ABSTRACT
This study assessed the effects of a simulated high-altitude environment on the reproductive system of prepubertal male rats and the reversibility of these effects upon return to a normal environment. Three-week-old male Wistar rats were randomly allocated to 4 groups that were exposed to different conditions: a normal environment for 6 weeks and 12 weeks, respectively, hypobaric hypoxia for 6 weeks, and hypobaric hypoxia for 6 weeks followed by a normal environment for 6 weeks. Multiple pathophysiological parameters were evaluated at the histological, endocrine, and molecular levels. Hypobaric hypoxia exposure for 6 weeks during the prepubertal phase significantly altered physiological parameters, body functions, blood indices, and reproductive potential. Six weeks after returning to a normal environment, the damaged reproductive functions partially recovered due to compensatory mechanisms. However, several changes were not reversed after returning to a normal environment for 6 weeks, including disorders of body development and metabolism, increased red blood cells, increased fasting blood glucose, abnormal blood lipid metabolism, decreased testicular and epididymis weights, abnormal reproductive hormone levels, excessive apoptosis of reproductive cells, and decreased sperm concentration. In summary, a hypobaric hypoxic environment significantly impaired the reproductive function of prepubertal male rats, and a return to normal conditions during the postpubertal phase did not fully recover these impairments.
Subject(s)
Rats , Male , Animals , Rats, Wistar , Altitude , Semen/metabolism , Hypoxia/pathology , Genitalia, MaleABSTRACT
OBJECTIVE@#To explore the protective effect and possible mechanisms of bloodletting acupuncture at Jing-well points (BAJP) pre-treatment on acute hypobaric hypoxia (AHH)-induced myocardium injury rat.@*METHODS@#Seventy-five rats were randomly divided into 5 groups by a random number table: a control group (n=15), a model group (n=15), a BAJP group (n=15), a BAJP+3-methyladenine (3-MA) group (n=15), and a BANA (bloodletting at nonacupoint; tail bleeding, n=15) group. Except for the control group, the AHH rat model was established in the other groups, and the corresponding treatment methods were adopted. Enzyme-linked immunosorbent assay (ELISA) was used to detect creatine kinase isoenzyme MB (CK-MB) and cardiac troponins I (CTnI) levels in serum and superoxide dismutase (SOD) and malondialdehyde (MDA) levels in myocardial tissue. Hematoxylin-eosin (HE) staining was used to observe myocardial injury, and terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) staining was used to observe cell apoptosis. Transmission electron microscopy detection was used to observe mitochondrial damage and autophagosomes in the myocardium. The mitochondrial membrane potential of the myocardium was analyzed with the fluorescent dye JC-1. Mitochondrial respiratory chain complex (complex I, III, and IV) activities and ATPase in the myocardium were detected by mitochondrial respiratory chain complex assay kits. Western blot analysis was used to detect the autophagy index and hypoxia inducible factor-1α (HIF-1α)/Bcl-2 and adenovirus E1B 19k Da-interacting protein 3 (BNIP3) signaling.@*RESULTS@#BAJP reduced myocardial injury and inhibited myocardial cell apoptosis in AHH rats. BAJP pretreatment decreased MDA levels and increased SOD levels in AHH rats (all P<0.01). Moreover, BAJP pretreatment increased the mitochondrial membrane potential (P<0.01), mitochondrial respiratory chain complex (complexes I, III, and IV) activities (P<0.01), and mitochondrial ATPase activity in AHH rats (P<0.05). The results from electron microscopy demonstrated that BAJP pretreatment improved mitochondrial swelling and increased the autophagosome number in the myocardium of AHH rats. In addition, BAJP pretreatment activated the HIF-1α/BNIP3 pathway and autophagy. Finally, the results of using 3-MA to inhibit autophagy in BAJP-treated AHH rats showed that suppression of autophagy attenuated the treatment effects of BAJP in AHH rats, further proving that autophagy constitutes a potential target for BAJP treatment of AHH.@*CONCLUSION@#BAJP is an effective treatment for AHH-induced myocardial injury, and the mechanism might involve increasing HIF-1α/BNIP3 signaling-mediated autophagy and decreasing oxidative stress.
