| Objective To study the effects of Lactobacillus casei on antioxidant,protecting the intestinal mucosa and regulating intestinal flora in aging mice;And explore the relationship between Lactobacillus casei and aging.Method 1.Animal model establishing and grouping: Kunming male mice,SPF level,weight(20±2)g,were randomly divided in to two groups: Control group(15 mice)and model group(60 mice).The mice in model group were administered with D-galactose through neck back hypodermic injection by injection dose of 400 mg/kg/d while the mice in the control group were administered with saline in the same method for 6 weeks.Cut tail to take blood and test the content of MDA in erythrocytes.Then the mice in model group were randomly re-divided into four groups based on the level of MDA: model group(10 m L/kg/d distilled water by gavage),vitamin E group(80 mg/kg/d vitamin E by gavage),intervention groups 1,2(5,10 m L/kg/d Lactobacillus casei by gavage);The control group was given with 10 m L/kg/d distilled water by gavage.At the same time D-galactose injection was given the same as before.After 30 days,mice were sacrificed and blood,plasma,liver and small intestine were gathered for further study.Feces were harvested in the metabolic cages before mice were sacrificed.2.Anti-oxidation index detection: The DNA damage of lymphocyte was evaluated by comet assay.The content of MDA in red blood cells was detected with TBA method.Protein carbonyls in liver was detected with DNPH method.The contents of GSH-PX and GSH in liver were measured with DTNB method.3.Intestinal barrier function testing: The ultrastructural changes of small intestinal mucosa were observed by transmission electron microscopy.The contents of D-lactate,DAO,and FABP2 in serum were detected with ELISA method.4.Detection of intestinal flora: The contents of Bifidobacterium,Lactobacillus,Escherichia coli and Enterococcus in the mice feces of each group were detected by real-time quantitative PC R.Result 1.Compared with the control group,the DN A damage in the model group was significantly increased(P<0.05);Compared with the model group,the DNA damage in the intervention groups 1,2 and vitamin E group decreased significantly(P<0.05);Compared with vitamin E group,there was no significant difference in DN A damage in both intervention groups 1,2(P>0.05).2.Compared with the control group,the contents of MDA and protein carbonyls in the model group were significantly increased(P<0.05);Compared with the model group,MDA content and protein carbonyl content in the intervention groups 1,2 and vitamin E group decreased significantly(P<0.05);Compared with vitamin E group,the content of protein carbonyl in intervention groups 1,2 were decreased(P<0.05)but the MDA were not significantly different(P>0.05).3.Compared with the control group,the contents of GSH and GSH-PX in the model group were significantly decreased(P<0.05);Compared with the model group,the GSH content in intervention groups 1,2 was significantly increased,and the GSH-PX in the intervention group 2 was significantly higher(P<0.05);Compared with vitamin E group,the contents of GSH and GSH-PX in intervention groups 1,2 were not significantly different(P>0.05).4.Transmission electron microscopy showed that in the control group,the structure of small intestine was clear and complete,the villi were arranged neatly and tightly,and the cells were tightly connected.In the model group,the villi were disordered,some lodging was lost,the cell junctions were swollen and the number of desmosomes was decreased.After giving vitamin E and low and high dose Lactobacillus casei,the status of intestinal villi and cell connection were improved significantly compared with the model group.5.Compared with the control group,the contents of D-lactate,DAO and FABP2 in model group were significantly increased(P<0.05);Compared with the model group,the D-LA,DAO and FABP2 contents of the intervention groups 1,2 and vitamin E group were significantly decreased(P < 0.05);Compared with vitamin E group,there was no significant difference in D-LA,DAO and FABP2 in intervention groups 1,2(P>0.05).6.Compared with the control group,the contents of Bifidobacterium,Lactobacillus and Escherichia coli in model group were significantly decreased(P<0.05).Compared with the model group,the contents of Bifidobacterium and Lactobacillus in intervention group 2 were increased and the content of Enterococcus was decreased while the contents of Lactobacillus and Escherichia coli in intervention group 1 were increased and the content of Enterococcus was decreased(P<0.05).Conclusion 1.It was found that Lactobacillus casei can significantly improve the antioxidant capacity and reduce oxidative damage;improve intestinal mucosal barrier and reduce intestinal mucosal permeability;regulate intestinal flora,optimize the structure of intestinal microflora in aging mice,and he lp maintain intestinal health,thus delay the aging process.2.Lactobacillus casei,as a useful probiotic supplements,is significant to promote human health.But the specific molecular mechanism of anti-aging effect by regulate intestinal flora and other aspects needed further study. |
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