Investigation and isolation of Leishmania: cryopreservation of samples of biopsies from skin lesions in experimental Cutaneous Leishmaniasis

Abstract

We investigated the viability of isolation of Leishmania (V.) braziliensis and L. (L.) amazonensis from cryopreservated, at -20°C, -70°C and -196°C, samples of biopsies of hamsters (Mesocricetus auratus) experimentaly infected. Biopsies with 2mm of diameter were obtained from feet lesions of hamsters. Half of the biopsies was conditioned in plastic freezing tubes containing 1.0 ml of sterile salt solution and 0.l ml of glycerol. The rest was macerated in sterile salt solution and conditioned in aliquot of 1.0 ml into plastic freezing tubes containing 0.l ml of glycerol. It was constituted, then, 3 groups, so that each group contained a biopsie or macerated sample belonging to the different Leishmania at the temperatures above mentionated. Every group were cooled at 4°C for overnight, then placed at -20°C for 24 hours, where stayed the group 1 for 60 days. The other plastic freezing groups were placed at -70°C for 24 hours where stayed the group 2 for 60 days, being the group 3 placed at -196°C where continued for 60 days 100. After this period, the samples were thawed and examined from the smears, cultures and inoculation of these materials. The results obtained up to the present indicated the surviving and the cultivability of L. (L.) amazonensis at -20°C and -l96°C and L. (V.) braziliensis at -20°C, both strains in macerated and fragment.