Protective Effect Of Se-enriched Photosynthetic Bacteria On CCl₄ Induced Liver Injury In Mice

Selenium is an essential trace elemental for cell activity, and plays an important role on human immune system, antioxidant defense system and anticancer. In order to observe the protective effects of Se-enriched photosynthetic bacteria on acute liver injury, firstly the study optimized the experimental conditions for the reduction of selenite by photosynthetic bacteria. Several factors were investigated using single factor experiment design and L9(34) orthogonal design respectively, which included sodium selenite concentration (1mmol/L、2mmol/L、3mmol/L), bacteria inoculation amount (5%、 10%、15%), initial pH (5、6、7) and culture time (6d、7d、8d). In order to further study the biological activity of the red elemental selenium, in the study, mice were randomly divided in 9 groups:normal group, high dose Se control group(200μg/kg.BW), CCl4 liver injury model group, three groups of Se(50、100、200μg/kg.BW)and three corresponding groups of bacteria(50、100、200μg/kg.BW) to investigate the protective effective of the photosynthetic bacteria. Each group accepted their dose for consecutive 14 days. At the fifth day, every group except normal group and high dose Se control group, received 1% CCl4 (lOmL/Kg.BW).24 hours later, kit to detect the the activity of mouse serum alanin aminotransferase (ALT), aspartate aminotransferase(AST), alkaline phosphatase(AKP) and lactate dehydrogenase(LDH); and liver index, spleen index; liver antioxidant indicators:superoxide dismutase(SOD), hydrogen peroxide enzyme(CAT), glutathione peroxidase(GPx) and malondialdehyde (MDA), furthermore the liver were made into histopathological examination. The results show that:Firstly, the four factors have their impacts on the selenite reduction in the following order:sodium selenite concentration> culture time> the initial pH value> bacteria inoculation amount. The optimal selenite reduction conditions of strain N:sodium selenite concentration at 2.0 m mol/L, the initial pH value at 7.0, culture time for 8 days and 15% of bacteria inoculation amount, under which the selentie reduction rate reached 91.36%.Secondly, all indicators show that compared with the normal group, the model group was rebuilt and high dose Se control group keep the same level as the normal group. Compared with the model group, while the three bacteria groups keep the same level to the model group, the three dose of Se groups could reduce the content of serum enzyme ALT, AST, AKP, LDH; and reduce the liver index, spleen index; also increase the liver enzymes SOD, CAT, GPx, and reduce the MDA content.Thirdly, the dissection observation suggested that the Se-enriched photosynthetic bacteria could reduce the bleeding spots on the liver surface, and the HE section showed that the model group liver cell cord disordered, inflammatory cell infiltration, patches necrosis, cell swollen, the three Se groups could remit the symptom, the protective effect was better with higher dose.Conclusions: First, the Se-enriched photosynthetic bacteria could reduce the release of the serum enzymes and enhance the liver antioxidant enzymes, reduce the lipid peroxidation level. Second, also, the Se-enriched photosynthetic bacteria could protect the liver formation. Third, all results showed that the Se-enriched photosynthetic bacteria could protect the liver form CCl4 induced liver injury. The mechanism was thought to be its ability of eliminating free radical and inhibit lipid peroxidation.