Efeitos in vivo e in vitro do isoflavonoide trifolirizina sobre o tumor de Ehrlich na sua forma ascítica

Abstract

This work evaluated the effect of the natural isoflavonoid trifolirhizin on the development of Ehrlich ascitic tumor in mice. The experimental model of Ehrlich ascites tumor (taE) was established by intraperitoneal injection of 5×106 tumor cells into the peritoneum of Swiss mice. Then, the effect of treatment with trifolirhizin (TRIFO) in vivo, and also in vitro on tumor cells and macrophages was evaluated. After 10 days of tumor inoculation, the analyzes were performed, and identified as the moment when the animals with taE exhibited an accumulation of ascitic fluid, culminating in an increase in the number of tumor cells and an increase in the number of leukocytes in the blood and in the bone marrow. The cell cycle profile evaluated by flow cytometry in ascitic fluid cells revealed an increase in cells in the S phase of the cell cycle. Furthermore, these cells were observed to produce high levels of ROS. In another group of experiments, from the 5th to the 9th day after the inoculation of the tumor cells, the animals received a daily injection of TRIFO (22.4 µM/kg/day), and after 24h of the last treatment it was observed that the TRIFO did not change the weight of the animals, the volume of ascites, or the abdominal area. In the total of peritoneal cells of animals with taE there was an increase in the count of mononuclear cells, neutrophils and also of tumor cells in the peritoneal fluid, without affecting the count of cells in the blood or bone marrow of animals with taE. Furthermore, TRIFO did not modify the cell cycle phases of tumor cells. Intracellular levels of ROS in ascites cells were reduced after treatment with TRIFO. In vitro, tumor cells exposed to TRIFO did not change baseline levels of NO or IL-8. Macrophages treated with TRIFO increased NO production, but without affecting the expression of TNF-α, IL-6, IL-10 and Arg-1. Therefore, it is concluded that the experimental model of taE in mice is feasible and reflects macro and microscopic parameters associated with the disease in humans. We found, for the first time, that TRIFO has effects that favor the inflammatory response by inducing leukocytosis in the ascitic fluid at the same time that it reduces the production of ROS in these cells and increases the generation of NO in macrophages. Taken together, these results indicate a potential for the isoflavonoid trifolyrizine to act as a modulator of inflammatory cell function in the tumor environment.