The characteristics of vascular endothelial injuries induced by extreme environmental factors / 中国应用生理学杂志

Vascular endothelium plays an important role in regulating vascular homeostasis. Over the past years, it has become clear that endothelial dysfunction is a key event of pathophysiological changes in the initiation and progression of injuries induced by extreme environmental factors. The present review summarizes current understanding of vascular endothelial dysfunction induced by hypoxia, cold and heat, and provides the information for prevention and treatment of environmental exposure injuries.

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.

Immune complex may play an important role in freezing injury of frostbite rats / 中国应用生理学杂志

<p><b>AIM</b>To explore the role of humoral immunity in the pathophysiological process of freezing injury and the possible immune interference in the preventation and treatment of frostbite.</p><p><b>METHODS</b>Severe experimental freezing injury model was made in Wistar rats( n = 20). The concentration of three types of immunoglobulin (IgG, IgA and IgM), two types of complement components (C3 and C4), and circulating immune complex (CIC) were measured respectively before and at 4h, 1d, 3d, and 5d after frostbite. At the same time, the tissue immune complex (TIC) in skeletal muscle and the contents of the red blood cell immune complex (RBC-IC) were also observed and then was the red blood cell immune adherence activity (RCIA).</p><p><b>RESULTS</b>Serum IgG concentration decreased rapidly to the lowest level at 4 h after frostbite IgA concentration dropped to the nadir on 1 day after freezing. Decreases of both immunoglobulins were maintained during the 5 days after frostbite. The fate of both C3 and C4 were the same as those immunoglobulins. Freezing had rather less effect on IgM level. CIC concentration in serum, expressed as the percent of prefreezing increased rapidly and to the zenith on the 3 days post-freezing. By immunofluorescence microscopy, thin continuous linear pattern (IgG) was demonstrated along the SM on the first day post-freezing. Granular and nodular deposits (IgG) appeared along the SM as the time proceeded after frostbite. RBC-IC contents, expressed as the erythrocyte IC rosette rate, increased significantly and to the zenith on the 3 d post-freezing, while RCIA depressed to the nadir at the same time.</p><p><b>CONCLUSION</b>The freezing frostbite is an immune complex related disease which have not been reported by others before.</p>

Changes in expression of apoptosis correlative proteins and HIF-1 during acute hypoxia and hypoxic preconditioning in cultured cardiomyocyte of rat / 中国应用生理学杂志

<p><b>AIM</b>To investigate the relationship between the hypoxia-inducible factor 1(HIF-1) and apoptosis correlative proteins in the cardiomyocyte during hypoxia.</p><p><b>METHODS</b>Rat cardiomyocytes cultured in vitro were divided into normoxia, hypoxia and hypoxic preconditioning groups. The cardiomyocytes in hypoxic preconditioning group were cultured in 1% O2, 5% CO2, 94% N2 for 5 days, 12 h daily before exposed to 0% O2 hypoxia with the hypoxic group. The protein expression of HIF-1alpha, Bcl-2, P53 and Bax in the cardiomyocytes were analysis with Western blot after 48 h 0% O2 hypoxia.</p><p><b>RESULTS</b>With the increment of HIF-1 expression, the Bcl-2 expression was inhibited, the Bax and P53 expression were increased as well during hypoxia. Hypoxic preconditioning could suppress the HIF-1 expression, meanwhile the Bcl-2 expression was elevated, and the Bax expression was decreased.</p><p><b>CONCLUSION</b>HIF-1 may contribute to the regulation of the cardiomyocyte apoptosis with the Bcl-2 family during hypoxia.</p>

Cloning and sequencing of alpha, beta globin coding genes in Tibetans living at high altitude / 中国应用生理学杂志

<p><b>AIM</b>To explore the molecular biological mechanism of hemoglobin with high oxygen affinity in Tibetans by determining the sequence of globin cDNA in Tibetans living at high altitude.</p><p><b>METHODS</b>Total RNA was isolated from human bone marrow samples of three Tibetans who live in Qinghai-Tibet plateau. cDNA fragments coding for alpha and beta genes of human hemoglobin were obtained through RT-PCR and were ligated to plasmid pGEM-T easy vectors, and then the ligation liquid were transformed to Escherichia coli and cloned and sequenced. Nucleotide sequences were compared with GenBank data by BLAST method.</p><p><b>RESULTS</b>sequence of a globin cDNA in Tibetans were the same with the registering globin genes in the GenBank, and Hb Abruzzo (beta143 (H21), His- > Arg) gene mutation, a high oxygen affinity beta globin mutation, was found in one Tibetan' beta goblin coding gene (CAC- > CGC).</p><p><b>CONCLUSION</b>This hemoglobin gene mutation may be associated with high altitude adaptation of Tibetans living at high altitude.</p>

