Cutaneous Leishmaniasis in the Dorsal Skin of Hamsters: a Useful Model for the Screening of Antileishmanial Drugs

Abstract

Traditionally, hamsters are experimentally inoculated in the snout or the footpad. However in these sites an ulcer not always occurs, measurement of lesion size is a hard procedure and animals show difficulty to eat, breathe and move because of the lesion. In order to optimize the hamster model for cutaneous leishmaniasis, young adult male and female golden hamsters (Mesocricetus auratus) were injected intradermally at the dorsal skin with 1 to 1.5 x l0 7 promastigotes of Leishmania species and progression of subsequent lesions were evaluated for up to 16 weeks post infection. The golden hamster was selected because it is considered the adequate bio-model to evaluate drugs against Leishmania as they are susceptible to infection by different species. Cutaneous infection of hamsters results in chronic but controlled lesions, and a clinical evolution with signs similar to those observed in humans. Therefore, the establishment of the extent of infection by measuring the size of the lesion according to the area of indurations and ulcers is feasible. This approach has proven its versatility and easy management during inoculation, follow up and characterization of typical lesions (ulcers), application of treatments through different ways and obtaining of clinical samples after different treatments. By using this method the quality of animal life regarding locomotion, search for food and water, play and social activities is also preserved. Video LinkThe video component of this article can be found at http://www.jove.com/video/3533/ Protocol 1. Infection of Hamsters AnimalsInbred female and male golden hamsters (Mesocricetus auratus), 6-8 weeks, weighing 140-160 g are used. They are housed at the animal facility, in temperature-controlled accommodation, fed with standard rodent dried food and provided with water ad libitum. All the procedures involving animals are approved by the institutional Ethical Committee for Experimental Animal Use. Before experimental infection with dermotropic Leishmania parasites animals are sexed, marked and weighted according to standardized procedures. For sexing, animals are inspected for distinctive features such as the visualization of the mammary line and the short ano-genital distance in females, or the visualization of testicles and a greater distance between the anus and foreskin in males. Then, animals are marked by ear piercing or by staining an area of the skin with a swab soaked in picric acid. For ear perforation, after clean with 70% alcohol the ear is pierced using an ear punch for rodents. A region with blood vessels must be avoided. Sedation or anesthesia with a mixture 9:1 of Ketamine (50 mg/kg) and Xilacine (20 mg/kg) intraperitoneally in a volume of 260-300μl 25-G needle is recommended. Finally, animals are weighed by placing them in a trap or box that is conditioned on a precision balance. ParasitesPromastigotes of dermotropic Leishmania species, such as L. amazonensis, are cultured in biphasic Novy-MacNeal-Nicolle (NNN) culture medium at 26°C. Metacyclic (station...

New strategy to improve quality control of Montenegro skin test at the production level

“…Fifthly, hamsters have strait dorsal compared to guinea pigs, making it difficult to organize the skin test inoculation sites. Furthermore, guinea pigs need be immunized with dead parasites (parasite proteic extract) and do not develop the disease, while hamsters need to be infected (live parasites) to respond to skin test 8,9,14 . Once immunized, the risk of contamination is reduced, and the time needed to develop an immune response is faster than that of hamsters (guinea pigs = 30 days; hamsters = minimum of 45 days).…”

“…Secondly, to validate C. porcellus as a suitable animal model, Mesocricetus auratus, which is considered a susceptible bio model for infection with Leishmania sp. 8,9 , was chosen. …”

Development of a Novel Formulation with Hypericin To Treat Cutaneous Leishmaniasis Based on Photodynamic Therapy inIn VitroandIn VivoStudies

“…The toxicity of 0.5% hypericin cream or MA was evaluated according to hepatic and renal functions of hamsters in treated and untreated animals as described previously (32). At TD0 and day 8 of treatment (TD8), blood was drawn from the heart, and serum was separated by centrifugation at 5,000 ϫ g for 2 to 3 min.…”

“…The therapeutic response of a 0.5% hypericin topical cream was tested in the hamster (Mesocricetus auratus) model for CL (32). Briefly, previously anesthetized (40 mg/kg ketamine and 5 mg/kg xylazine) hamsters were inoculated in the dorsal skin with promastigotes of L. panamensis (5 ϫ 10 8 parasites/ 100 l phosphate-buffered saline [PBS]).…”

In Silico Screening of Potential Drug with Antileishmanial Activty and Validation of their Activity by in Vitro and in Vivo Studies

“…The toxicity of treatments was evaluated by comparingthe blood levels of ALT (alanine amino transferase), BUN (blood urea nitrogen) and creatinine using commercially available kits (Biosystems, Spain) as described by others [24]. At days D0 and day 8 of treatment (D8), blood was drawn from the hearth and serum was separated by centrifugation at 5,000 g for 2-3 min.…”