Intermittent hypoxic preconditioning relieves fear and anxiety behavior in post-traumatic stress model mice / 生理学报

Intermittent hypoxia (IH) has preventive and therapeutic effects on hypertension, myocardial infarction, cerebral ischemia and depression, but its effect on post-traumatic stress disorder (PTSD) has not been known. In this study, we used inescapable electric foot shock combined with context recapture to build PTSD mouse model. The levels of fear and anxiety were valued by the open field, the elevated plus maze (EPM) and the fear conditioning tests; the level of spatial memory was valued by Y maze test; the number of Fos positive neurons in hippocampus, amygdala and medial prefrontal cortex was valued by immunohistochemical staining; and the protein expressions of hypoxia inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF) and brain derived neurotrophic factor (BDNF) in these brain area were valued by Western blot. The results showed that IH and model (foot shock) had an interaction on percentage of entering open arms (OE%) in EPM and freezing time and the number of fecal pellets in fear conditioning test. IH increased OE% in EPM and reduced the freezing time and the number of fecal pellets in fear conditioning test in PTSD model mice. At the same time, IH reduced the number of Fos positive neurons in the hippocampus, amygdala and medial prefrontal cortex of PTSD model mice, and increased the protein expression levels of HIF-1α, VEGF and BDNF in these brain tissues. In conclusion, IH pretreatment can relieve fear and anxiety behavior in post-traumatic stress model mice, suggesting that IH may be an effective means of preventing PTSD.

Effects of simulated high-altitude hypobaric hypoxia on cardiac structure and function in rats / 中国应用生理学杂志

OBJECTIVE@#To investigate the effects of simulated hypobaric hypoxia environment at 7 000 m above sea level on cardiac structure and function in rats.@*METHODS@#A total of 96 male SD rats were randomly divided into high-altitude hypobaric hypoxia group (hypoxia group) and normobaric normoxia group (control group). Rats of hypoxia group were placed in a large cabin simulated 7 000 m high-altitude hypobaric hypoxia environment. Operating time 23 h / d, the control circadian ratio of approximately 12 h:12 h. The rats in control group were bred under normobaric normoxia. The hypoxic group was divided into 3 d, 7 d, 14 d, 28 d groups according to hypoxic time, 12 rats in each group. Changes of structure and function of heart due to hypoxia were evaluated by echocardiography and electrocardiogram. Myocardial pathological changes were analyzed by hematoxylin-eosin staining(HE).@*RESULTS@#Compared with the control group at the same time point ①With prolonged exposure to hypobaric hypoxia, the growth ratio of body mass in rats is slower. Arterial oxygen saturation was significantly lower in both 14 d and 28 d (P＜0.05). ② Left ventricular end-diastolic anterior wall thickness (LVAWD) and left ventricular end-diastolic posterior wall thickness (LVPWD) of rats in 28 d were increased significantly (P＜0.05). Left ventricular end-diastolic diameter (LVIDD) and left ventricular internal dimension systole (LVIDS) of rats in 28 d were decreased significantly (P＜0.05, P＜0.01). Left ventricular ejection fraction (EF), fractional shortening of left ventricle (FS), pulmonary vein (PV) peak velocity and PV peak gradient of rats in 7 d were decreased significantly (P＜0.05, P＜0.01). ③The QRS and QT interval period were significantly prolonged in 14 d and 28 d (P＜0.05, P＜0.01). The ST was significantly lower in 3 d and 7 d (P＜0.05, P＜0.01). The amplitude of R wave gradually shifted downward in 7 d, 14 d, 28 d (P＜0.05, P＜0.01). ④The red blood cell (RBC), hemoglobin (HGB), red blood cell distribution width (RDW) in hypoxic group were increased significantly (P＜0.01). The platelet count (PLT) count was decreased significantly in 14 d and 28 d (P＜0.01). The serum creatinine (CR) was increased significantly in 14 d and 28 d (P＜0.05). ⑤Pathological changes such as myocardial edema, sarcolemma condensate, focal degeneration and necrosis with inflammatory cell infiltration could be found at early stage of hypoxia. Myocardial compensatory repair such as myocardial fibroblasts proliferation was significant at end stage of hypoxia.@*CONCLUSION@#Left ventricular systolic functions of rats were decreased significantly after exposure to high altitude hypoxia hypobaric. The left ventricular systolic functions would recovery compensatory after one week exposed to high altitude hypoxia hypobaric.

