title: Effects of selenium on Pteridium aquilinum and urethane-induced lung carcinogenesis.
abstract: The results of our previous study demonstrated that ptaquiloside, the main toxic agent found in Pteridium aquilinum, suppresses natural killer (NK) cell-mediated cytotoxicity. However, the ability of ptaquiloside to suppress the cytotoxicity of NK cells was prevented by selenium supplementation. NK cells play an important role in the innate immune response and have the ability to kill tumor cells. Therefore, we hypothesized that selenium may prevent the higher susceptibility to urethane-induced lung carcinogenesis that has been observed in mice treated with P. aquilinum. The immunosuppressive effects of ptaquiloside have been associated with a higher number of urethane-induced lung nodules in mice. Hence, we assessed the effects of P. aquilinum-induced immunosuppression on urethane-induced lung carcinogenesis in C57BL/6 mice that had been supplemented with selenium. For these experiments, mice were treated with both an aqueous extract of P. aquilinum (20 g/kg/day) and selenium (1.3 mg/kg) by gavage once daily for 14 days followed by a once-weekly intraperitoneal injection of urethane (1 g/kg) for 10 weeks that was accompanied by gavage 5 days a week. Lung adenomas in mice that had been treated with P. aquilinum plus urethane occurred with a frequency that was 44% higher than that in mice that had been treated with only urethane. In mice that had been supplemented with selenium and treated with P. aquilinum plus urethane, the occurrence of lung adenomas was reduced to 26%. These results suggest that selenium prevents the immunosuppressive effects of P. aquilinum on urethane-induced lung carcinogenesis.
authors: Department of Pathology, School of Veterinary Medicine and Animal Sciences, University of Sao Paulo , Sao Paulo , Brazil .
authors: Sheila B R
authors: SB
authors: Nakahara
authors: Daniel S
authors: DS
authors: Sanches
authors: Beatriz D
authors: BD
authors: Caniceiro
authors: Harry L
authors: HL
authors: Wysochi
authors: Graziela B
authors: GB
authors: da Silva
authors: Andreia O
authors: AO
authors: Latorre
mesh_terms: D000236:Adenoma / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D000818:Animals; D002273:Carcinogens / Q000494:pharmacology*; D019587:Dietary Supplements; D005260:Female; D007189:Indans / Q000009:adverse effects / Q000494:pharmacology; D008175:Lung Neoplasms / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D051379:Mice; D032498:Pteridium / Q000737:chemistry*; D012643:Selenium / Q000494:pharmacology*; D012717:Sesquiterpenes / Q000009:adverse effects / Q000494:pharmacology; D014520:Urethane / Q000009:adverse effects / Q000494:pharmacology
chemical_list: D002273:Carcinogens; D007189:Indans; D012717:Sesquiterpenes; D014520:Urethane; C043680:ptaquiloside; D012643:Selenium