Inhibition of Murine Systemic Leishmaniasis by Acetyl Salicylic Acid via Nitric Oxide Immunomodulation

Abstract

Background: The purpose of this study was to evaluate antileishmanial effects of ASA via NO pathway in Leishmania major infected Balb/c mice. Moreover, toxicity and pathological consequences of ASA administration were investigated.

Methods: Balb/c mice were infected with L. major and ASA was inoculated orally after lesion appearance for its ability to modulate NO and to modify Leishmania infection in host, in order to evaluate the effects of NO production on size and lesion macroscopy, delay of lesion formation and proliferation of amastigotes inside macrophages. Liver, spleen, and lymph nodes were also studied as target organs to detect amastigotes. In addition, plasma was investigated for NO induction using Griess microassay.

Results: ASA increased NO production in plasma of both naïve and Leishmania test groups at the ultimate of the experimental period. A decline was observed in proliferation of amastigotes inside macrophages of test group when compared with control one. ASA reduced lesion size, inhibited Leishmania visceralisation in spleen, lymph node, and decreased hepato/splenomegaly in ASA treated animals.

Conclusions: Some antileishmanial effects of ASA by NO-modulation were indicated during systemic leishmaniasis in mice. Despite slight effects on lesion size, ASA decreased parasite visceralization in target organs and declined their proliferation inside macrophages. Therefore, ASA may be indicated to inhibit systemic leishmaniasis via NO pathway in mice model.

Keywords: ASA; Balb/c; Immunotherapy; Leishmania major; NO.

Fig. 1

NO Production in plasma of experimental groups of Balb/c mice. NO Production was measured by GMA in plasma of entire groups at the end of the experimental period. Significant analysis (٭٭P<0.01, ٭٭٭P<0.001) was determined by Student's t-test using Graph Pad Prism (n=10 mice/group)

Fig. 2

Comparative proliferation of amastigotes inside MQs of CL lesions from L. major infected mice. The proliferation of parasite was evaluated by counting amastigotes inside random MQs on Geimsa stained smears of CL lesions in Leishmania group at the end of the experimental period. Significant analysis (٭٭٭P<0.001) was determined by Student's t-test using Graph Pad Prism (n=10 mice/group)

Fig. 3

ASA effects on lesion size and comparison with control of Leishmania group Significant difference (٭٭P<0.01, ٭٭٭P<0.001) was determined by Student's t-test using Graph Pad Prism (n=10 mice/group)

Fig. 4

Amastigotes in smears of target tissues in mice infected with L. major The percentage of positive smears was compared between control and test groups of lesion, and target tissues. Significant differences (٭P<0.05, ٭٭P<0.01) was determined by Student's t-test using Graph Pad Prism (n=10 mice/group) As a side effect of ASA application, a reduction up to 30% in survival rates was found in naïve and Leishmania test groups after 11 weeks of infection and a slight weight loss (P<0.05) was observed in both naïve and Leishmania test groups after 6 weeks of inoculation.

Fig. 5

ASA effects on hepatomegaly and splenomegaly in naïve and Leishmania groups Significant variation (٭P<0.05) was detected by Student's t-test using Graph Pad Prism (n=10 mice/group)