Cortical Inflammation is Increased in a DSS-Induced Colitis Mouse Model / 神经科学通报·英文版

While inflammatory bowel disease (IBD) might be a risk factor in the development of brain dysfunctions, the underlying mechanisms are largely unknown. Here, mice were treated with 5% dextran sodium sulfate (DSS) in drinking water and sacrificed on day 7. The serum level of IL-6 increased, accompanied by elevation of the IL-6 and TNF-α levels in cortical tissue. However, the endotoxin concentration in plasma and brain of mice with DSS-induced colitis showed a rising trend, but with no significant difference. We also found significant activation of microglial cells and reduction in occludin and claudin-5 expression in the brain tissue after DSS-induced colitis. These results suggested that DSS-induced colitis increases systemic inflammation which then results in cortical inflammation via up-regulation of serum cytokines. Here, we provide new information on the impact of colitis on the outcomes of cortical inflammation.

Change of intracellular Caconcentration and related signaling pathway in hippocampal cells after high-intensity sound exposure / 生理学报

High-intensity sound often leads to the dysfunction and impairment of central nervous system (CNS), but the underlying mechanism is unclear. The present study was aimed to investigate the related mechanisms of CNS lesions in Bama miniature pig model treated with high-intensity sound. The pigs with normal hearing were divided into control and high-intensity sound (900 Hz-142 dB SPL, 15 min) groups. After the treatment, hippocampi were collected immediately. Fluo-4 was used to indicate intracellular Caconcentration ([Ca]) change. Real-time PCR and Western blot were used to detect mRNA and protein expressions of calcium-sensing receptor, L-Cachannel α2/δ1 subunit, PKC and PI3K, respectively. DAPI staining was used to identify nuclear features. The result showed that high-intensity sound exposure resulted in significantly swollen cell nucleus and increased [Ca]in hippocampal cells. Compared with control group, high-intensity sound group showed increased levels of PI3K, PKC and L-Cachannel α2/δ1 subunit mRNA expressions, as well as up-regulated PKC and calcium-sensing receptor protein expressions. These results suggest that the high-intensity sound activates PKC signaling pathway and induces calcium overload, eventually leads to hippocampal injury, which would supply a novel strategy to prevent nervous system from high-intensity sound-induced injury.

Establishment and evaluation of a murine model of brain injury induced by high altitude hypoxic inflammation / 生理学报

The aim of this study was to develop a murine model of brain injury induced by high altitude hypoxic inflammation. In the study, we used a decompression chamber to mimic an acute hypobaric hypoxia, and 8-week-old male C57BL/6 mice were intraperitoneally injected with 5 mg/kg lipopolysaccharide (LPS) to induce inflammatory response. We determined the levels of pro-inflammatory factors (IL-6, TNF-α) and anti-inflammatory factor (IL-10) in mice serum using ELISA assays to confirm the high altitude hypoxic inflammation, and verified the brain injury after the inflammation using hematoxylin-eosin (HE) staining. The results showed that, among four experiment groups (ctrl, acute hypobaric hypoxia, LPS, and acute hypobaric hypoxia plus LPS groups), the acute hypobaric hypoxia plus LPS treatment group displayed the highest levels of IL-6, TNF-α, and IL-10. Meanwhile, the acute hypobaric hypoxia plus LPS treatment group showed the most severe cortex and hippocampus injuries, including cellular swelling, the widened pericellular spaces, angiogenesis, and shrunken neurons with darkly stained pyknotic nuclei, etc. Strikingly, nuclei ventrales posteriors thalami were found to be more sensitive to acute hypobaric hypoxia plus LPS treatment, and their destroy degrees were higher than those neurons in cortex and hippocampus. These results suggested that we established a reliable murine model of brain injury induced by high altitude hypoxic inflammation, and might be useful to the relevant studies.

