Exhaustive physical exercise increases the number of colonic preneoplastic lesions in untrained rats treated with a chemical carcinogen.
Aberrant crypt foci (ACF) have been used for early detection of factors that influence colorectal carcinogenesis in rats. It has been observed that exhaustive exercise increases free radical DNA oxidative damage and depresses immune function, events also related to the increased risk for cancer development. Fifteen days after a single exhaustive swimming bout in untrained rats treated with a colon carcinogen, we observed a statistically significant increased number of ACF when compared to the non-exercised group. Thus, we concluded that exhaustive exercise increased the susceptibility for colon cancer in rats. From our finding and literature data, we hypothesize that, similarly to the suggested relationship between exercise and infections, exercise could be protective against cancer or it could increase the risk for this disease depending on its type, dose and duration.
Demarzo
Marcelo Marcos Piva
MM
Department of Pathology, Ribeirão Preto Medical School, University of São Paulo, USP, 3900 Bandeirantes Avenue, 14049-000 Ribeirão Preto, SP, Brazil.
Garcia
Sérgio Britto
SB
D000818:Animals; D002471:Cell Transformation, Neoplastic; D003110:Colonic Neoplasms / Q000503:physiopathology* / Q000662:veterinary; D004195:Disease Models, Animal; D005221:Fatigue; D007239:Infections / Q000150:complications; D008297:Male; D010805:Physical Conditioning, Animal; D011230:Precancerous Conditions / Q000503:physiopathology*; D051381:Rats; D017208:Rats, Wistar; D012307:Risk Factors