Protective Effects Of Oxygen Enrichment Inhalation On Acute High Altitude Pulmonary Edema Of Rats

Objective:To estibalish the rats model of high-altitude pulmonary edema by putting Wistar rats in hypobaric chamber, the severity of pulmonary edema in different group was compared.Methods:Male Wistar rats were randomly divided into three groups:control group,24 h hypoxia group,48 h hypoxia group. Except for the control group,rats in the other groups were put in a hypobaric chamber for 24h and 48h to produce a rat model of high altitude pulmonary edema(HAPE).The wet to dry ratio(W/D),lung oxide synthase (NOS),lung endothelin-1(ET-1) and histological measurements were conducted on each animal.Results:Compared with the control group.The W/D ratio and the ET-1 were significant increased, the activity of NOS were lower significantly in the 24h hypoxia group and 48h hypoxia group(p<0.05).Pulmonary interstitial edema haemorrhage were found in the 24h and 48h hypoxia group.Comparied with the 24h hypoxia group,the wet to dry ratio and the endothelin were significantly increased,the activity of NOS were significantly lower of the 48h hypoxia group(p<0.05).Conclusion:The model of high altitude pulmonary interstitial edema were successful set up by putting the Wistar rats in hypobaric chamber for 24 h and 48 h,the severity of pulmonary edema in the 48h hypoxia group was worse than the 24h hypoxia group.Part 2:The protective effects of oxygen enrichment inhalation on the acute Objective:To investigate the protective effects of oxygen enrichment inhalation on preventing acute high altitude pulmonary edema(HAPE) of rats and compare the effects of various oxygen enrichment inhalation.Methods:Fourty four male Wistar rats were randomly and averagely divided into control,hypoxia,fulltime oxygen enrichment,noctural oxygen enrichment groups.Rats with various inhalations were exposed to simulated 6000m for 48h except control group. After intervention of oxygen enrichment inhalation,the wet to dry ratio(W/D),bronchoalveolar lavage fluid (BALF) and the histological measurements were measured.The nitric oxide (NO) content and nitric oxide synthase (NOS) in serum and lung homogenate of rats were detected.Results:Comparing with the control group,hypoxia group showed significant increased W/D ratio and BALF protein concentration and decreased level of NO and activity of NOS (p<0.05).Interstitial pulmonary edema,haemorrhage and neutrophil infiltration were found in the hypoxia group.the W/D ratio and BALF protein concentration in both oxygen enrichment group and nocturnal oxygen enrichment group were decreased compaired with that in hypoxia group(p<0.05),while the levels of NO and the activity of NOS were increased (p<0.05).Conclusion:Oxygen enrichment inhalation have the protective effects on HAPE by promoting the activity of NOS and the release of the NO,there is no difference between the oxygen enrichment and noctural oxygen enrichment.