| Objective To investigate the effects of probiotic Bifidobacteriumlactis M8 on rat lymphocyte subsets,T lymphocyte transformation and proliferation,immunoglobulin and some cytokines in a rat model of different immune status,to understand the effect of Bifidobacteriumlactis M8 on the immune function of rat models with different immune status,in order to discover the probiotic characteristics of the probiotics,and provide new ideas and basis for the future research and development of related foods and pharmaceutical preparations.Method 90 SPF clean-grade Wister rats,male and female,were randomly divided into three groups,namely,40 in experimental group A,40 in experimental group B,and 10 in blank control group.The rats were first given an adaptively administered Bifidobacterium lactis M8 powder(0.01 g,1 x 10~8 cfu)/d for 6 days.The experimental components were model control group(10),M8 low dose group(10),M8 medium dose group(10),and M8 high dose group(10).Among them,group B was given intramuscular injection of cyclophosphamide 40 mg/kg daily for 3 consecutive days,resulting in immunosuppression in rats.Group A was treated with the same method in group B to cause immunosuppression and then administered to rats daily by intranasal drip.A freshly prepared suspension of MRSA bacteria was instilled into the nasal cavity for 3 consecutive days,resulting in an immunosuppressive MRSA colonization rat model.After the model was completed,the divided dose group was intragastrically administered,the low dose group(0.01g,1×10~8 cfu)/d,the middle dose group(0.1g,1×10~9 cfu)/d,and the high dose group(1g,1×10~100 cfu)/d,continuous administration for 15 days,the model control group and the blank control group were given an equal volume of 0.9%sterile NaCl solution.On the 16th day,the rats were anesthetized and the blood was taken from the heart.The rats were sacrificed and the small intestine tissues were taken.The serum levels of immunoglobulin IgA and IgG,cytokines IL-2,IL-6,IFN-?and TNF-?were detected.The percentage of lymphocyte subsets and the proliferation of T lymphocytes were detected by immunohistochemistry.The expression levels of CD3~+and IgA~+molecules in the peyer's patches(PP)of each group were detected by immunohistochemistry.Result(1)The percentages of CD3~+T,CD4~+T,CD8~+T and NK cells in the experimental groups A and B.The difference between the high-dose group and the model control group was statistically significant(P<0.05).For B lymphocytes,high.The difference between the middle dose group and the model control group was statistically significant(P<0.05).(2)To analyze the effect of Bifidobacterium lactis M8 on the proliferation of T lymphocytes.Compared with the blank control group,the optical density values of the two experimental groups were increased and the difference was significant(P<0.05).(3)Compared with the model control group,both the high-dose and middle-dose groups of the A and B experimental groups can increase the serum levels of IgA,IgG,IL-2,IL-6,IFN-?,and TNF-?.Content(P<0.05).(4)The expression levels of CD3~+molecules and IgA~+molecules in the different doses of Bifidobacterium lactis M8 were compared with the model control group.The optical density values of the high dose group and the middle dose group in the experimental group A increased.The significance of the study(P<0.05),the optical density of the low dose group also increased,but the difference was not statistically significant(P>0.05).The optical density values of the three dose groups in the experimental group B increased,the difference was statistically significant(P<0.05).Conclusions By oral administration of Bifidobacterium lactis M8,the specific and non-specific immune response regulation ability of immunosuppressive and immunosuppressive MRSA-grafted rats can be improved to different extents,indicating that Bifidobacterium lactis M8 has a positive effect on promoting immune regulation. |
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