Simultaneous oral and inhalational intake of molecular hydrogen additively suppresses signaling pathways in rodents.

Molecular hydrogen (H2) is an agent with potential applications in oxidative stress-related and/or inflammatory disorders. H2 is usually administered by inhaling H2-containing air (HCA) or by oral intake of H2-rich water (HRW). Despite mounting evidence, the molecular mechanism underlying the therapeutic effects and the optimal method of H2 administration remain unclear. Here, we investigated whether H2 affects signaling pathways and gene expression in a dosage- or dose regimen-dependent manner. We first examined the H2 concentrations in blood and organs after its administration and found that oral intake of HRW rapidly but transiently increased H2 concentrations in the liver and atrial blood, while H2 concentrations in arterial blood and the kidney were one-tenth of those in the liver and atrial blood. In contrast, inhalation of HCA increased H2 equally in both atrial and arterial blood. We next examined whether H2 alters gene expression in normal mouse livers using DNA microarray analysis after administration of HCA and HRW. Ingenuity Pathway Analysis revealed that H2 suppressed the expression of nuclear factor-kappa B (NF-κB)-regulated genes. Western blot analysis showed that H2 attenuated ERK, p38 MAPK, and NF-κB signaling in mouse livers. Finally, we evaluated whether the changes in gene expression were influenced by the route of H2 administration and found that the combination of both HRW and HCA had the most potent effects on signaling pathways and gene expression in systemic organs, suggesting that H2 may act not only through a dose-dependent mechanism but also through a complex molecular network.

Acetone concentration in gas emanating from tails of diabetic rats.

This study investigated the effects of diabetic rats induced by streptozotocin (STZ) on acetone concentration emanating from the tail of a rat. Experiments were carried out with male Wistar rats (9 weeks of age, 220 - 250 g body weight). Glucose concentration in the blood was 10.8 ± 0.7 mmol/l for the control group and 39.6 ± 2.4 mmol/l for the diabetic group. ß-Hydroxybutyrate concentration in blood was 218 ± 52 µmol/l for the control group and 1439 ± 101 µmol/l for the diabetic group. Both glucose and ß-hydroxybutyrate concentrations in the blood of the diabetic group were significantly higher than those of the control group (p < 0.001). Skin gas acetone concentration emanated from rat tail was 124 ± 46 ppb for control and 1134 ± 417 ppb for diabetic. Skin gas acetone concentration emitted from the tail of a rat with diabetes was significantly higher than that from a rat in the control group (p < 0.001). The result indicates that skin acetone emanating from a rat tail is a useful parameter to use for insulin-dependent diabetes (type I).

Drinking hydrogen water and intermittent hydrogen gas exposure, but not lactulose or continuous hydrogen gas exposure, prevent 6-hydorxydopamine-induced Parkinson's disease in rats.

BACKGROUND: Lactulose is a synthetic disaccharide that can be catalyzed only by intestinal bacteria in humans and rodents, and a large amount of hydrogen is produced by bacterial catalysis of lactulose. We previously reported marked effects of ad libitum administration of hydrogen water on prevention of a rat model of Parkinson's disease (PD). METHODS: End-alveolar breath hydrogen concentrations were measured in 28 healthy subjects and 37 PD patients, as well as in 9 rats after taking hydrogen water or lactulose. Six-hydroxydopamine (6-OHDA)-induced hemi-PD model was stereotactically generated in rats. We compared effects of hydrogen water and lactulose on prevention of PD. We also analyzed effects of continuous and intermittent administration of 2% hydrogen gas. RESULTS: Hydrogen water increased breath hydrogen concentrations from 8.6 ± 2.1 to 32.6 ± 3.3 ppm (mean and SEM, n = 8) in 10 min in healthy subjects. Lactulose increased breath hydrogen concentrations in 86% of healthy subjects and 59% of PD patients. Compared to monophasic hydrogen increases in 71% of healthy subjects, 32% and 41% of PD patients showed biphasic and no increases, respectively. Lactulose also increased breath hydrogen levels monophasically in 9 rats. Lactulose, however, marginally ameliorated 6-OHDA-induced PD in rats. Continuous administration of 2% hydrogen gas similarly had marginal effects. On the other hand, intermittent administration of 2% hydrogen gas prevented PD in 4 of 6 rats. CONCLUSIONS: Lack of dose responses of hydrogen and the presence of favorable effects with hydrogen water and intermittent hydrogen gas suggest that signal modulating activities of hydrogen are likely to be instrumental in exerting a protective effect against PD.

Influence of cycle exercise on acetone in expired air and skin gas.

This study investigated the influence of cycle exercise on acetone concentration in expired air and skin gas. The subjects for this experiment were eight healthy males. Subjects performed a continuous graded exercise test on a cycle ergometer. The workloads were 360 (1.0 kg), 720 (2.0 kg), 990 (2.75 kg) kgm/min, and each stage was 5 min in duration. A pedaling frequency of 60 rpm was maintained. Acetone concentration was analyzed by gas chromatography. The acetone concentration in expired air and skin gas during exercise at 990 kgm/min intensity was significantly increased compared with the basal level. The skin-gas acetone concentration at 990 kgm/min significantly increased compared with the 360 kgm/min (P < 0.05). The acetone excretion of expired air at 720 kgm/min and 990 kgm/min significantly increased compared with the basal level (P < 0.05). Acetone concentration in expired air was 4-fold greater than skin gas at rest and 3-fold greater during exercise (P < 0.01). Skin gas acetone concentration significantly related with expired air (r = 0.752; P < 0.01). This study confirmed that the skin-gas acetone concentration reflected that of expired air.

The Relationship between Exercise Intensity and Lactate Concentration on the Skin Surface.

We examined the relationship between skin surface lactate concentration on working muscle and heart rate during continuous graded cycling exercise. Sixteen healthy male volunteers participated in this study. A plastic container with 100 µl 1% ethanol was put on the skin surface on the belly of rectus femoris muscle. The workloads were 300, 600, 900 and 1080 (or 990) kpm/min, and each stage was 5 min in duration. Sample collections were performed at rest, during exercise, and recovery. The lactate concentration during exercise significantly increased compared to the basal level (p<0.05 or p<0.001). Skin surface lactate concentration was found to correlate significantly with heart rate at the exercise intensity of 360 kpm/min (r=-0.52, p<0.05), 720 kpm/min (r=-0.74, p<0.01) and 900 kpm (r=-0.53, p<0.05). This study confirmed that 1) the increase in lactate concentration on the skin surface on working muscle is associated with increase in exercise intensity (heart rate), and 2) the skin surface lactate concentration on the working muscle can be used as a parameter of exercise intensity in each subject.