[Improvement effect of vitamins B1, B2 and PP supplementation on substance metabolism of mice exposed to acute hypoxia].

OBJECTIVE: To explore the improvement effect of vitamins B1, B2, PP supplementation to the metabolism changes of carbohydrates, lipids, protein and energy in mice exposed to acute hypoxia. METHODS: Fifty male Kunming mice were randomly divided into normal, acute hypoxia, acute hypoxia plus 2 times, 4 times and 8 times vitamins B1, B2, PP supplemented groups. All mice were fed corresponding diets for two weeks and then except the normal group were exposed to a simulated altitude of 6 000 meters for 8 hours. The changes of glucose, pyruvate, lactate, urea nitrogen, free fatty acids and beta-hydroxybutyric acid from serum, liver glycogen and blood adenosine triphosphate (ATP) concentration were measured. RESULTS: After being exposed to acute hypoxia, the mice glucose, liver glycogen, pyruvate, lactate, free fatty acids, beta-hydroxybutyric acid and urea nitrogen level were increased significantly (P < 0.05), while blood ATP concentration was decreased. In the vitamins B1, B2 and PP supplemented groups, these changes were improved. CONCLUSION: The significant changes in carbohydrate, lipid and protein metabolism were observed in mice exposed to acute hypoxia, and the supplementation of vitamins B1, B2 and PP was proved to be beneficial in improving some metabolic pathways. It is suggested that the supplemented dose of four times was good.

Metabolomic study on vitamins B1, B2, and PP supplementation to improve serum metabolic profiles in mice under acute hypoxia based on ¹H NMR analysis.

OBJECTIVE: To explore metabolic changes after acute hypoxia and modulating effect of vitamins B1, B2, and PP supplementation in mice exposed to acute hypoxia. METHODS: Fifty male Kunming mice were randomly divided into 5 groups: normal, acute hypoxia, acute hypoxia with 2, 4 and 8 time-vitamins B1, B2, and PP supplementation. All mice were fed with corresponding diets for two weeks and then were exposed to a simulated altitude of 6,000 meters for 8 h, except for the normal group. Nuclear magnetic resonance analysis was used to identify the changes of serum metabolic profiles. RESULTS: There were significant changes in some serum metabolites under induced acute hypoxia, essentially relative increase in the concentrations of lactate, sugar and lipids and decrease in ethanol. The serum levels of choline, succinate, taurine, alanine, and glutamine also increased and phosphocholine decreased in the acute hypoxia group. After vitamins B1, B2, and PP supplementation, all these metabolic changes gradually recovered. CONCLUSIONS: Significant changes in serum metabolic profile were observed by metabolomics in mice exposed to acute hypoxia, and vitamins B1, B2, and PP supplementation proved to be beneficial to improving some metabolic pathways. It is suggested that the dietary intakes of vitamins B1, B2, and PP should be increased under hypoxia condition.

[Intervention of nutritional status and hypoxia endurance by a nutritional supplement in young adults living at high altitude].

AIM: To investigate the effects of a nutritional supplement on nutritional status and hypoxia endurance in young adults living at high altitude. METHODS: 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. RESULTS: 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. CONCLUSION: The nutritional supplement can improve nutritional status and increase the hypoxia endurance in young adults living at high altitude.

[The regulatory effects of arginine on hepatic insulin-like growth factor-1 secretion in rats and its implication].

OBJECTIVE: To explore the regulatory effect of arginine on the secretion of hepatic insulin-like growth factor-1 (IGF-I), and the mechanism of enhancing the immune function by arginine. METHODS: Wistar rats were randomly divided into normal control (NC), wound control (WC), and wound with arginine (Arg) groups, with 8 rats in each group. The rats in WC and Arg groups were inflicted with soft tissue trauma on the back. The rats in Arg group were fed a diet supplemented with 5% arginine for one week, while those in NC and WC groups were fed with glycine. The serum contents of arginine, ornithine, growth factor (GH), NO and IGF-I were determined 7 days after feeding. T cell proliferation and IGF-I mRNA expression in hepatic tissue were also measured. Meanwhile, the rat hepatocytes were cultured in serum-free medium containing different concentrations of arginine. The supernatant was collected for the determination of IGF-I level. RESULTS: 1). There was no obvious difference of the serum level of arginine and ornithine between NC and WC groups (P > 0.05), but the contents of them were obviously higher in the Arg group compared with other two groups (P < 0.01). 2). No difference in the serum GH level was found among all the groups (P > 0.05), but the serum NO content in WC and Arg groups was significantly lower than that in NC group (P < 0.01), and the serum IGF-I content in WC group decreased obviously compared with that in NC group (P < 0.01). 3). The thymocyte proliferation rate in WC group was also markedly lower than that in NC group (P < 0.01), but that in Arg group was improved compared with WC group (P < 0.01). 4). The expression of hepatic IGF-I mRNA: The relative value of IGF-I mRNA was 1.19 +/- 0.06, 1.08 +/- 0.06 and 1.29 +/- 0.06 in NC, WC and Arg, respectively, while the value in WC was lower than that in NC (P < 0.05) group, and that in Arg group was much higher than that in WC group (P < 0.01). 5). The IGF-I level in the supernatant of cultured hepatocytes: When Arg concentration was 0.0750, 0.7500, 7.5000 mmol/L in the culture medium, the IGF-I level in the supernatant of hepatic cell medi-um was obviously higher than that in the medium without arginine (P < 0.01). Although IGF-I level decreased in the culture medium with arginine in the dose of 37.5000 mmol/L, it was still obviously higher than that in the medium without arginine (P < 0.01). CONCLUSION: Arginine could also produce the immune enhancing effect by stimulating hepatic IGF-I secretion.