Natural anthraquinones-mediated photodynamic inactivation: preliminary results against Leishmania amazonensis-induced cutaneous leishmaniasis in mice

SUSANA C. NÚÑEZ MONTOYA; JESICA A. DIMMER; JOSÉ LUIS CABRERA; FERNANDA V. CABRAL; MARTHA S. RIBEIRO

Viña del Mar

Encuentro; XIV Encuentro latinoamericano de fotobiología - ELAFOT; 2019

Universidad Catolica de Chile; Universidad Andres Bello; Universidad de Santiago de Chile; Universidad de Chile

Cutaneous Leishmaniosis (CL) is one of the 17 neglected tropical disease classified by World Health Organization produced by Leishmania parasites. Following a sandfly bite in exposed areas of skin, a pink papule progresses to a nodule or plaque and eventually forms an ulcer with raised borders. So far, there is no effective treatment without toxicity and resistance.1 Photodynamic inactivation (PDI) appears as a promising topical treatment to overcome this serious health problem. This therapy combines photosensitizers, as natural anthraquinones (AQs), and proper light to produce reactive oxygen species and kill Leishmania parasites.2 A recent in vitro study demonstrated that Soranjidiol (Sor), Bisoranjidiol (Bisor) and 5-Chlorosoranjidiol (5-Clsor) irradiated with LED at 20 J/cm2, reduced above 90% the promastigote viability of Leishmania amazonensis.3 The aim of this work was to conduct a pilot study on infected mice to verify the effect of AQs-mediated PDI on CL.Twelve Balb/C mice were infected in the left footpad with a suspension of 1x106 promastigotes/ml and randomly divided into four groups: control (without treatment), G1 (Sor and blue LED, 410 ± 10 nm), G2 (Bisor and blue LED) and G3 (5-Clsor and green LED, 520 ± 10 nm). All AQs were assayed at 10 μM and LEDs were set to deliver a fluence of 45 J/cm2 (15 min). After treatment, parasite burden was determined by bioluminescence every day for 72 h and evolution of lesion and pain was followed during a month, measuring once a week.Results showed that treatment with AQs tend to maintain parasite burden for 48 h after PDI, whereas 72 h post PDI, only 5-Clsor continue keeping low levels of parasite burden. Regarding lesion size and pain, no statistically significant differences were noticed among groups. However, one week after PDI, only the group treated with Sor has no ulceration on the lesion. In conclusion, our results suggest that Sor is the most promising AQ to pursue the best protocol to treat cutaneous leishmaniasis, since it not only maintained the parasite burden for 48 h after PDI, but it also prevented ulceration in the lesion one week after PDI.