Effects of hypoxia on the secretions of proinflammatory cytokines TNF-alpha and IL-6 in macrophages and its mechanism / 中国应用生理学杂志

<p><b>AIM</b>To investigate the effects of hypoxia on the secretions of proinflammatory cytokines TNF-alpha and IL-6 and to inquire into the mechanism.</p><p><b>METHODS</b>Separated mice abdominal macrophages which were identified with non-specific esterase dye method, and created the hypoxic cultured model. The levels of TNF-alpha and IL-6 in the medium were determined by ELISA method. The mRNA expressions of TNF-alpha and IL-6 were measured by RT-PCR method. NF-kappaB activation was assayed by Western blot method. Finaly, we added cortone (5 microg/ml) to the medium, then observed the secretion levels of TNF-alpha and IL-6 during hypoxia.</p><p><b>RESULTS</b>The secretions of TNF-alpha and IL-6 from Mphi exposed to hypoxia for 12 h were increased significantly compared with control (P < 0.01). The expressions of TNF-alpha mRNA and IL-6 mRNA were enhanced obviously contrasted with control (P < 0.01). NF-kappaB activation in Mphi nuclei was raised at 2 h during hypoxia and persisted to 5 h. We added cortone to the medium and found no significant change in secretion of TNF-alpha and IL-6 during hypoxia.</p><p><b>CONCLUSION</b>Hypoxia could activate NF-kappaB and make it shift to nucleus which promoted the transcriptions and expressions of TNF-alpha and IL-6.</p>

Effects of chronic intermittent hypoxic exposure on myocardial mitochondria ATPase and enzyme complexes of respiratory chain in rats / 中国应用生理学杂志

<p><b>AIM</b>To study the effects of acute and chronic intermittent hypoxic exposure on the activities of Na+ , K+ -ATPase, Ca2 + , Mg2 + -ATPase of myocardial mitochondria and enzyme complexes of respiratory chain in rats.</p><p><b>METHODS</b>The activities of Na , K+ -ATPase, Ca2+ , Mg2+ -ATPase of myocardial mitochondria and enzyme complexes of respiratory chain were investigated after chronic intermittent hypoxic exposure (3000 m and 5000 m, 4 h/d, 2 w respectively) and normoxic rats were exposed to hypoxia (8000 m) for 4h.</p><p><b>RESULTS</b>(1) Hypoxia had no effects on the activity of Na+, K+ -ATPase in myocardial mitochondria of rats. (2) Compared with normoxic control rats, the activity of Ca2+, Mg2+ -ATPase in myocardial mitochondria of acute hypoxic rats was reduced significantly. After chronic intermittent hypoxic exposure, its activity was increased significantly compared with that of acute hypoxic rats. (3) Compared with normoxic control rats, the activities of enzyme complex I, II and IV of respiratory chain in acute hypoxic rats were reduced significantly. After chronic intermittent hypoxic exposure, their activities were increased significantly compared with those of acute hypoxic rats. Under the same experimental conditions, hypoxia had no effects on the activity of enzyme complex III.</p><p><b>CONCLUSION</b>After chronic intermittent hypoxic exposure, the activities of Na+, K+ -ATPase, Ca2+, Mg2+ -ATPase of myocardial mitochondria and enzyme complexes of respiratory chain were increased significantly. These suggested that chronic intermittent hypoxic exposure could improve the functions of respiratory chain in myocardial mitochondria and keep the normal energy metabolism.</p>

Current alteration of K(V) channel in SLE patient's peripheral blood lymphocytes and it's significant / 中国应用生理学杂志

<p><b>AIM</b>To observe the property alteration of K(v) channel in SLE patient's peripheral blood lymphocyte and its significant.</p><p><b>METHODS</b>The patch-clamp technique was used to record the current of K(V) channel in SLE patient's peripheral lymphocyte.</p><p><b>RESULTS</b>The current amplitude of K(V) channel in the SLE patient's lymphocytes decreased, it was (258.6 +/- 112.5) pA in healthy people, but in SLE patient it was (139.4 +/- 58.5) pA (P < 0.05). There was no other changes in the property of channel, include activation potential, inactivation property, channel closing kinetics and its pharmacological property.</p><p><b>CONCLUSION</b>The decline of SLE patient's cell immunity may be related to the decrease of the amplitude of K(V) channel current.</p>