Influence on the growth of human colon cancer xenograft in nude mice and immune function in KM mice by Lactobacillus fermentum

Objective To investigate the inhibitory growth effect of lactobacillus fermentum(Lb-f) on human colon cancer xenograft in nude mice and its mechanism.Methods Therapeutic trial of human colon cancer cell xenograft in nude mouse model was used to investigate the growth inhibitory effect of Lb-f on human colon cancer.The method of clearance of carbon particle and augment of thickness of voix pedis and the assay of antisheep akaryocyte agglutinin antibody titer were used to examine the regulation effects of Lb-f on cell immunity and humoral immune function in KM mice.Results After treatment with Lb-f,the growth inhibitory rates of human colon cancer cell xenograft in nude mice were 63%,79% and 83%;the weight inhibitory rates of xenograft were 44%,49% and 71%;the values α of adjustable clearance index of carbon particle in KM mice were 2.3928±0.3941,3.4092±0.1711,4.5036±0.2157,1.9350±0.8839(P 0.05);the values of the difference of thickness of voix pedis were(1.01±0.07)mm,(1.37±0.09)mm,(2.01±0.14)mm,(0.45±0.05)mm(P 0.001);the values of the antibody titer of hemagglutinin of antisheep in mice were 336±176,544±154,832±309,100±43(P 0.01).Conclusion The inhibitory growth effect of Lb-f on human colon cancer HT-29 cell xenograft in nude mice is associated with the promotion of the immune function.