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

Summary

Optimization of the experimental hamster model for cutaneous leishmaniasis by intradermal injection of Leishmania promastigotes at the dorsal skin. This approach is useful during inoculation, follow-up, characterization of lesions, application of treatments and obtaining of clinical samples. Locomotion, search for food and water, play and social activities are preserved.

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 l0⁷ 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.

Protocol

1. Infection of Hamsters

1. Animals

Inbred 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 disti....

Discussion

Cutaneous leishmaniasis is endemic in the tropics and neotropics. It is often referred to as a group of diseases because of the varied spectrum of clinical manifestations, which range from small cutaneous nodules to gross mucosal tissue destruction. Most available drugs are costly, require long treatment regimens and are becoming increasingly ineffective, necessitating the discovery of new drugs.

The mouse model is widely used but has some disadvantages. Thus for example, on the basis of the l.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Ketamine	Reagent	Holliday –Scott S.A
Xilacine	Reagent	Synthesis
PBS	Reagent	GIBCO, by Life Technologies	14190-136
Digital caliper	Equipment	Fisher Scientific	15-077-958
Giemsa	Reagent	Sigma-Aldrich	GS1L-1L
Formalin	Reagent	Nova lab	11273
Paraffin	Reagent	Pechiney Plastic Packaging	PM-996
Haemotoxilin	Reagent	Nova lab	10870103
Eosin		Nova lab	10870203
Kodak Ektachem dry chemistry	Equipment	Kodak Ektachem	DT-60
meglumine antimoniate	Reagent	Aventis
Microscopy	Equipment	Nikon Instruments	YS2-T