Effects Of Casein Glycomacropeptide(CGMP) On Primary Colorectal Cancer In Rats

Because of the rapid developing in economy and changing food habits,there was an increasing trend yearly at colorectal cancer in our country.Colorectal cancer ranks the third as a cause of death from cancer overall.It is clearly important tounderstand the basis of carcinogenesis and tumorgenesis of this cancer,and to develop effective molecular diagnostic methods for early detection and therapeutic intervention in colorectal cancer.It is an effectively method to prevent cancer by ingesting natural food.CGMP as one kind bioactive peptide.The relationship of CGMP and colorectal cancer is being paid close attention at home and in abroad.This study was designed to determine the protective effect on colorectal cancer of CGMP at different doses through the observertion of ACF,p16 gene DNA methylation change in tissne,and investation of p16 ptotein expression and Muc2 expression.Female Wistae rats were randomly divided into 5 groups: negative control group,model group and three different CGMP added groups with the dose of10mg/kg/,50mg/kg,100mg/kg(n=10 each group).All of the rats were killed15 weeks later and colons of rats were removed,and the total numbers of ACF as wellas the number of crypts per focus were scored using a light microscope at low magnification after methylene blue soloution,then to extract DNA,after DNA modification was detected by methylation-specefic PCR.p16 and MUC2 protein expression were measured by immunohistochenmistry(IHC).The results show:(1)during the whole study,there was no significant difference between each groups of their body weigh.(2)ACF were diseovered in both of the model group and in CGMP groups.but control group was no ACF formation.The number of ACF in normal control rats is 33.1±3.1,and the number of different CGMP administration doses are 27.8±4.5,22.8±5.4,20.6±1.9.Compared to model group,CGMP groups inhibited the formatation of ACF significantly.(3)hypermethylation of p16 was detected in 0%?80%(8/10)?70%(7/10)?40%(4/10)?50%(5/10)in normal mucos,colorectal cancer tissues,three different CGMP doses respectively.Comparedto model group 50mg/kg CGMP group inhibits p16 methylation change significantly.(4)IHC anylysis demonstrated a significant difference among CGMP groups and model groups in p16 and MUC2 protein expression,and in normal controls are overexpressed.