Effects of repeated immobilization stress on hypothalamic-pituitary- ovarian axis in female rats / 中国应用生理学杂志

To explore the effects of repeated immobilization stress on hypothalamic-pituitary-ovarian axis in female rats. Methods: Forty female SD rats were randomly divided into two groups: control group (n=20) and experimental group (n=20). One group was fed normally, the other group was subjected to incremental load restraint stress. Brake stress once a day in the retainer (starting at 9: 00 a.m.), braking for 2 hours on the first day, increasing load by 0.5 hours a day for two weeks. Body weight, estrous cycle, sex hormone, organ coefficient, pathology and expression of related genes were detected to explore the harm of hypothalamic-pituitary-ovarian axis. Repeated immobilization stress caused weight loss, prolonged estrous cycle, and changed the organ coefficient and morphology of ovaries and uterus. QPCR technique was used to detect the related genes. It was found that the expressions of gonadotropin releasing hormone, pituitary gonadotropin releasing hormone receptor, follicle stimulating hormone and luteinizing hormone mRNA were decreased significantly, while the expressions of ovarian follicle stimulating hormone and luteinizing hormone receptor mRNA were increased significantly. The expression of estrogen receptor mRNA in ovary and uterus was decreased significantly. Repeated immobilization stress may disrupt the estrous cycle by interfering with the endocrine regulation of the hypothalamic-pituitary-ovarian axis, thus damaging the gonadal and reproductive endocrine function of female animals.

Effects of acute cold exposure on pulmonary proinflammatory cytokine of rat / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To study the effects of acute cold exposure on the inflammation and pathologic injuries in pulmonary of rats, and explore the mechanism induced by cold stress.</p><p><b>METHODS</b>Forty male Wistar rats were randomly divided into five groups(n = 8): control group (23 ± 2) °C 2.5 h, -25°C 0.5 h group, -25°C 1 h group, -25°C 2 h group and -25°C 2.5 h group. Rats were exposed to cold at -25°C and no wind by keeping them in a low temperature chamber except control group. Rectal temperatures of the rats were measured before and after cold exposure. The morphological changes of pulmonary were observed by the optics microscope. The levels of tumer necrosis factor-α(TNF- α), interleukin-6 (IL-6) and interleukin-β (IL-1β) in lung tissue homogenate were measured by ELISA.</p><p><b>RESULTS</b>Compared to the control group, body core temperatures of the -25°C 1 h group, -25°C2 h group and -25°C 2.5 h group were decreased significantly, and the D-values of rectal temperature were increased before and after cold exposure (P < 0.05). The infiltration of inflammatory cells and alveolar edema fluid appeared in the lung tissue of the -25°C 2.5 h group. The concentrations of tumor necrosis factor-α (TNF α), interleukin-6 (IL-6) and inter- leukin-1β (IL-1β) in lung tissue homogenate were increased significantly in -25°C l h group, -25°C 2 h group and -25C° 2.5 h group (P < 0. 05).</p><p><b>CONCLUSION</b>The infiltration of inflammatory cells and the increase in proinflammatory cytokine from pulmonary may lead to the lung tissue injury after acute cold exposure.</p>

Regulative effects of vessel active drugs on extremital skin temperature of experimental animals exposed to cold / 中国应用生理学杂志

<p><b>OBJECTIVE</b>Using an experimental model of animals exposed to cold to evaluate the regulative effects of prazosin hydrochloride (Pra) and racanisodamine (Ani) on extremital skin temperature of rats and mice.</p><p><b>METHODS</b>Eighty animals were randomly divided into eight groups according to the drug dosage. After been administered with drugs by intragastric at room temperature for 60 min, the animals were moved into specified temperature (5 degrees C,18 degrees C) environment and the skin temperatures at the 1/3 site at the proximal end of tail were measured by infrared camera on 180 min and 300 min. Effects of drug were evaluated by changes in tail skin temperatures.</p><p><b>RESULTS</b>Pra and Ani combination raised the extremital skin temperature of experimental animals significantly in a dose-dependent manner, while single use of Pra was not potent to rats and less potent to mice, and single use of Ani could not raise extremital skin temperature of both rats and mice. Change of rectal temperature in mice showed that Pra and Ani combination did not affect core temperature.</p><p><b>CONCLUSION</b>Pra and Ani combination could significantly raise extremital skin temperature of rats and mice exposed to cold, and would not affect their core (rectal) temperature.</p>

