Objective:Plateau hypoxia exposure causes changes in pharmacokinetic parameters and cerebral-blood distribution of drugs,including many substrates of P-glycoprotein(P-gp).Levetiracetam,a kind of antiepileptic drugs,is a substrate of P-gp.Whether plateau hypoxia exposure changes its pharmacokinetic characteristics and cerebral-blood distribution remains unclear.This study aims to investigate the effects of plateau hypoxia on the pharmacokinetics and cerebra-blood distribution of levetiracetam. Methods:Wistar rats were divided into a low-altitude control group,a high-altitude group,a solvent group,and a P-gp induction group.After 24 h of exposure at altitude of 4 010 m,rats in the high-altitude group were given levetiracetam orally or intravenously.The plasma was respectively collected at 0.083,0.25,0.5,0.83,1.25,2,4,6,8,10,12,and 24 h after oral administration of the drug,while both plasma and brain were respectively collected at 5,45,60,120 and 240 min after intravenous injection.After 3 days administration of dexamethasone,plasma and brain of rats in the P-gp induction group were collected at 120 min after intravenously giving levetiracetam.Plasma and brain concentrations of the drug were determined by high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS).The expression of P-gp in blood-brain barrier was detected by Western blotting. Results:Compared with the low-altitude control group,the area under the curve(AUC)and mean residence time(MRT)of levetiracetam were respectively decreased by 14.69%(P<0.01)and 15.42%(P<0.01),while the clearance(CL)was increased by 16.67%(P<0.01)in the high-altitude group.The ratio of brain/blood plasma drug concentration was decreased by 22.82%(P<0.05),12.42%(P<0.05),17.40%(P<0.01),and 13.22%(P<0.01)at 5,45,120,and 240 min after injection,respectively.The expression of P-gp on the blood-brain barrier was increased by 86.3%(P<0.05).Compared with the solvent control group,the expression of P-gp on the blood-brain barrier in the P-gp induction group was increased by 56.3%(P<0.05),the ratio of brain/blood plasma drug concentration was decreased by 19.3%(P<0.05). Conclusion:After acute plateau hypoxia exposure,the pharmacokinetic of levetiracetam in rats are altered,and the cerebral-blood distribution of the drug in rats is decreased,which may be related to the up-regulation of P-gp expression on the blood-brain barrier.

Solenopsis invicta is a kind of invasive pest that causes serious damage to local agriculture, environment, and human health. They attack mainly with venom within stingers. Those who are allergic to the venom would suffer a systemic anaphylaxis, even fatal shock, after being stinged by these ants. Many studies reveal that their venom is mainly composed by water, insoluble alkaloids and trace proteins, within which alkaloids are the main cause of burning sensation and blisters, while allergic reactions are caused by proteins or peptides. The research progress of toxic substances in the venom of Solenopsis invicta as well as the roles and functions of each component were reviewed in this paper.

Due to factors such as low pressure, low oxygen and cold in the plateau environment, people who enter the plateau rapidly are susceptible to digestive system diseases, such as upper abdominal pain, loss of appetite, nausea and vomiting and other gastrointestinal dysfunction, which seriously affect the health and work ability of people who enter the plateau rapidly. The gastrointestinal dysfunction caused by the rapid advance to the plateau is mainly reflected in three aspects: gastrointestinal motility dysfunction, impaired mucosal barrier function, and intestinal flora imbalance. At present, the pathogenesis of gastrointestinal dysfunction is still not very clear, and there are fewer drugs for targeted prevention and treatment. Gastrointestinal hormones, oxygen free radicals, inflammatory factors, intestinal flora and other factors, as well as the protective effects of related drugs were reviewed in this paper to provide treatment options and theoretical basis for the prevention and treatment of the gastrointestinal emergency response caused by entering the plateau.