Subject(s)
Animals , Rats , Acupuncture Therapy , Altitude , Apoptosis , Autophagy , Bloodletting , Hypoxia/metabolism , Membrane Proteins/pharmacology , Mitochondrial Proteins/pharmacology , Oxidative Stress , Rats, Sprague-DawleyABSTRACT
En las alturas, sobre todo a 2500 metros sobre el nivel del mar, la cantidad absoluta de oxígeno va decreciendo y por lo tanto la cantidad disponible para el intercambio gaseoso disminuye, produciéndose una vasoconstricción hipóxica pulmonar (VHP). La VHP asociada a la hipoxia hipobárica de la altura produce un aumento de la presión pulmonar que es mayor en los lactantes y a mayores alturas. No hay valores únicos de saturación de oxígeno (SatO2) en la altura, porque ésta va disminuyendo según el mayor nivel de altura, aumenta con la edad, y la brecha entre la vigilia y sueño es grande (sobre todo en los primeros meses de vida). El 25% de los niños sanos que viven en altura tienen valores de SatO2 significativamente menores que el 75% restante. Los valores normales de los índices de apnea/hipopnea son distintos a los de nivel del mar. El edema pulmonar de las alturas es una patología frecuente, que se produce por un incremento desproporcionado en la VHP reflejando una hiperactividad del lecho vascular pulmonar ante la exposición aguda a la hipoxia hipobárica. Tiene cuatro fenotipos, es infrecuente en menores de 5 años y rara vez es mortal, la sospecha clínica y el manejo oportuno con oxigeno es la clave. Finalmente, en la altura los valores normales de la función pulmonar de la espirometría, oscilometría de impulso y capacidad de difusión son distintos que a nivel del mar.
At high altitude, especially > 2,500 meters above sea level, the absolute amount of oxygen decreases and therefore the amount available for gas exchange decreases, producing hypoxic pulmonary vasoconstriction (VHP). VHP associated with high-altitude hypobaric hypoxia produces an increase in pulmonary pressure that is greater in infants and at higher altitudes. There are no single values of oxygen saturation (SatO2) at altitude, because it decreases with the highest level of altitude, increases with age, and the gap between wakefulness and sleep is large (especially in the first months of life). Around 25% of healthy children living at altitude have SatO2 values significantly lower than the remaining 75%. The normal values of the apnea/hypopnea indices are different from those at sea level. High altitude pulmonary edema is a frequent pathology that is produced by a disproportionate increase in VHP reflecting hyperactivity of the pulmonary vascular bed in the face of acute exposure to hypobaric hypoxia, it has four phenotypes, it is uncommon in children under 5 years of age, and it is rarely fatal, the clinical suspicion and timely management with oxygen is the key. Finally, at high altitude, the normal values of lung function from spirometry, impulse oscillometry, and diffusing capacity are different from those at sea level.
Subject(s)
Humans , Child , Adolescent , Pulmonary Edema/physiopathology , Altitude , Altitude Sickness/physiopathology , Respiratory Function Tests , Oxygen Saturation , Hypoxia/physiopathologyABSTRACT
The Chilean workforce has over 200,000 people that are intermittently exposed to altitudes over 4000 m. In 2012, the Ministry of Health provided a technical guide for high altitude workers that included a series of actions to mitigate the effects of hypoxia. Previous studies have shown the positive effect of oxygen enrichment at high altitudes. The Atacama Large Millimeter / submillimeter Arrays (ALMA) radiotelescope operate at 5,050 m (Array Operation Site, AOS) and is the only place in the world where Pressure Swing Adsorption (PSA) and Liquid Oxygen technologies have been installed at a large scale. Here we discuss our experience using oxygen supplementation at ALMA, to prevent the malaise and/or risks associated with exposure at 5,050 m. Antenna operators experienced chronic intermittent hypobaric hypoxia (CIHH, shiftwork 8 days HA*6 days rest SL) over 4 years. Studies to define normal O2 saturation values were performed in OSF and AOS by continuous recording during the shift. The outcomes showed no differences between production procedures (PSA or Liquid oxygen) in regulating oxygen availability at AOS facilities. As a result, big-scale installations have difficulties reaching the appropriate oxygen concentration due to leaks in high mobility areas. In addition, the PSA plant requires adequation and maintenance to operate at a very high altitude.
La fuerza laboral chilena cuenta con más de 200.000 personas que están expuestas intermitentemente a altitudes superiores a los 4000 m. En 2012, el Ministerio de Salud entregó una guía técnica para trabajadores de altura que incluía una serie de acciones para mitigar los efectos de la hipoxia. Estudios anteriores han demostrado el efecto positivo del enriquecimiento de oxígeno en altitudes elevadas. El radiotelescopio Atacama Large Millimeter/submillimeter Arrays (ALMA) opera a 5.050 m (Array Operation Site, AOS) y es el único lugar en el mundo donde se han instalado tecnologías de adsorción por cambio de presión (PSA) y oxígeno líquido a gran escala. Aquí discutimos nuestra experiencia usando suplementos de oxígeno en ALMA, para prevenir el malestar y/o los riesgos asociados con la exposición a 5.050 m. Los operadores de antena experimentaron hipoxia hipobárica intermitente crónica (CIHH, trabajo por turnos 8 días HA*6 días descanso SL) durante 4 años. Se realizaron estudios para definir valores normales de saturación de O2 en OSF y AOS mediante registro continuo durante el turno. Los resultados no mostraron diferencias entre los procedimientos de producción (PSA u oxígeno líquido) en la regulación de la disponibilidad de oxígeno en las instalaciones de AOS. Como resultado, las instalaciones a gran escala tienen dificultades para alcanzar la concentración de oxígeno adecuada debido a fugas en áreas de alta movilidad. Además, la planta de PSA requiere de adecuación y mantenimiento para operar a gran altura.
