Objective To investigate the effect of hypoxia with cold on the heart and brain damage in rats by simulating 6 000 m high altitude at different exposure time,established a rat model of acute mountain sickness for the related mechanism studies.Methods 32 healthy male Wistar rats were randomly divided into normal control group,hypoxia with cold 1 d,3 d and 5 d group,8 rats in each group.The normal control group was kept in the plain environment(1 500 m)without any treat-ment.The other three groups were placed in large hypobaric hypoxia chamber to simulate 6 000 m altitude with different ex-posed times.HE staining was used to observe the pathological changes of heart and brain tissue.The changes of biochemical indexes were measured to evaluate the damage of heart and brain tissue at different hypoxia times.Results HE staining showed that hypoxia with cold induced rat heart and brain damage with different degrees.The myocardial tissue damage was in-creased with exposure time.The most serious brain damage happened in day 3.Compared with the normal control group,the content of MDA and LD in the myocardial tissue of hypoxia rats were significantly increased(P<0.05 or P<0.01)with pro-longed time,while the contents of GSH,T-SOD and the activity of Na+K+-ATPase were reduced(P<0.05 or P<0.01). The content of MDA in brain tissue was significantly increased at day 1 and day 3(P<0.05 or P<0.01).LD content was sig-nificantly increased(P<0.05)with time.The content of GSH,the activity of T-SOD and Na+K+-ATPase were significantly reduced in day 3(P<0.05).Conclusion Simulating an altitude of 6 000 m caused obvious damage on the heart and brain tis-sues of rats.The degree of damage was related to the exposure time to hypoxia with cold.The decrease of body′s antioxidant capacity,the increase of free radicals and energy metabolism disorders are important factors leading to heart and brain injury.

Objective To investigate the anti-hypoxia effects of octacosane and the petroleum ether extract from Saus-surea Involucrate(PESI)on the water,sugar,lipid and protein metabolism of mice at simulated high altitude.Methods The healthy adult male BALB/C mice were randomly divided into normal control group,hypoxic model group,acetazolamide group, the petroleum ether of Saussurea involucrata group and octacosane group.Drugs were administered i.v 20 mins before the mice were exposed to a simulated high altitude of 6 000 m for 8 hours in an animal decompression chamber.The mice were sacrificed at the end of 8 hours.Organ water content,organ indexes and metabolism indicators of sugar,protein and lipid were deter-mined.Results The edema of heart,brain and lung was reduced notably(P<0.05,P<0.01)in the mice received PESI at 200 mg/kg and octacosane at 100 mg/kg.In the treated groups,the increase of blood sugar,muscle glycogen,TG(triglycer-ide),TC(total cholesterol)were all significantly inhibited,the decrease of liver glycogen,the protein content of heart and brain was also remarkably blocked(P<0.05,P<0.01).Conclusion PESI and octacosane effectively regulate the metabolism of hypoxic mice and reserve the body′s energy for survival by lowering the basic metabolism.

Objective To study pharmacodynamics of the effective anti-hypoxia components in the petroleum ether ex-tract of Saussurea Involucrate(PESI)and octacosane.Methods PESI and octacosane were first evaluated by normobaric hy-poxia model,acute decompression model and followed by chemical induced hypoxic models with potassium cyanide,sodium ni-trite and isoprenaline hydrochloride poisoning.Results PESI and octacosane can effectively prolong the survival time of hypo-baric hypoxic mice(P<0.01)and reduce the mortality of acute hypobaric hypoxia mice(P<0.01)in a dose-dependent man-ner.Anti-hypoxic potency of PESI and octacosane obtained by chemical induced hypoxic model indicated that they significantly increase survival time(P<0.05)of hypoxia mice than acetazolamide.Conclusion PESI and octacosane have good anti-hypoxia activity.