Laminin P1 as biochemical marker in chemically induced colon carcinogenesis in rat
aESANEF, Université de Moncton, Moncton, NB, Canada, bCentre de Nutrition Humaine, Nancy, France
Aim: The purpose was to investigate the possible protective effect of different forms of supplemental calcium (carbonate, lactate and gluconate) in rats fed high saturated fat diets, by histological examination and by serum laminin P1 level. Methods: Wistar rats fed high fat diet (24%) were intra-rectally instilled (groups 1, 2, 3, and 4) with N-methyl-N-nitrosourea (NMU). Supplemental calcium (1.5% Ca++) complexed with either carbonate, gluconate or lactate, was administered in 2, 3, and 4 groups respectively (n=30 per group). They were compared to a control group 1 (n=29) without supplemental calcium. Colon carcinoma incidence was 25%, 24%, 10% and 7% in 1, 2, 3, and 4 groups respectively. The level evolution of serum laminin P1, was measured as a tumour marker by RIA at 4, 12, and 26 experimental weeks. Results: The serum laminin P1 level was significantly higher (p<0.0001) in NMU-instilled groups (1, 2, 3, and 4) than in the reference group T fed a standard diet and not NMU-instilled. Laminin P1 was increased in 90 % of rats with dysplasia and in 100 % of carcinoma bearing rats. Strong correlation was detected between the serum laminin P1 level and the carcinoma (r=0.83, p<0.001). Conclusions: Calcium as gluconate or lactate forms gives a best protective effect than carbonate salt and the serum laminin P1 may potentially be useful for detecting precociously experimental colon carcinogenesis.
Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Nice, France; February 7 - 10, 2004; in poster session 898 (Oncogenesis).