Possible chemopreventive effects of bovine lactoferrin on esophagus and lung carcinogenesis in the rat

A milk component, bovine lactoferrin (bLF), previously shown by us to he a strong: chemopreventive of colon carcinoma development, was examined for it s influence on other organs using a rat multi-organ carcinogenesis model. M ale F334 rats, aged 6 weeks, were treated sequentially with diethylnitrosam ine (DEN, i,p,), dihydroxy-di-N-propylnitrosamine (DHPN, in drinking water) and N-nitrosomethylbenzylamine (NMBA, s,c,) during the first 8 weeks (DDN treatment), and then bLF was administered in the basal diet, at a dose of 2 , 0.2, 0.02 or 0.002%. Other groups were given DDN treatment or bLF alone a s controls. All surviving animals were killed at week 41, and major organs were examined histopathologically for neoplastic lesions, In the esophagus, a tendency for reduction in development of papillomas was evident in the b LF-treated animals, along with a significant suppression of relatively larg e-sized papillomas (more than 50 mm(3) volume) at the 0.2% dose (P<0.05, 11 % of the control). The multiplicity of tumors (adenomas and carcinomas) in the lung was also decreased in animals fed 0.02% bLF (1.98+/-0.11 per cm? l ung tissue section, P<0.05) compared to the control group (3.48+/-0.33). No enhancing or inhibitory effects of bLF on tumor development in other organ s were noted, The present results indicate that bLF exerts chemopreventive effects in the esophagus and lung in addition to the colon.