Plasma and Liver Lipid Profiles in Rats Exposed to Chronic Hypobaric Hypoxia: Changes in Metabolic Pathways

Abstract

Lipid metabolism under chronic hypoxia (CH) has not received equal attention as intermittent hypoxia (IH). To determine the CH-induced changes in plasma and liver, as well as the mRNA and protein expression of two key enzymes in the triglyceride and cholesterol biosynthesis pathways, SREBP-1 (HMG-CoA reductase) and SREBP-2 (SCD-1), we exposed adult male Wistar rats to CH (4600 m; n=15) for 30 days compared to normoxic rats (n=15). The CH rats exhibited weight loss (p<0.001), higher hematocrit (%), and higher hemoglobin (g/dL) (p<0.01). In the plasma of CH rats, total cholesterol and LDL-cholesterol increased at day 15. VLDL-cholesterol and triglycerides (p<0.01) greatly increased (35%), while HDL-cholesterol decreased (p<0.01). Triglycerides and VLDL-cholesterol remained elevated by 28% at day 30 (p<0.01). Hepatic triglycerides increased two-fold, while total cholesterol increased by 51% (p<0.001; p<0.05). Upregulation of SCD-1 mRNA and protein was observed in the CH rats (p<0.01); however, no differences were observed in HMG-CoA reductase mRNA or protein expression in both groups. In conclusion, CH, like IH, alters lipid profiles by increasing triglycerides in the plasma and liver and upregulating triglyceride biosynthesis without affecting the cholesterol biosynthetic pathway. Additional involved mechanisms require further study because of the importance of lipids in cardiovascular risk.

Resveratrol ameliorates chronic high altitude exposure‐induced oxidative stress and suppresses lipid metabolism alteration in rats

“…In this study, we investigated the role and mechanism of resveratrol in lipid metabolism in rats when exposed to high altitude hypoxia environment for 30 days. Marked body weight loss was observed after high altitude hypoxia exposure, which was consistent with previous studies [3,21,22]. Moreover, less food intake was observed in our current and previous experiments.…”

Ω3 Supplementation and Intermittent Hypobaric Hypoxia Induce Cardioprotection Enhancing Antioxidant Mechanisms in Adult Rats

“…This effect could be explained by the higher metabolic and ventilatory demands as a consequence of the reduced environmental oxygen [ 2 , 83 ]. Indeed, metabolic effects of chronic IHH are associated with an improved in glucose tolerance and significantly increased VLDL-cholesterol, which can affect long-term cardiovascular function and mortality [ 84 , 85 ]. The present findings imply that chronic IHH could be useful in the clinical setting for the prevention of IR injury in ischemic diseases.…”

Effects of Ketoprofen in Spermatogenesis of Mice Exposed to Continuos Hypobaric Hypoxia

“…This increase in hematocrit which reflects the physiological response is triggered against the decrease in concentration of oxygen available in hypoxia. The body responds to this condition compared accelerating erythrocyte production by increasing the delivery of oxygen to tissues, offsetting the decline in circulating oxygen (Siques et al, 2014). Ketoprofen administration did not modify this response, with similar percentages of animals without administration of ketoprofen (de Souza Silva et al, 2006).…”