Subject(s)
Humans , Oxygen/administration & dosage , Hypoxia/physiopathology , Blood Pressure/physiology , Models, Molecular , Desert , Absorption , Altitude , TelescopesABSTRACT
Objective:To observe the changes in hippocampus (CA1) and study the effect of chronic intermittent hypobaric hypoxia (CIHH) preconditioning on the memory and cognitive function of mice exposed to the whole brain irradiation.Methods:A total of 48 C57BL/6 male mice were randomly divided into control group, CIHH group, irradiation group (IR group) and CIHH+ IR group. For IR group, the whole brain of mice were irradiated with 10 Gy of 6 MV X-rays in a single fraction. Pretreatment with CIHH was performed by placing mice in a hypobaric chamber before radiation. The mirrors water maze experiment was performed in the four groups to observe the escape latency, the number of crossing platforms and the target quadrant residence time. Nissl staining was used to observe the changes of neuronal cells in hippocampal CA1 region. Immunofluorescence was used to detect the expression of microtubule-associated protein cells (DCX) in the subgranular zone (SGZ) of hippocampal dentate gyrus (DG) to evaluate neurogenesis.Results:After 30 days of whole brain irradiation, the escape latency of mice prolonged gradually, the frequency of crossing platform decreased ( P< 0.001), and the exploration time in the target quadrant decreased ( P<0.001). X-ray irradiation caused disorder of mice neuronal cells, degeneration and necrosis of neuronal cells, and decrease of DCX expression in CA1 region of mice. Compared with IR group, the CIHH+ IR group had shortened the escape latency, increased the frequency of crossing platform [(2.08±0.26) vs. (0.83±0.24), P<0.001], and also increased the exploration time in the target quadrant [(14.12±0.82)s vs. (7.42±0.73)s, P<0.001]. Pretreatment with CIHH also alleviated the deformation and necrosis of neurons in hippocampus, and increased DCX expression in CA1 region. Conclusions:Pretreatment of mice with CIHH plays a protective role in radiation induced hippocampal injury.
ABSTRACT
In order to clarify the influence of acute hypobaric hypoxia on the bile acids of the rat small intestine, we used ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) to identify bile acids in the contents of the small intestine from untreated and acute hypobaric hypoxia-treated rats. Thirty-nine bile acids were detected; PCA and OPLS-DA analysis revealed marked differences in the composition of bile acids between the untreated and the acute hypobaric hypoxia groups. Bile acids were screened with VIP > 1, |log2FC| ≥ 1, P < 0.05, and a total of 7 bile acids with significant differences in content between the two groups were obtained, including 5 conjugated bile acids, 2 unconjugated bile acids; in addition, the content of conjugated bile acids has risen in the treated group. This study demonstrated the influence of high-altitude hypoxic environment on bile acid composition and metabolism in rats. All the animal experiments in this study were approved by the 940th Hospital Ethics Committee (approval No: 2020KYLL012).
ABSTRACT
: To investigate the protective effect of 7-hydroxyethyl chrysin (7-HEC) on rats with exercise-induced fatigue in hypobaric hypoxic condition.Forty healthy male Wistar rats were randomly divided into four groups with 10 rats in each group: control group, model group, chrysin group and 7-HEC group. The rats in control group were raised at local altitude but other three groups were raised in a simulating altitude of for hypobaric hypoxia treatment. The chrysin group and 7-HEC group were given chrysin or 7-HEC by gavage for respectively; while the control group and model group were given the same amount of sterilized water. The weight-bearing swimming tests were performed 3 d later, and the weight-bearing swimming time was documented. After rats were sacrificed, the liver and skeletal muscle tissue samples were taken for pathological examination and determination of lactate, malondialdehyde (MDA), total superoxide dismutase (T-SOD) and glycogen levels. Blood urea nitrogen was also determined. Compared with the model group, weight-bearing swimming times were significantly prolonged in 7-HEC group [ vs. (4.04±1.30) min, <0.01]; pathological changes in liver and skeletal muscle tissue were attenuated; generation rate of blood urea nitrogen vs. 0.60) mmol·L·min, <0.05], lactate [liver: (0.14±0.05) vs. (0.10±0.03) mg·g·min, skeletal muscle: vs. (0.18±] and MDA [liver: (0.48) vs. (0.78±0.28) nmol·mg·min, skeletal muscle: (0.87±0.19) vs. (0.63±0.11) nmol·mg·min] were significantly reduced (all < 0.05); glycogen content [liver: (15.16±2.69) vs. skeletal muscle: (1.46±0.49) vs.0.48) mg/g] and T-SOD [liver: (1.87±0.01) vs. (2.68±0.12) U/mL, skeletal muscle: 0.42) vs. 0.96) U/mL] were significantly improved (all <0.05). 7-HEC has significant protective effect on the rats with exercise-induced fatigue in hypobaric hypoxia condition.
