation on the ability of learning memory and autonomous exploratory in young rats.Methods:Twenty-seven SPF grade male SD rats aged 19-21 days were divided into control group (Ctr group), 40 Hz group and 70 Hz group with 9 in each group according to the random number table.The rats in Ctr group were not given flash stimulation, while rats in the 40 Hz and 70 Hz group were received 40 Hz, 70 Hz flash stimulation (1.5 h/d for 39 days), respectively.The Morris water maze experiment was used to assess the learning and memory ability of rats, and the open field experiment was used to evaluate the ability of autonomous exploratory of rats.Nissl staining was used to assess the morphology of Nissl bodies in the hippocampus CA1 region of the rats.The local field potentials (LFPs) collected from the primary visual cortex (V1 area) region by electrophysiological experiments was used to verify the synchronization of flash evoked neural oscillations.SPSS 23.0 software was used for statistical analysis.The repeated measures ANOVA and one-way ANOVA were used to analyze normal distribution measurement data, and LSD and Tamhane tests were used for further pairwise comparison.The Kruskal-Wallis test was used for non-normal distribution measurement data.Results:(1) The flash stimulation of 40 Hz and 70 Hz both can effectively caused synchronization of neural oscillations in the primary visual cortex of healthy young rats.(2) The results of repeated measures ANOVA analysis showed that there was no interaction effect of grouping and time in the escape latency of young rats in the Morris water maze positioning navigation phase( F=1.326, P>0.05 ). The escape latency had time main effect ( F=40.025, P<0.05), but no grouping main effect ( F=2.039, P>0.05). With the increase of learning days, the escape latency of young rats in each group decreased significantly.There was no interaction effect of grouping and time in the total distance of young rats ( F=2.029, P>0.079). It had time main effect ( F=32.052, P<0.05), but not grouping main effect ( F=2.390, P>0.05) on total distance.With the increase of learning days, the total distance of young rats in each group significantly shortened.On the 6th day of the Morris water maze experiment, there was no statistically significant difference among groups in terms of time in the target quadrant and the number of crossing platforms ( F=2.511, 0.802, both P>0.05). The results of the open field experiment showed that the total distance traveled in the center of young rats in each group was statistically significant ( H=8.935, P<0.05), the total distance traveled in the center in the 70 Hz group (3.80 (2.25, 6.93) m)was significantly longer than that in the 40 Hz group (0.80 (0.72, 1.46) m), P<0.05). The percentage of time spent in the center was statistically significant in the three groups ( H=11.050, P<0.05). Young rats in the 70 Hz group spent significantly higher percentage of time in the center(3.20(2.43, 8.30)) than those in the 40 Hz group (0.95 (0.37, 1.06 ), P<0.05 ). (3) Nissl staining results showed that Nissl bodies in the hippocampal CA1 area of young rats in Ctr, 40 Hz and 70 Hz group were all arranged neatly and tightly, no edema was found in the surrounding stroma, and no obvious inflammatory cell infiltration was found. Conclusion:70 Hz frequency flash stimulation may promote the ability of learning memory and autonomous exploratory of young rats.
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BACKGROUND@#Chronic noise exposure is one environmental hazard that is associated with genetic susceptibility factors that increase Alzheimer's disease (AD) pathogenesis. However, the comprehensive understanding of the link between chronic noise stress and AD is limited. Herein, we investigated the effects of chronic noise exposure on AD-like changes in senescence-accelerated mouse prone 8 (SAMP8).@*METHODS@#A total of 30 male SAMP8 mice were randomly divided into the noise-exposed group, the control group, and aging group (positive controls), and mice in the exposure group were exposed to 98 dB SPL white noise for 30 consecutive days. Transcriptome analysis and AD-like neuropathology of hippocampus were examined by RNA sequencing and immunoblotting. Enzyme-linked immunosorbent assay and real-time PCR were used to further determine the differential gene expression and explore the underlying mechanisms of chronic noise exposure in relation to AD at the genome level.@*RESULTS@#Chronic noise exposure led to amyloid beta accumulation and increased the hyperphosphorylation of tau at the Ser202 and Ser404 sites in young SAMP8 mice; similar observations were noted in aging SAMP8 mice. We identified 21 protein-coding transcripts that were differentially expressed: 6 were downregulated and 15 were upregulated after chronic noise exposure; 8 genes were related to AD. qPCR results indicated that the expression of Arc, Egr1, Egr2, Fos, Nauk1, and Per2 were significantly high in the noise exposure group. These outcomes mirrored the results of the RNA sequencing data.@*CONCLUSIONS@#These findings further revealed that chronic noise exposure exacerbated aging-like impairment in the hippocampus of the SAMP8 mice and that the protein-coding transcripts discovered in the study may be key candidate regulators involved in environment-gene interactions.
