Study Of Probiotics On Ameliorating Chronic Alcoholic Liver Injury

Alcoholic liver injury, which results from chronic alcohol abuse or recurrentacute binge drinking, remains one of the most harmful liver diseases in the world.However, the pathogenesis is quite complex. Up to now, there is no innocuous andenough effective therapy means in clinic. Probiotics have demonstrated severalbeneficial properties, including antioxidative properties, antitumor properties, theabilities to regulate intestinal flora and improve immunity, which makes probiotics thefocus of research. The present study aimed to exploit the potential roles of probioticsin the alcoholic liver injury from the view of oxidative stress. The probiotics werescreened with hepatoprotective function according to antioxidative activity, and thentheir beneficial effects were evaluated in vivo, and their application value in practicalproduction was finally considered.Fifty-five Lactobacillus strains were investigated for their abilities to scavengethe DPPH free radical and hydroxyl radical, to inhibit the lipid peroxidation and theirreducing activities. Two strains were selected based on the antioxidative activities invitro, Lactobacillus rhamnosus Z7(L. rhamnosus Z7) and Lactobacillus plantarumN31(L. plantarum N31), respectively. The two strains displayed as high antioxidativeability as the positive control Lactobacillus rhamnosus GG (LGG) and even muchbetter.In order to evaluate the hepatoprotective function of L. rhamnosus Z7and L.plantarum N31, a mouse model was induced by orally feeding alcohol by gavagewhen simultaneously treated with different probiotics and the commonly used drugHu-Gan-Pian (HGP). Biochemical analysis was performed for both serum and liverhomogenate. Detailed intestinal flora and histological analyses were also carried out.The results showed that the administration of probiotics (LGG, L. rhamnosus Z7and L.plantarum N31) could inhibit the increase in the serum levels of alanineaminotransferase, aspartate aminotransferase, γ-glutamyl transferase, and theconcentration of triglyceride, total cholesterol in both serum and liver, indicating that the probiotic strains could lower the fat and protect the liver. In contrast to the modelgroup, the probiotic groups reduced the content of malondialdehyde greatly andincreased the content of glutathione, glutathione peroxidase and total superoxidedismutase significantly, thereby enhancing the antioxidative abilities. Besides, theenteric dysbiosis and endotoxemia caused by alcohol was restored by increasing thenumbers of both lactobacilli and bifidobacteria and decreasing the numbers of bothenterococci and enterobacter. Histological analysis also confirmed the protectiveeffect of the probiotics. In contrast to the other lactobacilli and to the drugadministered in the study, L. rhamnosus Z7was shown to have almost the samebeneficial effects as LGG on alcoholic liver disease and to perform much better thanthe commercial drug HGP in some respects. In conclusion, the selected L. rhamnosusZ7and L. plantarum N31with higher antioxidative abilities might be beneficial forthe prevention and improvement of alcohol-induced hepatic steatosis and damage byreducing oxidative stress and restoring the intestinal flora.In the study of the application of the two probiotics in the dairy products, L.rhamnosus Z7and L. plantarum N31could not curd in the skimmed milk and thereason may lie in that they could not utilize lactose. Both the two strains couldcoculture with the commercial starters in the glucose-supplemented skimmed milk.There were no significant differences between the complex fermented milk andcommercial starters fermented milk in viscosity, texture, bacterial count and sensoryproperties. Therefore, L. rhamnosus Z7and L. plantarum N31could be used aspotential probiotics with hepatoprotective application in the fermented milk and thedevelopment of new products.