Subject(s)
Animals , Male , Rats , Altitude , Fatigue/prevention & control , Flavonoids , Hypoxia , Rats, WistarABSTRACT
To construct a hypobaric hypoxia-induced cell injury model. Rat pheochromocytoma PC12 cells were randomly divided into control group, normobaric hypoxia group and hypobaric hypoxia group. The cells in control group were cultured at normal condition, while cells in other two groups were cultured in normobaric hypoxia and hypobaric hypoxia conditions, respectively. CCK-8 method was used to detect cell viability to determine the optimal modeling conditions like the oxygen concentration, atmospheric pressure and low-pressure hypoxia time. The contents of lactate dehydrogenase (LDH), superoxide dismutase (SOD) and malondialdehyde (MDA) were detected by microplate method. The apoptosis ratio and cell cycle were analyzed by flow cytometry. The hypobaric hypoxia-induced cell injury model can be established by culturing for 24 h at 1% oxygen concentration and 41 kPa atmospheric pressure. Compared with the control group and normobaric hypoxia group, the activity of LDH and the content of MDA in hypobaric hypoxia group were significantly increased, the activity of SOD was decreased, the percentage of apoptosis was increased (all <0.05), and the cell cycle was arrested in G0/G1 phase. A stable and reliable cell injury model induced by hypobaric hypoxia has been established with PC12 cells, which provides a suitable cell model for the experimental study on nerve injury induced by hypoxia at high altitude.
Subject(s)
Animals , Rats , Cell Hypoxia , Hypoxia , Malondialdehyde , PC12 Cells , Superoxide Dismutase/metabolismABSTRACT
Aim To investigate the effect of chronic intermittent hypobaric hypoxia (CIHH) on relaxation of thoracic aorta rings in male developing rats and the underlying mechanisms. Methods Male neonatal Spra-gue-Dawlay ( SD) rats were randomly divided into eight groups respectively: CIHH treatment group (CIHH), group of one-week post-CIHH (CIHH-pl), group of two-week post-CIHH ( CIHH-p2 ) , group of three-week post-CIHH (CIHH-p3 ) , control group for CIHH (Con), control group for CIHH-pl (Con-1), control group for CIHH-p2 ( Con-2) and control group for CIHH-p3 (Con-3 ). Rats in CIHH groups were put into a hypobaric chamber with the mother rats 1 ~ 3 days before the birth to get a hypobaric hypoxia exposure mimicking 3 km altitude for 42 days, 5 hours daily. Rats in control groups were kept in the same environment as CIHH rats except hypoxia exposure. After anaesthetized with pentobarbital sodium (50 mg • kg-1 i. p. ), the thorax of rats was opened and thoracic aorta rings were made. The artery rings were placed in the bath chamber filled with K-H solution, and the relaxation of artery rings was recorded under normoxia or a-cute hypoxia conditions, respectively. Results (1) Under normoxia condition, the acetylcholine ( ACh)-induced relaxation of thoracic aorta increased obviously in CIHH groups compared with corresponding Con groups ( P < 0. 05 ). ( 2 ) The enhancing effect of CIHH treatment on thoracic aorta could be maintained for at least three weeks (P < 0. 05). (3 ) Under acute hypoxia condition, ACh-induced relaxation of thoracic aorta in each group decreased obviously, but the decrease in CIHH groups was significant less than that in Con groups ( P < 0.05 ). (4) The enhancement of CIHH on relaxation of thoracic aorta could be reversed by indomethacin (Indo), a cyclooxygenase inhibitor, glibenclamide (Gli), a KATP blocker, and Tempo, a free radical scavenger. Conclusions CIHH augments endothelium-dependent relaxation in thoracic aorta of developing rats. Also, CIHH can antagonize the inhibition of acute hypoxia on relaxation of thoracic aorta. The enhancing effect of CIHH treatment may be related with the increase of prostacyclin, the opening of KATP and free radical production.
ABSTRACT
Resumen: El edema pulmonar por mal de altura es una entidad no cardiogénica que se debe a hipoxia hipobárica y falta de adaptación pulmonar en los pacientes que retornan a altitudes mayores de 2.500 m luego de haber permanecido a nivel del mar por varios días. Esta entidad, frecuente en los niños, debido a sus características anatómicas y fisiológicas, suele ser subdiagnosticada o confundida con otras patologías que cursan con insuficiencia respiratoria. Presentamos el caso de un paciente de sexo masculino, 4 años de edad, atendido en Emergencias por dificultad respiratoria severa por mal de altura.