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Objective@#To study the effects of different holding gun methods and gun weight on health when standing guard, and propose a way to support the health of long-term standing guard soldiers.@*Methods@#We created different percentile mannequins by Classic JACK, and adjusted the standing guard posture based on its standards for soldiers. The pressure on lumbar L4/L5 and moment on ankles and knees were analysied for different holding gun methods and gun weight. Then the mathematical models of joint load, gun weight and body mass index were studied by multiple regression analysis.@*Results@#Holding gun methods and gun weight influence the force characteristics on ankles, knees and lumbar L4/L5. Holding gun with a brace and hands applying downward force -2 kgf could significantly reduce lumbar L4/L5 pressure. When the hand force is -5, -3, -4, -3, -2, -1, 0, 1, 2 kgf, and the weight of the gun is 0, Lumbar vertebrae L4/L5 joint pressure of people with different body mass index(P1, P5, P55, P95, P99) are the smallest, respectively 269, 281, 321, 408, 444 N, and the same change trend occurs when the weight of the gun is 2, 4, and 8 kg.The moment on ankles and knees were less with the same holding gun method and the hands downward force ranged from 0 to -4 kgf, and the higher the body mass index is, the more the hands downward force needed to make the moment on ankles and knees zero. That is, the moment on ankles could be zero when the hands downward force ranged from -1 to -3 kgf, the moment on knees could be zero when the hands downward force ranged from -1.1 to -3.7 kgf.@*Conclusion@#To reduce the pressure on lumbar L4/L5 and moment on ankles and knees, so as to cut down occupational risk of long-standing operation, we advise the long-term standing guard soldiers holding gun with a brace and hands applying downward force -2 kgf.
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Objective@#To investigate the roles of pattern recognition receptors (PRRs) including Toll-like receptors (TLRs), retinoic acid-inducible geneⅠ-like receptors (RLRs) and nucleotide binding oligomerization domain-like receptors (NLRs) in the pathogenesis of dengue fever (DF) and the induction of immune responses to dengue virus.@*Methods@#Blood samples were collected from patients with DF at three different time points to isolate peripheral blood mononuclear cells (PBMCs) by density gradient centrifugation. Then PBMCs were used to extract ribonucleic acid (RNA). Expression of genes was detected by polymerase chain reaction (PCR) array.@*Results@#Expression of genes relating to PRRs signaling pathways in DF patients increased significantly in the early stage of the disease as compared with those in healthy controls, but decreased gradually during the recovery period. Expression of genes encoding TLR7 and TLR8 was enhanced at the early stage of DF. No significant changes in the expression of TLR3 and TLR9 genes were observed during the course of the disease. The genes encoding RIG-Ⅰ, MDA5 and LGP2 of RLRs family as well as NOD2 and OAS2 of NLRs family were all up-regulated.@*Conclusion@#Signaling pathways mediated by PRRs including TLR7/8, RIG-Ⅰ, MDA5 and so on play an important role in the pathogenesis of DF and the induction of immune responses to dengue virus.
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Objective To investigate the dynamic changes of dengue viral loads and IgM antibody in patients with dengue fever ( DF) and to analyze their relationships with disease severity. Methods A to-tal of 1 508 serum samples were collected from 1 140 hospitalized patients including 1 050 mild cases and 90 severe cases within 10 days after the onset of DF in Guangzhou in 2014. The viral loads were determined by using fluorescence quantitative RT-PCR. ELISA was performed to measure the dengue virus ( DENV)-spe-cific IgM antibody. Results In general, the DENV viral loads in patients declined gradually from 108 copies/ml on day 1 to 103 copies/ml on day 10 after the onset of DF. The viral loads in severe cases were significantly higher than those in mild cases on days 5 to 7 (P<0. 05). The positive rates of DENV RNA in serum samples also decreased with the disease progression from 100% on day 1 to 40% on day 10. Com-pared with the mild cases, the patients with severe DF showed higher positive rates of DENV RNA on day 6 and day 8 (P<0. 05). The DENV-specific IgM antibody could be detected on day 2 and the secretion of IgM antibody increased gradually with the disease progression. The levels of IgM antibody in mild cases were sig-nificantly higher than those in severe cases (P<0. 001). The positive rates of IgM antibody in patients in-creased form 8% on day 2 to 95% on day 6. Higher positive rates of IgM antibody were detected in mild ca-ses on days 5 and 6 as compared with those in patients with severe DF (P<0. 05). Conclusion High viral load and low level of IgM antibody during the fastigium of DF were closely associated with the disease severity.
