The Effects Of Acute Hypoxia On Triglyceride Metabolism In Rats

Objective: To investigate the effects and mechanisms of high altitude hypoxia on the triglyceride catabolism of rats.Methods: 30 male SD rats were randomly divided into normal control group,the group of hypoxia for 3 days,and each group of 15 rats.The rats of hypoxia groups were fed in a hypobaric chamber simulated 5 000 meters high altitude hypoxia environment,and the rats of the normal control group were fed in the animal room of School of Medicine,North West Agricultural and Forestry University(The elevation is 400 meters).Body weight,blood lipid(Triglyceride concentration),hemoglobin concentration and the concentration of leptin and insulin were detected at two time points,namely before the experiment and on the third day.The Expression levels of m RNA of Lipoprotein lipase(LPL)and hormone sensitive triglyceride lipase(HSL)were detected by RT-PCR,while the expression level of hypoxia-inducible factor(HIF-1?)and angiopoietin like protein 4(Angptl4)and Peroxisome Proliferator Activated Receptor(PPAR?)were detected by Western blot.Results: 1.Compared with normoxia control group,the weight changes of hypoxia group showed statistically significant(P<0.05),the weight was decreased,suggesting that stimulation of acute hypoxia can make body weight loss;2.Compared with the normoxia control group,the changes of hemoglobin concentration and triglyceride concentration in hypoxia group were statistically significant,and the concentration of hemoglobin and triglyceride in hypoxic group were higher than that of normoxic group(P<0.05),suggesting that stimulation of acute hypoxia can make hemoglobin concentration and triglyceride concentration increase;What's more,the concentration of leptin and insulin in hypoxic group were higher than that of the normoxic group(P<0.05),suggesting that stimulation of acute hypoxia can make the concentration of leptin and insulin increase;3.Compared with normoxia control group,the hypoxia group showed significantly decreased the expressions of LPL m RNA(P<0.05),suggesting hypoxia inhibits the expression of LPL m RNA in hepatocytes;4.The expression level of HSL m RNA in hypoxia group was significantly higher than that of normoxia control group,the difference was clearly significant(P<0.05),suggesting that acute hypoxia induced the expression of HSL m RNA in liver cells(P<0.05);5.There are no significant diferences between the hypoxia group and the normoxia control group,suggesting that acute hypoxia can't obviously change the expression of Angptl4 protein in hepatocytes.However,the expression of HIF-1? and PPAR? protein in H3 group clearly higher than that of normoxic group(P<0.05),suggesting that stimulation of acute hypoxia can help the expression of PPAR? and HIF-1? protein increase in hepatocytes.Conclusion: High altitude hypoxia is able to increase triglyceride decomposition.These effects may be derive from down-regulation of LPL m RNA,but promoting the expression of HSL m RNA,HIF-1?,PPAR?,leptin and insulin.