Abstract: Pulmonary edema by altitude sickness is a non-cardiogenic entity, due to lack of pulmonary adaptation and hypobaric hypoxia in patients who return to altitudes higher than 2,500 meters after staying for several days at sea level. This entity is frequent in children, given their physiological and anatomical characteristics. It tends to be underdiagnosed or confused with other pathologies associated with shortness of breath. We present the case of a four-year-old male patient, who attended the emergency department for severe respiratory distress caused by altitude sickness.
Subject(s)
Humans , Male , Child, Preschool , Pulmonary Edema , Child , Altitude SicknessABSTRACT
Hypoxia hypobaric (HH) can cause alterations at testicular level, with temperature increase, intrascrotal alteration and deterioration of spermatogenesis. Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ketoprofen have anti-angiogenic properties, and can decrease testicular abnormalities. The objective of the study was to evaluate the effect of ketoprofen on spermatogenesis of mice exposed to continuous hypobaric hypoxia. 78 Mus musculus CF-1 male mice 3 to 4 months old were used and subjected to HH in chamber at 4200 m. They were divided into 13 groups (G) of 6 animals: 10 with HH cycles (1, 2, 3, 4 and 8, lasting 8.3 days each cycle, two groups each) and 3 in normoxia (Nx). Intraperitoneal ketoprofen 25 mg/kg was administered every 4 days. Euthanasia of these animals was performed at the end of each cycle and in the case the Nx groups at the end of cycles 1, 4 and 8. Percentage of microhematocrit and reticulocytes were measured in blood smears and a morphometric and histopathological analysis of the height of the epithelium, the tubular diameter and the diameter of the tubular lumen was made. It was shown that hematocrit increases continuously up to 8 cycles, while reticulocytes increase up to 3 cycles. Continuous HH decreases the tubular diameter in a sustained manner and proportional to HH cycles, and the height increased only in the groups subjected to 8 cycles. The groups treated with ketoprofen saw a decrease in angiogenesis, presenting some degree of protection at the testicular level.
La hipoxia hipobárica (HH) puede provocar alteraciones a nivel testicular, con aumento de la temperatura, alteración intraescrotal y deterioro de la espermatogénesis. Los antiinflamatorios no esteroidales (AINEs) como el ketoprofeno tienen propiedades antiangiogénicas, pudiendo disminuir las alteraciones testiculares. El objetivo de estudio fue evaluar el efecto del ketoprofeno en la espermatogénesis de ratones expuestos a hipoxia hipobárica continua. Se utilizaron 78 ratones macho Mus musculus CF-1 de 3 a 4 meses de edad y se sometieron a HH en cámara a 4200 m. Se dividieron en 13 grupos (G) de 6 animales: 10 con ciclos de HH (1, 2, 3, 4 y 8, con duración de 8,3 días cada ciclo, dos grupos cada uno) y 3 en normoxia (Nx). Se administró ketoprofeno intraperitoneal 25 mg/kg cada 4 días. La eutanasia de estos animales se realizó al final de cada ciclo y en el caso los grupos Nx al final de los ciclos 1, 4 y 8. Se midió porcentaje de microhematocrito y reticulocitos en frotis de sangre y se hizo un análisis morfométrico e histopatológico de la altura del epitelio, el diámetro tubular y el diámetro de la luz tubular. Se evidenció que el hematocrito aumenta de manera continua hasta los 8 ciclos, en cambio los reticulocitos aumentan hasta los 3 ciclos. La HH continua disminuye el diámetro tubular de forma sostenida y proporcional a los ciclos de HH, y la altura aumentó sólo en los grupos sometidos a 8 ciclos. Los grupos tratados con ketoprofeno se vio una disminución de la angiogénesis, presentando algún grado de protección a nivel testicular.
