The intervention effect of Tibetan medicine Siwei Huangqi powder on hypoxic pulmonary hypertension through autophagy signaling pathway induced by AMPK protein / 中国药理学通报

Aim To explore the mechanism of Tibetan medicine Siwei Huangqi powder(SW)in reducing hypoxic pulmonary hypertension. Methods A total of 110 Wistar rats were randomly divided into normoxia control group,hypoxic control group and hypoxic drug group. The two hypoxic groups were divided into 1,3,7,15 and 30 day group according to the exposure time of hypoxic,10 groups in total. The normoxia control group was placed in the atmospheric environment at an altitude of 2 260 meters without intervention; 10 hypoxic groups were placed in a hypobaric hypoxic chamber with a simulated altitude of 5 000 meters. The hypoxic drug group was given SW suspension(0.42 g/100 g)by gavage,and the hypoxic control group was given normal saline by gavage,once a day. The Ppa and RV/(LV+S)were measured at the corresponding time points in each group; the levels of p-AMPK,ULK-1 and LC3 /LC3 Ⅱ protein in lung tissues were measured by WB method. Results Compared with normoxia control group,the ratio of PA and RV/(LV + s)in hypoxic control group increased gradually with the extension of hypoxic exposure time,which was consistent with the thickness of pulmonary artery smooth muscle layer and the changes of pulmonary tissue subcellular organelles. The expression level of p-AMPK protein in lung tissues was also slightly up-regulated(P<0.05),and ULK-1 and LC3 Ⅱ were significantly up-regulated(P<0.01),especially in acute hypoxic. Compared with the hypoxic control group,the increase of Ppa and the thickening of pulmonary artery smooth muscle layer in the hypoxic drug group were significantly reduced(P<0.050.01),while the expression levels of p-AMPK,ULK-1 and LC3 Ⅱ proteins in lung tissues increased with the extension of hypoxic exposure time(P<0.050.001),especially in chronic hypoxic. Conclusion SW can inhibit hypoxic pulmonary hypertension by up-regulating AMPK autophagy signaling pathway.

Neurological adaptations to hypoxia in Tibetan antelope (Pantholops hodgsonii) with a view of molecular biology of respiratory globin-neuroglobin / 中国应用生理学杂志

Neuroglobin (Ngb) is a respiratory protein that is preferentially expressed in brain of mouse and man. In this article, Tibetan antelope, living at altitude of 3 000-5 000 m for millions of years, was selected as the model of hypoxia-tolerant adaptation species. Using reverse transcription polymerase chain reaction (RT-PCR) and Western blot techniques, expression of Ngb gene was amplified and analyzed in antelope brain tissue. Our results showed that Ngb homology protein in Tibetan antelope was identified with more sequence similarity with cattle (96%), sheep (95%), and human (95%). We detected that there were some mutations occurred in the Open Reading Frame of Ngb in Tibetan antelope compared with sheep. Phylogenetic analysis of Ngb chain showed that it was closer to cattle than the others. This study suggests possible roles of central nervous system enriched Ngb in adaptation of Tibetan antelope to extremely high altitude.

Energy power in mountains: difference in metabolism pattern results in different adaption traits in Tibetans / 中国应用生理学杂志

Energy metabolism plays an important role in life survival for species living in high altitude hypoxia condition. Air-breathing organisms require oxygen to create energy. Tibetans are the well-adapted highlanders in Qinghai-Tibetan Plateau. It was thought that different metabolic approaches could lead to different adaptation traits to high altitude hypoxia. Recently identified hypoxia inducible factors pathway regulators, endothelial PAS domain protein1 (EPAS1)/HIF-2a and PPARA, were involved in decreasing hemoglobin concentrations in Tibetans. Because EPAS1 and PPARA also modulated the energy metabolism during hypoxia, we hypothesized that positive selected EPAS1 and PPARA genes were also involved in unique energy metabolisms in Tibetans. In this brief review, we take a look into genetic determinations to energy metabolisms for hypoxia adaptations traits in Tibetans and mal-adaptive conditions such as high altitude diseases.

Hypobaric hypoxia induces high expression of neuroglobin in rat cerebral cortical neurons / 中华神经医学杂志

Objective To explore the changes in neuroglobin(NGB)expression in rat cerebral cortex induced by acute and chronic hypoxia at high altitude.Methods Seventy SD rats were randomly divided into normal control and experimental groups,and in the latter group,the rats kept in a high-altitude research base in Kekexili(4600 m),while the control rats were kept in a facility at the altitude of 2295 m.The rats in the experimental group were divided into 6 groups with the exposure time of 12,24,48,72 h,1 week and 1 month.An oximeter was used to measure the SaO2 level.Semi-quantitative PCR and Western blotting were performed to detect the expression levels of NGB mRNA and protein in the cortical neurons of the rats after the exposure.Results After explosure of the rats to hypoxia at high altitude for 12h,the SaO2 was lowered to(70.70±2.83)%and increased gradually as exposure time prolonged,but remained lower than that in the control group throughout the exposure.RT-PCR showed a rapid increase of NGB mRNA expression after 24-h exposure to hypoxia,followed by gradual decrease till recovery of the normal level at 1 week;the expression slowly increased after 1 week and maintained a high level till 1 months.showing significant difference from that in the control group(P＜0.05).Western blotting showed an identical pattem of NGG protein expression alterations during the experiment.Conclusion NGB expressions in the cerebral cortex increase significantly after acute and chronic hypoxia at an altitude of 4600 m to enhance the tolerance to hypobaric hypoxia,suggesting the possible role of NGB as an important endogenous mechanism for protecting the neural tissues against hypoxic injuries.

