Objective: To explore the effect of bifidobacterium adolescence on prevention from experimental colorectal carcinoma and its antitumor mechanism.
Methods: An animal model of nude mouse tumor transplanted from colorectal carcinoma was set up. Bifidobacteria adolescence were intraperitoneally injected into nude mice in advance. The growth rate, ultrastructure, density of apoptotic cells, rate of bcl-2 and bax oncoprotein expression and its positive cell density in transplanted tumor of nude mice from colorectal carcinoma were investigated by employing transmission microscopy, in situ end labeling technique and immunohistochemical staining.
Results: The growth rate of transplanted tumors from colorectal carcinoma in the group with bifidobacterium prevention was slower than that in the control group. Many tumor cells at varied apoptotic stages could be observed in transplantation tumor tissue in the bifidobacterium prevention group and their density of apoptotic cells, rate of bcl-2 and bax oncoprotein expression and its positive cell density were significantly higher in the group with bifidobacterium prevention, as compared with the control group (P < 0.01). But, expression rate of bcl-2 oncoprotein turned contrary to that of bax oncoprotein.
Conclusion: Bifidobacteria adolescence could markedly prevent from occurrence and development of colorectal carcinoma in vivo and induce apoptosis of tumor.