OBJECTIVES: Hypoxia can alter the oral bioavailability of drugs, including various substrates (drugs) of P-glycoprotein (P-gp), suggesting that hypoxia may affect the function of P-gp in intestinal epithelial cells. Currently, Caco-2 monolayer model is the classic model for studying the function of intestinal epithelial P-gp. This study combines the Caco-2 monolayer model with hypoxia to investigate the effects of hypoxia on the expression and function of P-gp in Caco-2 cells, which helps to elucidate the mechanism of changes in drug transport on intestinal epithelial cells in high-altitude hypoxia environment. METHODS: Normally cultured Caco-2 cells were cultured in 1% oxygen concentration for 24, 48, and 72 h, respectively. After the extraction of the membrane proteins, the levels of P-gp were measured by Western blotting. The hypoxia time, with the most significant change of P-gp expression, was selected as the subsequent study condition. After culturing Caco-2 cells in transwell cells for 21 days and establishing a Caco-2 monolayer model, they were divided into a normoxic control group and a hypoxic group. The normoxic control group was continuously cultured in normal condition for 72 h, while the hypoxic group was incubated for 72 h in 1% oxygen concentration. The integrity and polarability of Caco-2 cells monolayer were evaluated by transepithelial electrical resistance (TEER), apparent permeability (Papp) of lucifer yellow, the activity of alkaline phosphatase (AKP), and microvilli morphology and tight junction structure under transmission electron microscope. Then, the Papp of rhodamine 123 (Rh123), a kind of P-gp specific substrate, was detected and the efflux rate was calculated. The Caco-2 cell monolayer, culturing at plastic flasks, was incubated for 72 h in 1% oxygen concentration, the expression level of P-gp was detected. RESULTS: P-gp was decreased in Caco-2 cells with 1% oxygen concentration, especially the duration of 72 h (P<0.01). In hypoxic group, the TEER of monolayer was more than 400 Ω·cm², the Papp of lucifer yellow was less than 5×10^-7 cm/s, and the ratio of AKP activity between apical side and basal side was greater than 3. The establishment of Caco-2 monolayer model was successful, and hypoxia treatment did not affect the integrity and polarization state of the model. Compared with the normoxic control group, the efflux rate of Rh123 was significantly reduced in Caco-2 cell monolayer of the hypoxic group (P<0.01). Hypoxia reduced the expression of P-gp in Caco-2 cell monolayer (P<0.01). CONCLUSIONS Hypoxia inhibits P-gp function in Caco-2 cells, which may be related to the decreased P-gp level.
Humans ; ATP Binding Cassette Transporter, Subfamily B, Member 1 ; Caco-2 Cells ; ATP Binding Cassette Transporter, Subfamily B ; Hypoxia ; Oxygen

Hippo signal pathway is one of the main signal pathways regulating cell proliferation and apoptosis in multicellular animals, which plays a vital role in the maintenance of tissue homeostasis and the regulation of organ growth. Most mammals have limited regenerative potential, and recent studies have shown that Hippo signal pathway is critical in the regeneration of various tissues and organs. The role of Hippo signaling pathway in organ regeneration and the research progress of related targets were introduced, the mechanism of Hippo signaling pathway promoting regeneration analyzes were aralyzed in this review, which provide theoretical reference for the treatment of diseases related to organ regeneration.

Areca catechu L. medicinal materials and their preparations are widely used in clinical practice. Betelnut polyphenol is one of the main chemical components with antioxidant, anti-inflammatory, and antibacterial effects. With continuous increase of high altitude activities, tissue oxidative damage caused by high altitude hypoxia seriously affects the ability to work, and the studies on anti-hypoxia drugs are particularly important. Recent studies have shown that betelnut polyphenols have protective effects on oxidative stress injury caused by hypoxia via improving blood gas index of hypoxic organism, increasing superoxide dismutase glutathione catalase activity, and scavenging excessive free radicals. The effects of betelnut polyphenols against hypoxia and oxidative damage protection suggest that betelnut polyphenols can be used as potential anti-hypoxia drugs and posses clinical prospects.
Antioxidants/pharmacology* ; Areca/chemistry* ; Humans ; Hypoxia ; Oxidative Stress ; Polyphenols/pharmacology* ; Superoxide Dismutase/metabolism*