Rodent models for experimental heat stroke research / 中国应用生理学杂志

Because of the aggressive threaten of heat stroke and a lack of understanding of the mechanism of action, mammal animal models for experimental heat stroke were well developed. During the past 5 decades, anesthetized mouse, rat, rabbit, dog, baboon and monkey were used as animal model for experimental heat stroke. However, anesthetized mammals models have some limitations, such as neuroprotective effect of anesthetic agents, possible disturbance on injury and recovery of stroke animals by anesthetic agents, difficulty of discussing animal behavior before and after heat stroke, it was also difficult for the models to evaluate cognitive function of animal under hot environment. Considering humanitarian, only awaked and unrestrained mouse heat stroke model was accepted so far. Therefore, we also developed an awaked and unrestrained rat heat stroke model, and found it was helpful to evaluate drug effectiveness for animal behavior and cognitive function under hot environment.

Shear bond strengths between alumina-toughened zirconia cores and veneering ceramics and their susceptibility to aging

OBJECTIVE@#To evaluate the shear bond strength (SBS) between alumina-toughened zirconia (ATZ) cores and veneering ceramics, investigate the effect of aging in artificial saliva on SBS and compare it with that of yttria-stabilized tetragonal zirconia polycrystals(Y-TZP).@*METHODS@#Bars of ATZ and Y-TZP were layered with veneering ceramics in accordance to the recommendation of the manufacturer. Half of each group (n = 10) was aged at 134 °C (under 2 bar pressure) in an autoclave for 48 h. Subsequently, all specimens were subjected to shear force in a universal testing machine. The interface and fractured surface of the specimens were evaluated using scanning electron microscopy and X-ray energy dispersive spectroscopy.@*RESULTS@#The initial mean SBS values in MPa±SD were 28.9±8.0 for ATZ and 26.2±7.6 for Y-TZP. After aging, the mean SBS values for ATZ and Y-TZP were 22.9±4.9 MPa and 22.8±6.9 MPa, respectively. Neither the differences between the SBS values of the ATZ and Y-TZP groups nor the influence of aging on all groups were statistically significant.@*CONCLUSIONS@#The SBS between the ATZ core and the veneering ceramics was not affected by aging. The SBS of ATZ to veneering ceramics was not significantly different compared with that of Y-TZP.

Effect of quinacrine on inflammatory reaction of blood system induced by microwave irradiation / 中国实验血液学杂志

This work was aimed to investigate the effect of quinacrine on peripheral granulocytes and lymphocytes, interleukin 1 (IL-1) and interleukin 6 (IL-6) in peripheral blood serum of inflammatory reaction induced by microwave irradiation, and observe the protective effect of quinacrine against microwave irradiation injury. BALB/c mice were suffered from microwave irradiation with the total intensity of 50 mW/cm(2) for 30 minutes, at 1 hour before irradiation quinacrine (12.6 mg/kg or 50.4 mg/kg) was orally administrated. Mice received same volume of water for injection instead of quinacrine were named as microwave irradiation group (MR group), and mice received no microwave irradiation but stayed in microwave irradiation environment also for 30 min were set as control. After microwave irradiation, mice were sacrificed and peripheral blood cells were analyzed with cytoanalyzer, and mice serum interleukin-1β, interleukin-6 were detected by radioimmunoassay. The results showed that microwave irradiation increased the count of peripheral granulocytes and lymphocyte along with prolongation of time, while the increase of these cells in mice administrated quinacrine was markedly delayed. The level of IL-1β in serum of mice was significantly increased after 1 day of microwave irradiation (50 mW/cm(2)), and recovered to normal level after 7 days. The 2 concentrations of quinacrine (12.6 mg/kg, 50.4 mg/kg) could suppress level of IL-1β in serum induced by microwave irradiation. The level of IL-6 in serum of mice was gradually increased after microwave irradiation with intensity of 50 mW/cm(2) for 7 days, but quinacrine administration could delay the rise of IL-6 level, specially within time of 2 days. It is concluded that the quinacrine administration can delay the increase of peripheral granulocytes and lymphocytes inducted by microwave irradiation, and may partially suppress the rise of IL-1β and IL-6 in serum. The results of this study suggest that the quinacrine can provide some protective effect against microwave irradiation injury.