The damage effects of hypothermia combined with hypoxia on rat pulmonary microvascular endothelial cells / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To study the synergistic effects of hypothermia and hypoxia on the damage of pulmonary microvascular endothelial cells (PMVEC) in rat.</p><p><b>METHODS</b>Primary PMVECs were obtained by complex phosphoesterasum digesting from isolated lung tissues of Wistar rats, the PMVECs were identified by phase contrast microscope and immunofluorescence studies for CD31 antigen and bandeiraea simplicifolia isolectin (BSI) binding test. Factorial design was adopted in trial according to hypothermia and hypoxia existing or not. Using corresponding kit measured the levels of lactate dehydrogenase (LDH) activity in cell medium. Level of nitric oxide (NO) concentration was measured by Griess Assay. RT-PCR was used to examine the expression of vascular endothelial growth factor (VEGF), endothelin-1 (ET-1) mRNA in PMVECs.</p><p><b>RESULTS</b>The monolayer of cultured PMVECs displayed the shape of pavingstone. CD31 antigen and binding BSI results by fluorescence microscope identified the cultured cells were PMVECs. Compared to the control group, LDH activity and VEGF, ET-1 expression levels were significantly increased in hypothermia group, hypoxia group and hypoxia combined with hypothermia group. And the levels of NO concentration were reduced in these three groups. The results of One-way ANOVA showed that there was a synergistic effect between hypothermia and hypoxia.</p><p><b>CONCLUSION</b>Hypothermia and hypoxia both have an effect on PMVECs whether in altering the cell permeability or in releasing of vasoactive substances including NO and ET-1. In addition, there is a synergistic effect between hypothermia and hypoxia.</p>

Effects of low temperature exposure on dermal microvascular endothelial cells function / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To explore the damage effects and expression of vascular endothelial growth factor (VEGF) exposed with different low-temperatures on rat dermal microvascular endothelial cells (DMVECs).</p><p><b>METHODS</b>Primary DMVECs were obtained by discontinuous Percoll gradient centrifugation. The DMVECs were identified by phase contrast microscope and immunofluorescence studies for CD31 antigen. Applied 28 degrees C, 12 degrees C and 0 degrees C to interfere with rat DMVECs as cold-exposure model. The changes of cells morphology were observed under invert microscope. The membrane integrity was determined by lactate dehydrogenase (LDH) activity. RT-PCR was used to examine the expression of vascular endothelial growth factor mRNA in cells.</p><p><b>RESULTS</b>The monolayer of cultured PMVECs displayed the shape of pavingstone. CD31 antigen and binding BSI results by fluorescence microscope identified the cultured cells were DMVECs. After 24 h cold exposure, the cell morphology of 0 degrees C group was shrunken, the other groups were "Fibroblast-like". The LDH activity (U/L) in the medium of 28 degrees C, 12 degrees C and 0 degrees C groups was 54.17 +/- 3.02, 64.66 +/- 3.03, 82.13 +/- 10.91 respectively, which was significantly higher than that of 37 degrees C group (12.23 +/- 3.0, P < 0.01). The VEGF mRNA expression level was up-regulated in 28 degrees C group and 12 degrees C group versus control group (P < 0.05), but unchanged in 0 degrees C group.</p><p><b>CONCLUSION</b>The rat DMVECs injury severity are deteriorated with temperature decreasing, and VEGF might be involved in the regulation of membrane permeability in this period.</p>

The acclimatization to extreme environments and its physiological mechanisms / 中国应用生理学杂志

Acclimatization is a process of biological adaptation when exposed to environmental factors such as hypoxia, cold and heat for prolonged periods of time, where non-genetical variations play a role in allowing subjects to tolerate hypoxic, cold or hot environments. This review focuses on the characteristics and mechanisms of acclimatization found through major research advances by our institute. First, the mechanisms underlying the acclimatization to extreme environments are complex. In our investigations, the physiological changes of multiple systems including the nervous, circulatory, respiratory, and hemopoietic system were demonstrated when the acclimatization to hypoxia was developed, and the underlying significance of hypoxia-inducible factor-1 (HIF-1) was investigated. Second, it is suggested that the development of acclimatization to extreme environments is complicated. Hypoxia and cold coexist at high altitude. Our investigations revealed the characteristics of negative cross-relationship in the acclimatization to hypoxia and cold. And third, it is interesting for us to understand that acclimatization to extreme environments is transferable among individuals, and the characteristics of heat acclimatization-inducing factor (HAlF) were presented. The above findings will provide a theoretical guidance for protective operations and help to establish a solid foundation for future research related to acclimatization.

