Effects of casein glycomacropeptide on the early development of primary colorectal cancer in rats

In this paper, we utilized dimethylhydrazine (DMH)-induced colorectal cancer (CC) model rats to explore the effects of casein glycomacropeptide (CGMP) on colorectal cancer. Rats with CC were orally administrated with 10, 50, or 100 mg/kg bw d CGMP, or the same volume of phosphate-buffered saline for 15 weeks. The total numbers of aberrant crypt foci (ACF) and crypts per focus in colon were scored using a light microscope at low magnification after the colon was stained with methylene blue solutions. The methylation level of DNA extracted from colon was detected using methylation-specific PCR. The expression of p16 and mucin 2 (MUC2) proteins were measured by immunohistochemistry. The results showed that although ACF were found in rats treated with CGMP, their number was significantly decreased compared to that of model rats. In addition, methylation and expression levels of p16 and MUC2 were also inhibited by CGMP, which were more obvious in rats treated with 50 mg/kg bw d CGMP. In conclusion, CGMP has potential application as nutritional therapy for preventing colorectal cancer.