Evaluation of alumina effects on the mechanical property and translucency of nano-zirconia all-ceramics / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To study the effects of alumina content on sintered density, mechanical property and translucency of zirconia nanocomposite all-ceramics.</p><p><b>METHODS</b>Specimens of zirconia nanocomposite all-ceramics were divided into five groups based on their alumina content which are 0% (control group), 2.5%, 5.0%, 7.5% and 10.0% respectively. The sintered densities were measured using Archimedes' method. Specimens' bending strengths were measured with three-point bending test (ISO 6872). The visible light transmittances were measured with spectrophotometric arrangements and the fractured surfaces were observed using scanning electron microscope (SEM).</p><p><b>RESULTS</b>The control group of pure zirconia could be sintered to the theoretical density under pressure-less sintering condition. The bending strength was (1100.27 ± 54.82) MPa, the fracture toughness was (4.96 ± 0.35) MPa×m(1/2) and the transmittance could reach 17.03%. The sintered density and transmittance decreased as alumina content increased from 2.5% to 10%. However, the fracture toughness only increased slightly. In all four alumina groups, the additions of alumina had no significant effect on samples' bending strengths (P > 0.05). When the content of alumina was 10%, fracture toughness of specimens reached (6.13 ± 0.44) MPa×m(1/2) while samples' transmittance declined to 6.21%. SEM results showed that alumina particles had no significant effect on the grain size and distribution of tetragonal zirconia polycrystals.</p><p><b>CONCLUSIONS</b>Additions of alumina to yttria-tetragonal zirconia polycrystals could influence its mechanical property and translucency. Additions of the other phase to zirconia ceramics should meet the clinical demands of strength and esthetics.</p>

Quality control of indispensable reagent RBC for ABO typing / 中国实验血液学杂志

The reagent RBC of known blood group is indispensable reagent for detecting antibody in serological identification of ABO blood group. To elevate the accuracy of detection and solve problems for standardization and quality control of prepared reagent RBC, the detection of specificity and affinity of reagent RBC, shaking test, flow cytometry and atomic force microscopy were performed. On the basis of screening and establishing the reagent for quality control, methods for quality inspection and quality control were established. The results indicated that the prepared reagent RBC evaluated in three batches ensured the quality and performance, and decreased the variance between different batches of the products to the utmost. In conclusion, the quality control problems of prepared reagent RBC had been solved and the accuracy of detection for blood types also elevated.

