Intervention of nutritional status and hypoxia endurance by a nutritional supplement in young adults living at high altitude / 中国应用生理学杂志

<p><b>AIM</b>To investigate the effects of a nutritional supplement on nutritional status and hypoxia endurance in young adults living at high altitude.</p><p><b>METHODS</b>Forty healthy male young adults were recruited and randomly assigned to control and intervention groups. The nutrition survey was carried out using weighing method. The intervention group was given a nutritional supplement specifically designed for use at high altitude, while the control group was treated with a supplement made of stir-fried flour. After 20 days of supplementation, they marched from the altitude of 3700 m to 5100 m. The changes in HR, SaO2, serum concentrations of VA and VB2 and some minerals were measured.</p><p><b>RESULTS</b>The results of nutrition survey showed that the ratio of three macronutrients was not adequate and the intakes of calcium, VA and VB2 were below Chinese RNI. The serum concentrations of calcium, magnesium and VA were below normal references. The serum VB2 concentration was at the low level o f normal reference. The nutritional supplement could increase the serum concentrations of calcium, magnesium, VA and VB2, indicating an improved nutritional status. The changes in HR and SaO2 were diminished in intervention group compared with control group.</p><p><b>CONCLUSION</b>The nutritional supplement can improve nutritional status and increase the hypoxia endurance in young adults living at high altitude.</p>

Effects of hypoxia on the secretions of proinflammatory cytokines TNF-alpha and IL-6 in macrophages and its mechanism / 中国应用生理学杂志

<p><b>AIM</b>To investigate the effects of hypoxia on the secretions of proinflammatory cytokines TNF-alpha and IL-6 and to inquire into the mechanism.</p><p><b>METHODS</b>Separated mice abdominal macrophages which were identified with non-specific esterase dye method, and created the hypoxic cultured model. The levels of TNF-alpha and IL-6 in the medium were determined by ELISA method. The mRNA expressions of TNF-alpha and IL-6 were measured by RT-PCR method. NF-kappaB activation was assayed by Western blot method. Finaly, we added cortone (5 microg/ml) to the medium, then observed the secretion levels of TNF-alpha and IL-6 during hypoxia.</p><p><b>RESULTS</b>The secretions of TNF-alpha and IL-6 from Mphi exposed to hypoxia for 12 h were increased significantly compared with control (P < 0.01). The expressions of TNF-alpha mRNA and IL-6 mRNA were enhanced obviously contrasted with control (P < 0.01). NF-kappaB activation in Mphi nuclei was raised at 2 h during hypoxia and persisted to 5 h. We added cortone to the medium and found no significant change in secretion of TNF-alpha and IL-6 during hypoxia.</p><p><b>CONCLUSION</b>Hypoxia could activate NF-kappaB and make it shift to nucleus which promoted the transcriptions and expressions of TNF-alpha and IL-6.</p>

Nuclear factor kappa B signal transduction in macrophages during hypoxia: reactive oxygen species generation / 生理学报

The effects of hypoxia on the level of reactive oxygen species (ROS), IkappaBalpha tyrosine phosphorylation, transcription of P65 mRNA and NF-kappaB activation in isolated rat peritoneal macrophages were investigated by DCFH-DA fluorescence spectrophotometry, Western blotting and RT-PCR. The results obtained are as follows. (1) During hypoxia, the levels of intracellular ROS began to increase at 1 h, then reached a peak at 2 h, and began to decrease after 3 h. IkappaBalpha tyrosine phosphorylation began to rise after 2 h hypoxia and was the highest after 3 h hypoxia. After 4 h hypoxia it decreased gradually. NF-kappaB activation began to increase after 3 h hypoxia, and reached a peak after 4 h hypoxia. (2) When antioxidant NAC (500 mmol/L) was added into the medium, the level of IkappaBalpha phosphorylation showed no significant changes during hypoxia. After adding protein tyrosine kinase inhibitor genistein (200 micromol/L), NF-kappaB activation induced by hypoxia was blocked significantly. (3) The expression of p65 mRNA was also elevated markedly during hypoxia. These results suggest that hypoxia may lead to IkappaBalpha phosphorylation and NF-kappaB activation through intracellular ROS, and that the regulation of NF-kappaB activity may involve IkappaBalpha phosphorylation and the expressions of each subunit gene of NF-kappaB.