OBJECTIVES: The plateau environment is characterized by low oxygen partial pressure, leading to the reduction of oxygen carrying capacity in alveoli and the reduction of available oxygen in tissues, and thus causing tissue damage. Cilostazol is a phosphodiesterase III inhibitor that has been reported to increase the oxygen release of hemoglobin (Hb) in tissues. This study aims to explore the anti-hypoxic activity of cilostazol and its anti-hypoxic effect. METHODS: A total of 40 male BALB/C mice were randomly divided into a low-dose cilostazol (6.5 mg/kg) group, a medium-dose (13 mg/kg) group, a high-dose (26 mg/kg) group, and a control group. The atmospheric airtight hypoxia experiment was used to investigate the anti-hypoxic activity of cilostazol and to screen the optimal dosage. Twenty-four male Wistar rats were randomly divided into a normoxia control group, a hypoxia model group, an acetazolamide (22.33 mg/kg) group, and a cilostazol (9 mg/kg) group. After 3 days of hypoxia in the 4 010 m high altitude, blood from the abdominal aorta was collected to determine blood gas indicators, the levels of IL-6 and TNF-α in plasma were determined by enzyme-linked immunosorbent assay, and the levels of malondialdehyde (MDA), superoxide dismutase (SOD), and glutataione (GSH) were measured. The degree of pathological damage for rat tissues was observed with HE staining. RESULTS: Compared with the control group, the survival time of mice in the low, medium, and high dose group of cilostazol was significantly prolonged, and the survival time of mice in the medium dose group was the longest, with an extension rate at 29.34%, so the medium dose was the best dose. Compared with the hypoxia model group, the P50 (oxygen partial pressure at Hb oxygen saturation of 50%) value of rats in the cilostazol group was significantly increased by 1.03%; Hb and Hct were significantly reduced by 8.46% and 8.43%, and the levels of IL-6 and TNF-α in plasma were reduced by 50.65% and 30.77%. The MDA contents in heart, brain, lung, liver, and kidney tissues were reduced by 37.12%, 29.55%, 25.00%, 39.34%, and 21.47%, respectively. The SOD activities were increased by 94.93%, 9.14%, 9.42%, 13.29%, and 20.80%, respectively. The GSH contents were increased by 95.24%, 28.62%, 28.57%, 20.80%, and 44.00%, respectively. The results of HE staining showed that compared with the hypoxia model group, cilostazol significantly improved the damage of heart, lung, and kidney tissues in rats after hypoxia. CONCLUSIONS Cilostazol can significantly improve the oxidative stress and inflammatory reaction caused by rapid altitude hypoxia, and it has a significant protective effect on tissue damage caused by hypoxia, suggesting that it has obvious anti-hypoxic activity.
Altitude Sickness ; Animals ; Cilostazol/therapeutic use* ; Hypoxia/drug therapy* ; Interleukin-6/pharmacology* ; Male ; Mice ; Mice, Inbred BALB C ; Oxidative Stress ; Oxygen ; Rats ; Rats, Wistar ; Superoxide Dismutase/metabolism* ; Tumor Necrosis Factor-alpha/pharmacology*

Metformin is the most common first-line oral hypoglycemic drug ，but there are large individual differences in pharmacokinetic parameters and pharmacodynamics during clinical use. The dosage of some patients should be adjusted to achieve satisfactory therapeutic effect. Pharmacokinetic parameters of metformin are affected by many factors ，including respects of transporter gene polymorphism ，drug interaction ，intestinal flora ，plateau hypoxia and physiological function and so on. In order to guide the clinical individualized use of metformin ，this study reviews the research progress on the influencing factors of metformin pharmacokinetics.

Tibetan is a kind of medicine which extensively absorbed and fused the Chinese Traditional Medicine, Indian medicine and food through long-term practice and form the unique medical system. At the same time, the Qinghai Tibet plateau has characteristics of high altitude and lack of resources and oxygen, which has formed its unique geographical environment and grow a lot of rare medicinal plants. Tibetan medicine has a long history and is one of the relatively complete and influential ethnic medicines in China, which has played an important role in the treatment of plateau diseases. In recent years, with the increasing of economic activities in the plateau, the plateau anoxia had greatly affected the working capacity of the plateau. According to "Chinese medicine" through the literature, the pharmacological activities, active ingredients, growing environment of Tibetan medicine with good plateau hypoxia effect were reviewed and according to the site, which could be divided into the lung protection medicine, the cardiac protection medicine, the brain protection medicine, the liver protection medicine, the improvement of fatigue medicine and other medicine, which could provide theoretical basis for finding more potential anti-hypoxia drugs.

Objective To establish a method for the determination of total polyphenols and catechins in betel nut polyphenols extract, and provide reference for the quality control of betel nut polyphenols extract. Methods The content of total phenol in betel nut extract was determined by ultraviolet spectrophotometry. The content of catechins was determined by HPLC. Results The linear range of total polyphenols in betel nuts extract was 9.8~58.8 μg/ml. The three components of catechin, epicatechin and protocatechuic acid were completely separated by HPLC, and the linear relationship was good in their respective ranges, with the recoveries between 99.17% and 101.67%, the RSD between 1.2% and 2.5%. Conclusion The established method is simple, stable and reliable, which could be used for the quantitative analysis of betel polyphenol extract, and provide experimental basis for the quality control of betel polyphenol extract.