CONICET | Buscador de Institutos y Recursos Humanos

Introduction Since the beginning fungi and man are closely related each other. Mushroom consumption in Asia is due to its traditional culinary and medicinal interest. Base on ethno-medical selection, medicinal plants are traditionally used for therapeutic purposes, which have been the most effective technique for detection of new active compounds. Grifola frondosa (Maitake) mushroom has been collected for thousands of years in Japan, Korea, China and Russia. In 1998, Dr Namba identified a fraction obtained from both mycelium and fructified body of Maitake with the ability to stimulate macrophages. Epidemiological studies in Asia have shown that consumption of mushrooms specifically protects against breast and gastrointestinal cancer. The called D Fraction is a complex of polysaccharides (â-1,6-glucans and â-1 ,3-glucans) with high molecular weight about 1,000,000 daltons. It has been demonstrated that D Fraction induces activation of macrophages, neutrophils and NK cells (natural killer). In this work we were interested in to study the following aims: Determine if D Fraction obtained from the edible and medicinal mushroom Grifola frondosa can prevents or delay mammary tumor development in BALB/c mice. Compare the antitumor efficacy of different degrees of purification of the fraction D were our objective as well. Materials and methods We designed an experimental analytical prospective longitudinal study, employing sixteen 6 weeks old BALBc mice. The mice population was divided into 3 groups: a control group containing 6 mice, and two treatment groups containing 5 mice each. The treatments were administered intraperitoneally with 5 mg/Kg/day of PRO 4x (Mushroom Wisdom) or Grifron D (Maitake Products) for 15 days. Controls were injected with PBS. After treatment period, all mice were injected i.p with 4x105 murine tumor cells LM3 to induce mammary tumorigenesis. Animals were daily checks by visual examination and abdominal palpation to found tumors. After 30 days, all mice were sacrificed. Under dissection were evaluated several organs and the mammary tumors and the normal breast tissue were isolated in each mice. Results The incidence of breast cancer was 100% in the control group. Five out of 6 mice in the control group develop breast tumor after 10 days of tumor induction and the remaining mice develop tumor at day 12th. In the group treated with Grifron D, two mice developed tumor (40% incidence) at 14° and 20° days after tumor induction, respectively. Cero out of five mice, in the treated group with PRO 4X, develop tumor (incidence 0%) after 30 days of tumor induction. Conclusions Maitake Fraction D, effectively, prevents mammary tumor development in BALB/c mice. In this experiment Maitake D-Fraction PRO 4X showed the maximum antitumor power with 100% inhibition in mammary tumor development. Maitake Grifron D, on the other side, had shown a 60% tumor development inhibition. The incidence of 100% in the control group showed the clear cell malignancy of LM3 cell line. The next histological evaluations and gene expression analysis on isolated tissues will allow us to elucidate the molecular mechanisms by which â-glucans prevent mammary carcinogenesis.