Subject(s)
Animals , Male , Mice , Spermatogenesis/drug effects , Testis/drug effects , Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Ketoprofen/pharmacology , Hypoxia/physiopathology , Reticulocytes/drug effects , Seminiferous Tubules/drug effects , Testis/injuries , Anti-Inflammatory Agents, Non-Steroidal/administration & dosage , Ketoprofen/administration & dosage , Hematocrit , Neovascularization, PathologicABSTRACT
Background@#Hypobaric hypoxia (HH) exposure at high altitudes can result in a decline in cognitive function, which may have a serious impact on the daily life of people who migrate to high altitudes. However, the specific HH-induced changes in brain function remain unclear. This study explored changes in brain activity in rats exposed to a sustained HH environment using functional magnetic resonance imaging (fMRI).@*Methods@#Healthy male rats (8 weeks old) were randomly divided into a model group and a control group. A rat model of cognitive impairment induced by sustained HH exposure was established. The control and model groups completed training and testing in the Morris water maze (MWM). A two-sample t-test for between-group difference comparisons was performed. Repeated measures analyses of variance for within-group comparisons were performed and post-hoc comparisons were made using the Tukey test. Between-group differences in spontaneous brain activity were assessed using a voxel-wise analysis of resting-state fMRI (rs-fMRI), combined with analyses of the fractional amplitude of low frequency fluctuations (fALFF) in statistical parametric mapping.@*Results@#In the MWM test, the escape latencies of the model group were significantly longer compared with those of the control group (control group vs. model group, day 1: 21.6 ± 3.3 s vs. 40.5 ± 3.4 s, t = -11.282; day 2: 13.5 ± 2.2 s vs. 28.7 ± 5.3 s, t = -7.492; day 3: 10.5 ± 2.8 s vs. 22.6 ± 6.1 s, t = -5.099; day 4: 9.7 ± 2.5 s vs. 18.6 ± 5.2 s, t = -4.363; day 5: 8.8 ± 2.7 s vs. 16.7 ± 5.0 s, t = -3.932; all P < 0.001). Within both groups, the escape latency at day 5 was significantly shorter than those at other time points (control group: F = 57.317, P < 0.001; model group: F = 50.718, P < 0.001). There was no within-group difference in average swimming speed (control group, F = 1.162, P = 0.956; model group, F = 0.091, P = 0.880). Within the model group, the time spent within the original platform quadrant was significantly shorter (control group vs. model group: 36.1 ± 5.7 s vs. 17.8 ± 4.3 s, t = 7.249, P < 0.001) and the frequency of crossing the original platform quadrant was significantly reduced (control group vs. model group: 6.4 ± 1.9 s vs. 2.0 ± 0.8 s, t = 6.037, P < 0.001) compared with the control group. In the rs-fMRI study, compared with the control group, rats in the model group showed widespread reductions in fALFF values throughout the brain.@*Conclusions@#The abnormalities in spontaneous brain activity indicated by the fALFF measurements may reflect changes in brain function after HH exposure. This widespread abnormal brain activity may help to explain and to provide new insights into the mechanism underlying the impairment of brain function under sustained exposure to high altitudes.
ABSTRACT
OBJECTIVE： To study the improving effects of echinacoside （ECH） on spatial cognitive function in mice under hypobaric hypoxia environment and its mechanism. METHODS： Totally 60 mice were randomly divided into blank group （normal saline）， model group （normal saline）， positive group （Ginkgo leaf extract tablet，100 mg/kg） and ECH low-dose， medium-dose and high-dose groups （50， 75， 100 mg/kg）， with 10 mice in each group. Except for blank group， other groups were cultured in hypobaric oxygen chamber to simulate hypobaric hypoxia； they were given relevant medicine intragastrically once a day， for consecutive 7 d （Placing into hypobaric oxygen chamber immediately after medication）. Using the times of horizontal and vertical activities of mice in 2 min as index， negative emotions and spatial cognitive function were evaluated. Histopathological changes of hippocampus in mice were observed by microscopy after HE staining. The levels of SOD， CAT， GSH-Px and MDA in hippocampal tissue of mice were detected. RESULTS： Compared with blank group， the times of horizontal activities， MDA level were increased significantly in model group （P＜0.05）， while the times of vertical activities， the levels of SOD， CAT and GSH-Px were decreased significantly （P＜0.05）； the pyramidal cells in the CA1 area of the hippocampal tissue were arranged loosely， and many pyramidal cells were compressed and stained deeply. Compared with model group， the times of horizontal activities and MDA level were decreased significantly in positive group and ECH high-dose group （P＜0.05）， while the times of vertical activities， the levels of SOD， CAT and GSH-Px were increased significantly （P＜0.05）； the pyramidal cells in the CA1 region of the hippocampal tissue were abundant and closely arranged， and a few of them are constricted and deeply stained. CONCLUSIONS： ECH can improve spatial cognitive impairment of mice under hypobaric hypoxia environment， the mechanism of which may be associated with up-regulation of SOD， CAT and GSH-Px， down-regulation of MDA in the hippocampal tissue.