Protective effects of SUR2B/Kir6.1 potassium channel opener natakalim against RAVECs injuries induced by hypoxia / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To investigate the protective effects of natakalim against rat aortic vascular endothelial cells (RAVECs) injuries induced by hypoxia and its mechanisms.</p><p><b>METHODS</b>Selecting RAVECs as a cell model injured by hypoxia, these RAVECs were divided into 5 groups: i.e. control group, hypoxia group, natakalim low, medium and high group. The cell survival rate was determined by MTT assay, con was measured using Griess Assay, RT-PCR was used to examine t he expression of intercellular adhesion molecule-1 (ICAM-1), vascular endothelial growth factor (VEGF), endothelin-1 (ET-1) mRNA in RAVEC.</p><p><b>RESULTS</b>Natakalim could reverse hypoxia-induced changes in endothelial cell function, including increased endothelial cell survival rate and level of NO concentration, significantly inhibited the hypoxia-induced endothelial ICAM-1, ET-1, VEGF mRNA expression levels increased.</p><p><b>CONCLUSION</b>Natakalim have protective effects on hypoxia-induced changes in endothelial cell function, increasing of permeation, excess expression of cell adhesion molecules.</p>

Oxidative damage to lung tissue and peripheral blood in endotracheal PM2.5-treated rats / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate the oxidative damage to lung tissue and peripherial blood in PM2.5-treated rats.</p><p><b>METHODS</b>PM2.5 samples were collected using an auto-sampling instrument in summer and winter. Treated samples were endotracheally instilled into rats. Activity of reduced glutathione peroxidase (GSH-Px) and concentration of malondialdehyde (MDA) were used as oxidative damage biomarkers of lung tissue and peripheral blood detected with the biochemical method. DNA migration length (microm) and rate of tail were used as DNA damage biomarkers of lung tissue and peripheral blood detected with the biochemical method.</p><p><b>RESULTS</b>The activity of GSH-Px and the concentration of MDA in lung tissue significantly decreased after exposure to PM2.5 for 7-14 days. In peripheral blood, the concentration of MDA decreased, but the activity of GSH-Px increased 7 and 14 days after experiments. The two indicators had a dose-effect relation and similar changing tendency in lung tissue and peripheral blood. The DNA migration length (microm) and rate of tail in lung tissue and peripheral blood significantly increased 7 and 14 days after exposure to PM2.5. The two indicators had a dose-effect relation and similar changing tendency in lung tissue and peripheral blood.</p><p><b>CONCLUSION</b>PM2.5 has a definite oxidative effect on lung tissue and peripheral blood. The activity of GSH-Px and the concentration of MDA are valuable biomarkers of oxidative lung tissue damage induced by PM2.5. The DNA migration length (microm) and rate of tail are simple and valuable biomarkers of PM2.5-induced DNA damage in lung tissues and peripheral blood. The degree of DNA damage in peripheral blood can predict the degree of DNA damage in lung tissue.</p>

8-hydroxydeoxyguanosine as a biomarker of oxidative DNA damage induced by environmental tobacco side-stream smoke and its mechanism / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To study the genotoxicity effect of environmental tobacco side-stream smokes (ETSS) on oxidative DNA damage and its molecular mechanism.</p><p><b>METHODS</b>DNA adduct 8-hydroxydeoxyguanosine (8-OHdG) was used as a biomarker of oxidative DNA damage. The level of 8-OHdG in DNA exposed to ETSS was detected by high performance liquid chromatography with electrochemical detection. Organic and inorganic components in ETSS were analyzed by gas chromatography-mass spectrum and atomic absorption spectrum respectively.</p><p><b>RESULTS</b>Particle matters (PMs) and volatile organic compounds (VOCs) in ETSS could directly induce oxidative DNA damage and formation of 8-OHdG. There were 123 and 84 kinds of organic components in PMs and VOCs respectively, and 7 kinds of inorganic components in ETSS. Some components, especially quinones and polyphenols in ETSS, could produce free radicals in vitro by auto-oxidation without any biological activity systems, and with the catalytic reaction of metals, the DNA adduct 8-OHdG was produced.</p><p><b>CONCLUSION</b>ETSS have biological oxidative effect on DNA in vitro and in vivo, and expressed direct genotoxicity. 8-OHdG is a valuable biomarker of oxidative DNA damage.</p>

Effects of formaldehyde inhalation on lung of rats / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To analyze protein changes in the lung of Wistar rats exposed to gaseous formaldehyde (FA) at 32-37 mg/m3 for 4 h/day for 15 days using proteomics technique.</p><p><b>METHODS</b>Lung samples were solubilized and separated by two-dimensional electrophoresis (2-DE), and gel patterns were scanned and analyzed for detection of differently expressed protein spots. These protein spots were identified by MALDI-TOF-MS and NCBInr protein database searching.</p><p><b>RESULTS</b>Four proteins were altered significantly in 32-37 mg/m3 FA group, with 3 proteins up-regulated, 1 protein down-regulated. The 4 proteins were identified as aldose reductase, LIM protein, glyceraldehyde-3-phosphate dehydrogenase, and chloride intracellular channel 3.</p><p><b>CONCLUSION</b>The four proteins are related to cell proliferation induced by FA and defense reaction of anti-oxidation. Proteomics is a powerful tool in research of environmental health, and has prospects in search for protein markers for disease diagnosis and monitoring.</p>