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. 2016 Feb 8:6:20379.
doi: 10.1038/srep20379.

Colonic Fermentation Promotes Decompression sickness in Rats

Sébastien de Maistre  1 , Nicolas Vallée  2 , Emmanuel Gempp  1 , Kate Lambrechts  2 , Pierre Louge  1 , Claude Duchamp  3 , Jean-Eric Blatteau  2
Affiliations

Colonic Fermentation Promotes Decompression sickness in Rats

Sébastien de Maistre et al. Sci Rep. .

Abstract

Massive bubble formation after diving can lead to decompression sickness (DCS). During dives with hydrogen as a diluent for oxygen, decreasing the body's H2 burden by inoculating hydrogen-metabolizing microbes into the gut reduces the risk of DCS. So we set out to investigate if colonic fermentation leading to endogenous hydrogen production promotes DCS in fasting rats. Four hours before an experimental dive, 93 fasting rats were force-fed, half of them with mannitol and the other half with water. Exhaled hydrogen was measured before and after force-feeding. Following the hyperbaric exposure, we looked for signs of DCS. A higher incidence of DCS was found in rats force-fed with mannitol than in those force-fed with water (80%, [95%CI 56, 94] versus 40%, [95%CI 19, 64], p < 0.01). In rats force-fed with mannitol, metronidazole pretreatment reduced the incidence of DCS (33%, [95%CI 15, 57], p = 0.005) at the same time as it inhibited colonic fermentation (14 ± 35 ppm versus 118 ± 90 ppm, p = 0.0001). Pre-diveingestion of mannitol increased the incidence of DCS in fasting rats when colonic fermentation peaked during the decompression phase. More generally, colonic fermentation in rats on a normal diet could promote DCS through endogenous hydrogen production.

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Figures

Figure 1
Figure 1. Hydrogen in exhaled air just before and 3 hours after force-feeding in rats.
*denotes p < 0.05 between the groups.
Figure 2
Figure 2. Percents of symptomatic rats suffering from decompression sickness (DCS) within 30 min after surfacing.
*denotes p < 0.05 between the groups.
Figure 3
Figure 3. Percents of platelets consumption after decompression from the baseline.
*denotes p < 0.05 between the groups.
Figure 4
Figure 4. Distribution of rats in experimental groups and subgroups (MTZ: metronidazole, MNL: mannitol, EXP: exposed to pressurization).
Figure 5
Figure 5. Distribution of rats in experimental groups and subgroups (MTZ: metronidazole, MNL: mannitol, EXP: exposed to pressurization).
See this image and copyright information in PMC

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