ABSTRACT
Chronic intermittent hypobaric hypoxia (CIHH) is known to have an anti-hypertensive effect, which might be related to modulation of the baroreflex in rats with renal vascular hypertension (RVH). In this study, RVH was induced by the 2-kidney-1-clip method (2K1C) in adult male Sprague-Dawley rats. The rats were then treated with hypobaric hypoxia simulating 5000 m altitude for 6 h/day for 28 days. The arterial blood pressure (ABP), heart rate (HR), and renal sympathetic nerve activity (RSNA) were measured before and after microinjection of L-arginine into the nucleus tractus solitarii (NTS) in anesthetized rats. Evoked excitatory postsynaptic currents (eEPSCs) and spontaneous EPSCs (sEPSCs) were recorded in anterogradely-labeled NTS neurons receiving baroreceptor afferents. We measured the protein expression of neuronal nitric oxide synthase (nNOS) and endothelial NOS (eNOS) in the NTS. The results showed that the ABP in RVH rats was significantly lower after CIHH treatment. The inhibition of ABP, HR, and RSNA induced by L-arginine was less in RVH rats than in sham rats, and greater in the CIHH-treated RVH rats than the untreated RVH rats. The eEPSC amplitude in NTS neurons receiving baroreceptor afferents was lower in the RVH rats than in the sham rats and recovered after CIHH. The protein expression of nNOS and eNOS in the NTS was lower in the RVH rats than in the sham rats and this decrease was reversed by CIHH. In short, CIHH treatment decreases ABP in RVH rats via up-regulating NOS expression in the NTS.
Subject(s)
Animals , Male , Baroreflex , Physiology , Blood Pressure , Hypertension , Metabolism , Hypoxia , Kidney , Metabolism , Nitric Oxide Synthase Type I , Metabolism , Rats, Sprague-Dawley , Solitary Nucleus , MetabolismABSTRACT
RESUMEN Introducción En Chile, los trabajadores mineros están expuestos a condiciones laborales y ambientales particulares. Sin embargo, la normativa actual no considera estas condicionantes para evaluar el estado nutricional y riesgo cardiovascular de esta población. Objetivo Describir indicadores antropométricos de trabajadores mineros de la Región de Coquimbo, expuestos a un ambiente hipóxico hipobárico de manera crónica intermitente a una altitud moderada entre 0 a 2500 m. Metodología Se evaluaron 221 trabajadores a 0 m, 1600 m, y 2500 m. Se les midió peso, talla, pliegues cutáneos, perímetros de cintura y cuello. Con estas mediciones se determinó estado nutricional, composición corporal e indicadores antropométricos relacionados con riesgo cardiovascular. Resultados Los indicadores presentaron valores promedios superiores a la media nacional. Más aún, al separar los resultados por cota altitudinal, estos valores presentan un aumento a mayor altitud. Conclusión Este estudio mostró una alteración en los indicadores antropométricos, estado nutricional y composición corporal, con la altitud. Futuros estudios con un mayor tamaño muestral son necesarios para clarificar estos hallazgos.
ABSTRACT Introduction In Chile, miners are exposed to specific labor and environmental conditions. However, current regulations do not consider these conditions in the assessment of nutritional status and cardiovascular risk of this population. Objective To describe anthropometric indicators of miners in the Coquimbo Region who are exposed to chronic intermittent hypobaric hypoxia at moderate altitudes (between 0 and 2500 m). Methodology We evaluated 221 workers at 0 m, 1600 m, and 2500 m. We measured weight, height, skin fold, waist and neck circumference. With these measurements, we determined nutritional status, body composition and anthropometric indicators related to cardiovascular risk. Results The assessed indicators showed average values higher than national ones. Furthermore, values increased by altitude. Conclusion This study showed an alteration with the altitude in the anthropometric indicators, nutritional condition and body composition. Further studies with a high sample size are necessary to clarify these findings.
Subject(s)
Nutritional Status , Miners , Hypoxia , Body Composition , AnthropometryABSTRACT
·High altitude retinopathy (HAR) is the pathological changes of retina and optic caused by hypobaric hypoxia when the body is in high altitude environment, and HAR is the major cause of visual loss for the plainsmen who went to high attitude area. With the development of economy and tourism of plateau regions, the prevalence of HAR has recently been increasing for more and more people going to high altitude areas. Currently, it is reported that the pathogenesis of HAR involves a host of mechanisms, including the integrity damage of blood-retinal barrier (BRB),retinal neuron injury,inflammatory mediators and cytokines produced excessively, retinal blood vessels regulate dysfunction, and hemodynamics abnormality,and the synergistic action between them. In this review, we report the findings from current studies on the pathogenesis of HAR, contributing to further studies and diagnosis and treatment.
