Estudos farmacocinéticos da forma recombinante da proteína P21 de Trypanossoma cruzi

Abstract

Trypanosoma cruzi is a flagellate protozoan and is among most successful intracellular parasites. During cell invasion process, occurs many associations between parasite surface molecules and receptors on surface of host cell occur. In this context, our research group, identified in T. cruzi, a new protein of 21 kDa, involved in the cellular invasion, designate P21. Recombinant form of P21 (rP21) is used in studies on biological aspects of T. cruzi providing elucidation of its function on protozoan infection, its relation in pathogen - host interaction and application in new diagnostic or treatment tests. In this regard, pharmacokinetic evaluations are essential for validation of these potential uses of protein. This work aimed to study the pharmacokinetics of recombinant protein rP21 related to its tissue distribution, elimination and stability after oral and subcutaneous administration in murine model. For this, were obtained rabbit polyclonal anti-rP21 antibodies, effective and with high protein specificity, in the ELISA and Western Blotting, at a 1: 200 dilution. After the 72-hour administration, the protein was present in serum samples from mice treated by the subcutaneous administration (50 and 200 pg) and was not detectable in feces and urine of the treated animals, indicating their distribution through bloodstream. Tissue distribution of the rP21 protein was observed by RIFI and only the stomach presented deposition of protein, with different behavior in each pathway. By oral route, the protein was visualized in the stomach glands, with the percentage of fluorescence being about 5x greater in animals treated with 200pg. By the subcutaneous administration, rP21 can be observed in the muscular tunica of stomach, with a percentage of fluorescence 20 times greater than in the control animals. These data indicate that this organ has receptors that cause the protein to bind to them. A difference in porcentage of tissue collagen was also observed in stomach when the animails was treated with 200pg of protein and had slight changes in the populationof the inflammatory system, but without tissue damage. The protein was also not degraded by the serum proteases of mice and did not miss its prophagocytic activities even after incubation for 24 hours with the serum proteases of the mice. Thus, our work demonstrates that the rP21 protein can be exploited to improve the diagnosis or treatment of Chagas disease, since it does not present toxicity to healthy tissues and can be administered to animals to perform a study on chronic phase of Chagas Disease. In addition, it remains stable even in the presence of serum proteases, remains in the bloodstream for a period, and is capable of binding to important organs in development of the disease.