Mechanisms of the effectiveness of poly(ε-caprolactone) lipid-core nanocapsules loaded with methotrexate on glioblastoma multiforme treatment.

PURPOSE: The low penetration of drugs across the blood-brain barrier (BBB) compromises the delivery of chemotherapeutic agents to the brain parenchyma and contributes to the poor prognosis of glioblastoma multiforme (GBM). We investigated the efficacy of methotrexate-loaded lipid-core nanocapsules (MTX-LNC) administered by the oral route to treat murine GBM, its ability to cross the BBB, and the mechanisms of MTX-LNC uptake by cultured GL261 glioma and BV2 microglia cells. MATERIALS AND METHODS: Female C57B/6 mice were used in intravital microscopy assays to investigate the penetrance of rhodamine B-label MTX-LNC (RhoB/MTX-LNC) in the brain after oral or IV administration, and to evaluate the BBB integrity. Intracranial implantation of GL261 cells was undertaken to induce a murine GBM model, and the effectiveness of oral MTX or MTX-LNC treatments (started on Day 10 of GBM, every 2 days for 12 days) was quantified by tumor size, body weight, and leukogram. Pharmacological blockade of endocytic pathways was done to investigate the mechanisms of MTX-LNC uptake by cultured GL261 and microglia BV2 cells by using fluorescence microscopy. The effect of MTX-LNC or MTX on GL261 and BV2 proliferation was evaluated to compare the cytotoxicity of such compounds. RESULTS: RhoB/MTX-LNC was detected in brain parenchyma of mice after IV or oral administration, without any damage on BBB. Oral treatment with MTX-LNC reduced tumor volume and prevented weight loss and leukopenia in comparison to MTX-treated mice. MTX-LNC uptake by GL261 is caveolae-dependent, whereas endocytosis of MTX-LNC by BV2 occurs via phagocytosis and macropinocytosis. Both MTX-LNC and MTX reduced GL261 and BV2 proliferation; however, MTX-LNC showed higher efficacy in the inhibition of glioma proliferation. CONCLUSION: Together, we infer that the higher ability of MTX-LNC to cross the BBB and be captured by cancer and immune brain cells by different mechanisms is responsible for the higher efficacy of oral MTX-LNC treatment in GBM.

Deltamethrin as inductor agent of precocious ovarian degeneration in Rhipicephalus sanguineus s.l. (Acari: Ixodidae) ticks.

The cosmopolitan species Rhipicephalus sanguineus s.l. is one of the most widely distributed ticks all over the world. These ectoparasites are vectors of several pathogens and cause significant direct damage to their hosts. The biological success of these ectoparasites has been attributed to their ovaries and salivary glands, organs that ensure their survival in various environmental conditions. The importance of the ovaries in ticks is that, after mating, the individuals are able to lay approximately three thousand eggs. The present study had the objective to demonstrate the effects of deltamethrin obtained from the product Butox P CE 25® (MSD Saúde Animal, São Paulo, Brazil) on the ovarian development of R. sanguineus s.l. females. The chemical was tested in the concentrations of 25, 50, 100 and 200 ppm (respectively 80, 40, 20 and 10 times lower than the recommended by the manufacturer). Through the application of histological techniques and HE staining, the results showed that the deltamethrin was potentially able to modify the morphophysiology of the oocytes in all developmental stages, interfering in the vitellogenesis, causing intense vacuolation, cytoplasmic disorganization, and alterations in the chorion secretion. In addition, the chemical affected the germ vesicle of some oocytes, causing damages and hypertrophy, fragmenting the chromatin and forming bodies strongly stained by hematoxylin. Therefore, this study confirmed that the deltamethrin had an important action on the reproductive system of the R. sanguineus s.l. females, causing the precocious structural disorganization of the germ cells, consequently preventing the generation of new individuals.