RESUMO
En el presente trabajo se evaluó la actividad tóxica de extractos de Eupatorium microphyllum L.F. sobre larvas de IV estadio del mosquito Aedes aegypti (Linneaus), bajo condiciones de laboratorio. Se utilizaron extractos acuosos en concentraciones del 500 mg L-1, 1.500 mg L - 1 y 2.500 mg L-1 y acetónicos en concentraciones de 10 mg L-1, 20 mg L-1, 30 mg L-1, 40 mg L-1 y 50 mg L-1. Los bioensayos se realizaron por triplicado, cada uno con 20 larvas, expuestas durante 24 horas a 150 mL de solución. En todos los ensayos biológicos se emplearon grupos control. En la evaluación de los extractos acetónicos, se empleó un control negativo para evitar que la mortalidad de las larvas ocurriera a causa del solvente. Los extractos acuosos mostraron acción moderadamente baja en la mortalidad de larvas, menor del 20%. Por el contrario, la acción de los extractos acetónicos se observó a 10 y 20 mg L-1, con 15% de mortalidad, mientras que a 30 y 40 mg L-1 se registraron 22 al 38% de mortalidad, en tanto que a 50 mg L-1 la mortalidad fue del 95,4% con resultados estadísticos altamente significativos. Las concentraciones de los extractos acetónicos mostraron ser las más eficientes para el control de los mosquitos seleccionados. Ambos tipos de extractos mostraron efecto tóxico en larvas de A. aegypti ; sin embargo, se observó mayor efecto en los extractos acetónicos en relación con los extractos acuosos de E. microphyllum, lo cual constituye una alternativa viable en la búsqueda de nuevos larvicidas a partir de compuestos naturales.
In the present work the toxic activity of extracts of Eupatorium microphyllum L.F. was evaluated on 4 th instar larvae of the mosquito Aedes aegypti (Linneaus), under laboratory conditions. Aqueous extracts were utilized in concentrations of 500 mg L-1, 1,500 mg L-1 and 2,500 mg L-1 and acetone in concentrations of 10 mg L-1, 20 mg L-1, 30 mg L-1, 40 mg L-1 and 50 mg L-1. The bioassays were carried out for triplicate each one with 20 larvae, exposed for 24 hours to 150 mL of solution. In all the bioassays were employed control groups. In the evaluation of the acetone extracts, a negative control was employed to avoid that the mortality of the larvae to occur on account of the solvent. The Aqueous extracts showed low moderate action in the mortality of larvae, less than 20%. On the contrary, the action of the acetone extracts was observed to 10 and 20 mg L-1 with 15% of mortality, while to 30 and 40 mg L-1 were registered 22 to 38% of mortality. However, to 50 mg L-1 the mortality was of 95.4% with highly significant statistical results. The concentrations of the acetone extracts showed to be the most efficient for the control of the mosquitoes selected. Both types of extracts showed toxic effect in larvae of A. aegypti, nevertheless, greater effect in the acetone extracts was observed relating to the aqueous extracts of E. microphyllum, which constitutes a viable alternative in the search of new larvicides from composed natural.
Assuntos
Animais , Eupatorium , Soluções , Solventes , Bioensaio , Aedes , ToxicidadeRESUMO
Introducción. Durante las últimas dos décadas, la terapia larval ha resurgido como una alternativa confiable y segura para la cura de úlceras cutáneas que no responden a los tratamientos convencionales. Objetivo. Evaluar el uso de las larvas de Lucilia sericata en el tratamiento de heridas infectadas con Pseudomonas aeruginosa en un modelo animal. Materiales y métodos. Se tomaron 12 conejos, los cuales fueron divididos al azar en 3 grupos homogéneos: al primero se le aplicó terapia larval, el segundo se trató con terapia antibiótica y el tercero fue establecido como control. A cada uno de los animales se les realizó una herida, luego se inoculó en ésta una suspensión de P. aeruginosa y, finalmente, al registrarse el desarrollo de la infección, se procedió, en los dos primeros grupos, a los tratamientos correspondientes. Para la evaluación macroscópica de las heridas, se tuvo en cuenta la presencia de edema y exudado, mal olor, inflamación alrededor de la herida y apariencia del tejido de granulación. Al proceso de cicatrización se le hizo seguimiento a través de una técnica dermohistológica. Resultados. Se registraron claras diferencias entre el grupo de animales tratados con terapia larval vs. el grupo tratado con terapia convencional de antibióticos, estableciéndose un periodo de 10 días para alcanzar la cicatrización en el grupo de terapia larval mientras que en el segundo grupo el proceso se cumplió en 20 días. Conclusiones. S e demostró la eficacia de las larvas de L. sericata en el tratamiento de heridas infectadas con P. aeruginosa.
