Protective effects of lactic acid bacteria-fermented soymilk against chronic cadmium toxicity in mice

Abstract

Our previous study confirmed that Lactobacillus plantarum CCFM8610 has protective effects against chronic cadmium (Cd) toxicity in mice, whereas L. bulgaricus CCFM8004 fails to provide similar protection. This study was designed to evaluate the protective effects of soymilk fermented with these lactic acid bacteria, against chronic Cd toxicity in mice, and to give an insight into the mechanism of the conjunct effect of soymilk and these strains. Experimental mice were divided into five groups as control, Cd only, non-fermented soymilk plus Cd, CCFM8610-fermented soymilk plus Cd, and CCFM8004-fermented soymilk plus Cd. The treatment of all groups was carried out for 8 weeks. Levels of Cd were measured in feces and tissues, and alterations in several biomarkers of Cd toxicity were noted. The results showed that non-fermented soymilk gave limited protection against chronic Cd toxicity in mice. However, oral administration of L. plantarum CCFM8610-fermented soymilk was able to increase fecal Cd excretion, reduce tissue Cd burden, alleviate tissue oxidative stress, reverse changes in hepatic and renal damage biomarkers, and ameliorate tissue histopathological changes in mice, indicating that L. plantarum CCFM8610-fermented soymilk could be considered as a dietary therapeutic strategy against chronic Cd toxicity. The treatment of L. bulgaricus CCFM8004-fermented soymilk provided similar protection, although the effects were less significant than for CCFM8610 treatment. The conjunct effects of the strains and the soymilk may be attributed to the increased Cd excretion ability and antioxidative capacity after fermentation.