Inhibition of Fe-induced colon oxidative stress by lactobacilli in
mice
Jin Sun, Xiao-Li Hu, Guo-Wei Le and Yong-Hui Shi
World Journal of Microbiology and Biotechnology 2012
Abstract
Iron (Fe) can promote hydrogen peroxide (H2O2) and hydroxyl radical
generation in the colonic surface and promote growth of Fe-dependent
bacteria.
Some Lactobacillus strains are resistant to oxygen free-radicals,
allowing them to survive in a Fe-modulated mucosal environment and
influence colon microbial ecology and redox state.
Here, we investigated the capacity of lactobacilli with different
antioxidant abilities to modify the bacterial profile and prevent
oxidative stress in the colon of Fe-overloaded mice.
Survival time of Lactobacillus rhamnosus LGG (LGG) in the presence of
H2O2 and hydroxyl radical was significantly longer compared with the
mid- and non-antioxidative strains, Lactobacillus paracasei Fn032 and
Lactobacillus plantarum Fn001, respectively.
Different Lactobacillus strains are specific in free-radical
scavenging activities of their cell-free extracts, which increased to
varying extent depending on strains when bacteria were exposed to
simulated gastric and pancreatic juice.
Fe-overloaded mice showed increased colonic luminal ferrous Fe
content, Enterococcus and Escherichia coli concentrations, mucosal
malondialdehyde and free-radicals, and decreased mucosal total
antioxidative capacity and oxidative enzymatic activity.
Translocation of endotoxin to the liver was also significantly
increased (P < 0.05).
Lactobacilli inhibited ferrous Fe accumulation, especially in LGG and
Fn032. LGG significantly inhibited the increase of colonic mucosal
free-radicals and malondialdehyde content (P < 0.05).
Fn032 only inhibited malondialdehyde (P < 0.05). LGG and Fn032
significantly inhibited increases in colonic Enterococcus (P < 0.05).
Fn001 showed no significant antioxidative ability in vivo.
The difference of these effects in vivo were well agreed with
scavenging activities against reactive oxygen species (ROS) of
simulated gastrointestinals fluid pretreated cells in vitro.
In conclusion, ROS scavenging activities was essential for
Lactobacillus to prevent oxidative stress in vivo and inhibition of
ROS-producing bacterial growth and mucosal barrier injury.
Keywords Lactobacillus – Antioxidant – Iron overload diet – Colon
DOI: 10.1007/s11274-012-1172-5Online First™
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