Prophylactic effect of quinacrine against experimental heatstroke / 药学学报

The present study is to assess the prophylactic effect of quinacrine (QA) , an anti-malarial drug, against heatstroke in rats. Conscious rats were orally given equal volume normal saline or QA (dissolved in normal saline and final dosage for rats was 4.5, 9.0 and 18 mg x kg(-1)). An hour later rats were put into a warm water circulated hot chamber (41.0 +/- 0.5) degrees C. Rectal temperature (core temperature, T(co)) of rats in hot chamber was continuously monitored by a thermocouple. T(co) and survival time of rats showed that QA pre-treatment postponed the hyperthermia, and increased the survival time of rats in hot chamber. Primary striatum neurons' culture from new born rats was maintained with D-MEM and 10% FBS. After immuno-cytochemistry identification with antibodies against neural specific proteins, culture received 20 micromol x L(-1) QA only for 1 h and followed by 43.0 degrees C heat treatment for another hour, or 20 micromol x L(-1) QA for 1 h followed by 43.0 degrees C heat treatment for another hour. Control culture received heat treatment only. Cultures were labeled with the fluorescent indicator DPH and the relative membrane fluidity of neurons was measured with the help of fluorescent polarized spectrophotometer. [3H] Arachidonic acid (AA) labeled membrane of E. Coli cells was used as substrate to determine cPLA2 activity of neurons. Gas chromatography and mass spectrum were also employed to detect on the level of fatty acids level in rat striatum neurons. Results from cells indicated that inhibition of cPLA2, reduction the release of active fatty acids such as AA, and possibly, stabilization of the cell membrane which was disturbed by hot treatment, may contribute to the mechanism underlying heat protection and heatstroke preventive effects of quinacrine.

Protective effect of Quinacrine on striatum neurons from heat treatment injury / 中国应用生理学杂志

<p><b>AIM</b>To study the protective effect of Quinacrine(QA) on rat striatum neurons from the injury caused by heat environment treatment, to probe the relationship between cell membrane injury and cellular injury protection, and to seek the possibility of QA as a preventive agent to heat injury.</p><p><b>METHODS</b>Primary cultured striatum neurons from newborn rats were pretreated with QA at different concentration for 1 h, and then heat-treated at 43 degrees C for another 1 h. Cell necrosis was detected by Trypan blue staining, and apoptosis was evaluated through Activated Caspase-3 dye and TdT dye.</p><p><b>RESULTS</b>Heat treatment effected the survival of striatum neurons and resulted in great number of cell death, which was mainly mediated by cell necrosis process. It was shown that treatment of QA itself had little effect on the survival of striatum neurons, while QA pretreatment decreased cellular necrosis caused by following heat treatment.</p><p><b>CONCLUSION</b>QA protects striatum neurons from heat environment injury at about 20 pmol/L, and the protection may mediated by reduction of necrosis.</p>

Effects of bupivacaine and hyaluronidase on the proliferation of muscle satellite cells in adult rats in vivo / 中国应用生理学杂志

<p><b>UNLABELLED</b>To study the effects of Bupivacaine and hyaluronidase on the proliferation of adult rat muscle satellite cells in vivo.</p><p><b>METHODS</b>Immunohistochemistry, hematoxylin and eosin staining, electron micrograph were used.</p><p><b>RESULTS</b>(1) There are few rare desmin positive satellite cells lie in the myofibers of control group and Sterile saline group which are still continual. MMD of control and Sterile saline group is 0.66% +/- 0.57% and 2.48% +/- 1.13% respectively. Sterile saline group has no significant difference than that of the control (P > 0.05). (2) The myofibers of hyaluronidase group are basically continual. The number of desmin positive satellite cells are increased. MMD of Hyaluronidase is 2.52% +/- 1.41% which has no remarkable difference than that of the Sterile saline (P > 0.05). (3) Plentiful necrosis and degeneration myofibers can been seen in Bupivacaine group and Hyaluronidase + Bupivacaine group coinciding with the activation and proliferation of muscle satellite cells. The number of Desmin positive satellite cells are increased significantly and some of which have formed myotubes. MMD of Bupivacaine and Hyaluronidase + Bupivacaine is 19.01% +/- 4.74% and 22.41% +/- 7.64% respectively which have significant change than that of Sterile saline (P < 0.01).</p><p><b>CONCLUSION</b>The local anaesthetic Bupivacaine can induce the significant proliferation of myoblasts and the formation of myotubes in vivo. Hyaluronidase has no significant effect on the proliferation of satellite cells in vivo under this experimental condition.</p>