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OBJECTIVE: Normobaric (NH) and hypobaric hypoxia (HH) are associated with acute mountain sickness (AMS) and cognitive dysfunction. Only few variables, like heart-rate-variability, are correlated with AMS. However, prediction of AMS remains difficult. We therefore designed an expedition-study with healthy volunteers in NH/HH to investigate additional non-invasive hemodynamic variables associated with AMS. METHODS: Eleven healthy subjects were examined in NH (FiO2 13.1%; equivalent of 3.883 m a.s.l; duration 4 h) and HH (3.883 m a.s.l.; duration 24 h) before and after an exercise of 120 min. Changes in parameters of electrical cardiometry (cardiac index (CI), left-ventricular ejection time (LVET), stroke volume (SV), index of contractility (ICON)), near-infrared spectroscopy (cerebral oxygenation, rScO2), Lake-Louise-Score (LLS) and cognitive function tests were assessed. One-Way-ANOVA, Wilcoxon matched-pairs test, Spearman’s-correlation-analysis and Student’s t-test were performed. RESULTS: HH increased heart rate (HR), mean arterial pressure (MAP) and CI and decreased LVET, SV and ICON, whereas NH increased HR and decreased LVET. In both NH and HH cerebral oxygenation decreased and LLS increased significantly. After 24 h in HH, 6 of 11 subjects (54.6%) developed AMS. LLS remained increased until 24 h in HH, whereas cognitive function remained unaltered. In HH, HR and LLS were inversely correlated (r = − 0.692; p < 0.05). More importantly, the rScO2-decrease after exercise in NH significantly correlated with LLS after 24 h in HH (r = − 0.971; p < 0.01) and rScO2 correlated significantly with HR (r = 0.802; p < 0.01), CI (r = 0.682; p < 0.05) and SV (r = 0.709; p < 0.05) after exercise in HH. CONCLUSIONS: Both acute NH and HH altered hemodynamic and cerebral oxygenation and induced AMS. Subjects, who adapted their CI had higher rScO2 and lower LLS. Furthermore, rScO2 after exercise under normobaric conditions was associated with AMS at high altitudes.
Subject(s)
Altitude , Altitude Sickness , Hypoxia , Arterial Pressure , Cognition , Healthy Volunteers , Heart Rate , Hemodynamics , Oxygen , Spectroscopy, Near-Infrared , Stroke VolumeABSTRACT
La obesidad es considerada como una epidemia. Es un factor de riesgo para el desarrollo de diabetes mellitus de tipo 2 y otras comorbilidades. Se revisa la prevalencia de obesidad en la altura a nivel nacional y mundial, así como también la relación entre hipoxia crónica y aguda con la obesidad.
Obesity is considered an epidemic disease. It is a risk factor for diabetes mellitus type 2 and some other metabolic and neoplastic disorders. The national and worldwide prevalence of obesity at high altitude and the relation between obesity and chronic and acute hypoxia at high altitude are revised.
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Objective To investigate the effect of hypobaric hypoxia and cold exposure on brown adipose tissue in mice. Methods Twenty-four 6-week old SPF C57BL/6 male mice were randomly divided into 4 groups with 6 mice in each group: normal atmospheric pressure and temperature group ( 18~22℃, 20~60 m ) ( NTNP ) , low atmospheric pressure and normal temperature group ( 18~22℃, altitude of 5000 m ) ( NTLP ) , normal atmospheric pressure and cold exposure group(0~6℃, altitude of 20 ~60 m)(LTNP), low atmospheric pressure and cold exposure group(0 ~6℃, altitude of 5,000 m)(LTLP). The experimental period was 4 weeks. The body weight was measured at the beginning and end of the experiment. By the end of the four-week trial, the back and inguinal fat were dissected and observed by histology using HE staining. The expression of UCP-1 as the marker of brown adipose tissue in the back fat was detected by qPCR and western blot. Results The body weight gain of NTNP group was higher ( P< 0. 05 ) than the other three groups. Meanwhile, the color of the back and groin fat tissue of mice of LTNP and LTLP groups were darker, the blood supply in mice of these two groups was richer than the NTLP group. The volume of adipose tissue of NTNP group was higher than others. The histology showed that the back adipose cells of the mice were smaller and darker and full of multilocular lipid droplets, exhibiting a typical morphology of brown fat cells. Compared with the NTNP and NTLP groups, the mRNA and protein levels of UCP-1 were higher under cold exposure, while low atmospheric pressure had a tendency to reduce the mRNA expression of UCP-1. Conclusions The formation of brown fat is affected by the imitated conditions of low atmospheric pressure and cold exposure, and is more closely related to the decresed temperature.
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Objective To investigate the effects of chronic hypobaric hypoxia on COX1 protein and oxidative stress in lung tissue. Methods Rats were randomly divided into normoxia group (1 500 m)and hypoxia group (4 300 m). The rats in hypoxia group were sampled after exposure to hypoxia for 30 days. The COX1 protein in lung tissue of rats was determined by Western blot method; HIF-1αlevel in lung tissue and serum, ROS in plas-ma and SOD, CAT enzyme in lung tissue were determined by ELISA method; PAP of rats were determined by physiological signal acquisition system. Results HIF-1 protein express in serum and lung tissue of rats in hypoxia group was significantly higher than that of the normoxia group (P<0.01), the content of ROS was significantly lower than that of the normoxia group (P<0.01), the expression of COX1 protein in lung tissues of hypoxia group was significantly decreased(P<0.01),serum total antioxidant capacity was elevated in hypoxia group(P<0.01).Conclusions The effects of chronic hypobaric hypoxia on lung tissue may be caused by direct injury, not only by oxidative stress.