Introduction. During the last two decades the larval therapy has reemerged as a safe and reliable alternative for the healing of cutaneous ulcers that do not respond to the conventional treatments. Objective. To evaluate the use of the larvae of Lucilia sericata as a treatment for infected wounds with Pseudomonas aeruginosa in an animal model. Materials and methods. Twelve rabbits were randomly distributed in 3 groups: the first group was treated with larval therapy; the second was treated with antibiotics therapy and to the third no treatment was applied, therefore was established as a control group. To each animal a wound was artificially induced, and then a suspension of P. aeruginosa was inoculated into the lesion. Finally, every rabbit was evaluated until the infection development was recognized and treatment was set up for the first two groups according with the protocols mentioned above. Macroscopic evaluation of the wounds was based on the presence of edema, exudates, bad odor, inflammation around the wound and the presence of granulation tissue. The healing process was evaluated by monitoring histological changes in the dermal tissue. Results. Differences in the time required for wound healing were observed between the first group treated with larval therapy (10 days) and the second group treated with conventional antibiotics therapy (20 days). Conclusion. The L. sericata larva is and efficient tool as a therapy for infected wounds with P. aeruginosa.
Assuntos
Animais , Modelos Animais , Pseudomonas aeruginosa , Terapêutica , Cicatrização , Ferimentos e Lesões , LarvaRESUMO
Morphology and cytochemistry of Aedes aegyptis cell cultures (Diptera: Culicidae) and susceptibility to Leishmania panamensis (Kinetoplastida: Trypanosomatidae). The first cellular line of Aedes aegypti was developed by Grace in 1966; afterwards, other cellular lines of this species have been generated. These have been used for the study of pathogenic organisms like viruses, bacteria and parasites, which demonstrates their importance in biomedical applications. This research describes, for the first time, some cytochemical characteristics of A. aegypti cell cultures, that were infected with (MHOM/CO/87CL412) strain of Leishmania panamensis. A morphological study of the cell culture was also carried out. Maintenance of the cell culture, parasites and infection in vitro were carried out in the Laboratory of Entomology, Cell Biology and Genetics of the Universidad de La Salle. The cell cultures infected with the parasite were maintained in a mixture of mediums Grace/L15, supplemented with 10 % fetal bovine serum (FBS) at pH 6.8 and a temperature of 26 ºC, during 3, 6 and 9 post-infection days. After this, these cell cultures were processed through High Resolution Light Microscopy (HRLM) and Transmission Electron Microscopy (TEM) based on standard protocols defined by the Group of Microscopy and Image Analyses of the Instituto Nacional de Salud. Semi-fine slices of 1 µm colored with toluidine blue were used for the morphological analysis of the culture, and ultra fine cuts of 60 to 90 nm stained with uranyl acetate and lead citrate where used for the ultrastructural study. In addition, PAS and peroxidase staining was carried out in cells fixed with methanol. The morphometric study was analyzed with software ImageJ (NIH). In the semi-fine slices, small cells were observed showing fibroblastic appearance 10.84±2.54 µm in length and 5.31±1.26 µm wide; other cells had epithelial appearance with a great peripheral nucleus, voluminous and vacuolated cytoplasm, 23.04±4,00 µm in length and 13.96±3.70 µm wide. These last ones predominated over the ones with fibroblastic appearance. Regarding the PAS coloration, 7.08 % of the cells presented abundant PAS positive cytoplasmatic granules which indicated polysaccharides presence. The peroxidase test gave a negative result. The greatest percentage of infection (18.90 %) of one total of 101 cells, turned up by day 6. Some cells analyzed by TEM presented a vacuolated aspect cytoplasm; some contained parasites, other fibrillar material and others were empty. The results indicate that A. aegypti cell culture can support the internalization and transformation of the parasite, which demonstrates the capacity that these cell cultures have to be infected with L. panamensis and to maintain the infection for approximately one week. Rev. Biol. Trop. 56 (2): 447-458. Epub 2008 June 30.
La primera línea celular de Aedes aegypti fue establecida por Grace en 1966 y desde entonces se han utilizado para el estudio de virus, bacterias y parásitos. En el presente trabajo se describen, por primera vez, algunas características citoquímicas de los cultivos celulares de A. aegypti, infectados con la cepa (MHOM/CO/87CL412) de Leishmania panamensis. También se realizó un estudio morfológico de las células del cultivo. Se observaron 30 células pequeñas con apariencia fibrolastoide de 10.84±2.54 µm de largo y 5.31±1.26 µm de ancho; otras 30 presentaron apariencia epitelioide con 23.04±4.00 µm de largo y 13.96±3.70 µm de ancho; éstas últimas predominaron sobre las de apariencia fibroblastoide. De 113 células, un 7.08%, presentaron abundantes gránulos citoplasmáticos positivos con la coloración de PAS, indicando presencia de polisacáridos. La prueba de peroxidasa dio un resultado negativo. El mayor porcentaje de infección (18.90%), de un total de 101 células, se presentó el día 6. Ultraestructuralmente, las células presentaron un citoplasma con aspecto vacuolado; algunas contenían parásitos, otras material fibrilar y otras estaban vacías. Los resultados indican que los cultivos celulares de A. aegypti pueden ser infectados por L. panamensis y mantener dicho proceso por aproximadamente una semana.