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OBJECTIVE To investigate the effect of doxazosin(DOX) and metoprolol( MET) on vascular remodeling in rats with abdominal aorta coarctation (AAC). METHODS An animal model was established by AAC. Two weeks later, the rats were treated with DOX (10 mg.kg-1 per day) or MET (20 mg.kg-1 per day) for six weeks. Blood pressure was measured using carotid artery intubation with a MP150 polygraph. The media thickness, wall cross-sectional area and thickness / internal diameter ratio were calculated by morphometry. Vascular fibrosis was evaluated by Masson′s trichrome staining. The collagen and fibronectin expression in vascules was measured by Western blotting. RESULTS Compared with the sham group 〔(17.6±0.5)kPa〕, the mean arterial blood pressure in the model group〔(23.3±0.7)kPa〕 was significantly increased(P<0.05), but was lowered by DOX 〔(20.5±0.7)kPa〕 and MET 〔(19.0±0.4) kPa〕 (P<0.05). Moreover, HE staining showed that tunica media thickness, artery vessel area and thickness / inner diameter in the model group were increased by 39.5%, 46.4% and 27.0%(P<0.05), respectively. The tunica media thickness was decreased by 16.0% and 26.1%( P<0.05), respectively, the artery vessel area by 22.8% and 26.1%(P<0.05), respectively, and the thick-ness / inner diameter by 17.0% and 26.0%( P<0.05) when the rats were treated with DOX and MET. Masson staining showed that the collagen accumulation in vascules increased, suggesting that AAC induced fibrosis. Meanwhile, vascular fibrosis induced by AAC was also reduced by MET or DOX. Western blotting also proved that the increase of collagen and fibronectin induced by AAC could be attenuated by DOX and MET(P<0.05). CONCLUSION DOX and MET are effective in suppressing the role of norepi-nephrine in vassels, which can attenuate AAC-induced vassels remodeling by preventing the binding between norepinephrine and adrenoceptors.
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Objective To study the possibility of the plasma level of heat shock protein 70(HSP70) being used as a bi-ological marker of military stress .Methods Soldiers who returned from a 6-month-navigation were chosen as subjects , the HSP70 level of plasma was measured with the ELISA assay and stress questionnaires and Self -rated Health Measurement Scale (SRHMS) were used to measure the stress level .Results The soldiers′plasma level of HSP70 was 31.40%higher than that of the control .The stress questionnaire indicatesd that the level of thinking and anxiety , negative mood and somat-ic symptoms were higher than normal .The SRHMS indicated that the level of physiological health ,mental health and social health was lower than normal .The plasma level of HSP70 was associated with the level of military stress .Conclusion The plasma level of HSP70 may be used as an important predictor of military stress .It can predict the level of military stress injury.
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Objective To systematially observe the different patterns and leves of military stress on modified multitle-platform method the level of stress-related hormones in rats .Methods A sleep deprivation model was established by water environment modified multiple-platform method(MMPM).A restraint stress model was established by self-made bondage cage.Chronic unpredictable mild stress ( CUMS) model was established by action control , cage damp, cage tilt, night lightening, water and food fasting , empty bottles stimulation and group feeding methods .Cortisol, catecholamines and 5-HT levels were detected to observe the different military stress loads and modes on the level of stress hormones .Results The level of serum cortisol increased significantly ( P <0.05 ) after 5 days of sleep deprivation .The level of serum catecholamines increased significantly (P<0.05) after 1 day of sleep deprivation.The cortisol concentration increased and the level of 5-HT decreased in serum after 4 weeks CUMS.The level of catecholamines increased significantly (P<0.05) after 2-8 weeks of CUMS, increased significantly (P<0.05) after 1 week of restraint stress , and returned to normal after 3-4 weeks of restraint stress .The level of serum cortisol increased significantly after 3 -4 weeks of restraint stress . Conclusion Cortisol levels gradually increased with the level of stress in different military stress modes , which can serve as an index to evaluate the level of different stress modes .