The dynamic changing profiles of peripheral white blood cell telomere length in populations of different ages living at different altitude areas / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the relationship between the length of telomere DNA and age at different altitude areas.</p><p><b>METHODS</b>All 172 peripheral blood samples were randomly selected from healthy individuals of different ages from 25 to 65 years old. High altitude group (47 males, 48 females) living at an altitude of 4380 m (HA group), sea level group (39 males, 38 females) living at an altitude of 43 m (SL group). The terminal restriction fragment (TRF) length of telomere DNA was measured by Southern blotting analysis. The plasma levels of malondialdehyde (MDA) and superoxide dismutase (SOD) were assayed.</p><p><b>RESULTS</b>Average TRF lengths of males and females in HA groups were 10.45 +/- 1.35 and 10.50 +/- 1.45. Average TRF lengths of males and females in SL groups were 11.29 +/- 1.10 and 11.31 +/- 1.13. A negative correlation was shown between the average TRF length and age of males in two groups (P < 0.01). This was also the case for females. ANOVA test was used to analyze the difference between TRF length and gender at different ages (P < 0.001). It was shown that there was significant difference in TRF length between the male (25 years old and 55 years old) and female (25 years old and 55 years old) in two groups at different ages (P < 0.05). The plasma levels of SOD and MDA were significant different between HA groups and SL groups (25-44 years old groups/45-65 years old groups) (P < 0.05).</p><p><b>CONCLUSION</b>Obviously shortening of telomere was observed by increasing of ages in high altitude groups. There was a negative correlation between the length of telomere DNA and ages. Telomere shortening became more obviously in high altitude group than in sea level group in keeping with the age increases.</p>

Electrophysiological study on rat conduit pulmonary artery smooth muscle cells under normoxia and acute hypoxia / 生理学报

The present study was designed to investigate the electrophysiological characteristics of rat conduit pulmonary artery smooth muscle cells (PASMCs) and the response to acute hypoxia. PASMCs of the 1st to 2nd order branches in the conduit pulmonary arteries were obtained by enzymatic isolation. The PASMCs were divided into acute hypoxia preconditioned group and normoxia group. Hypoxia solutions were achieved by bubbling with 5% CO2 plus 95% N2 for at least 30 min before cell perfusion. Potassium currents were compared between these two groups using whole-cell patch clamp technique. The total outward current of PASMCs was measured under normoxia condition when iBTX [specific blocking agent of large conductance Ca-activated K(+) (BK(Ca)) channel] and 4-AP [specific blocking agent of delayed rectifier K(+) (K(DR)) channel] were added consequently into bath solution. PASMCs were classified into three types according to their size, shape and electrophysiological characteristics. Type I cells are the smallest with spindle shape, smooth surface and discrete perinuclear bulge. Type II cells show the biggest size with banana-like appearance. Type III cells have the similar size with type I, and present intermediary shape between type I and type II. iBTX had little effect on the total outward current in type I cells, while 4-AP almost completely blocked it. Most of the total outward current in type II cells was inhibited by iBTX, and the remaining was sensitive to 4-AP. In type III cells, the total outward current was sensitive to both iBTX and 4-AP. Acute hypoxia reduced the current in all three types of cells: (1614.8+/-62.5) pA to (892.4+/-33.6) pA for type I cells (P<0.01); (438.3+/-42.8) pA to (277.5+/-44.7) pA for type II cells (P<0.01); (1 042.0+/-37.2) pA to (613.6+/-23.8) pA for type III (P<0.01), and raised the resting membrane potentials (E(m)) in all these three types of cells: (-41.6+/-1.6) mV to (-18.6+/-1.5) mV (P<0.01), (-42.3+/-3.8) mV to (-30.6+/-3.0) mV (P<0.01), (-43.3+/-1.6) mV to (-28.4+/-1.4) mV (P<0.01), for type I, II, III cells, respectively. These results suggest that acute hypoxia suppresses the potassium current and improves the E(m) in PASMCs. These effects may be involved in the modulation of constriction/relaxation of conduit artery under acute hypoxia. Different distribution of K(DR) and BK(Ca) channels in these three types of PASMCs might account for their different constriction/relaxation response to acute hypoxia.