Chemotherapeutic Efficacy and Safety of Diminazene Aceturate-Chloroquine Sulphate Combination as an Antileishmanial Drug in Balb /c Mice

Mwololo, Samuel Wambua (2014) Chemotherapeutic Efficacy and Safety of Diminazene Aceturate-Chloroquine Sulphate Combination as an Antileishmanial Drug in Balb /c Mice. Masters thesis, Kenyatta University.

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Abstract

Leishmaniases are a complex disease caused by at least 22 different species of protozoan parasites belonging to the genus Leishmania. They are significant causes of morbidity and mortality in 88 countries around the world. The clinical manifestations range from self healing cutaneous and mucocutaneous skin ulcers to fatal visceral form. The use of most antileishmanial drug agents has however been limited because of their toxicity, high cost and declined efficacy due to high resistance and relapse rates. To improve the management of leishmaniasis, alternative chemotherapeutic strategies are required. Combination therapy of antileishmanial drugs is currently considered as one of the rational approaches to lower treatment failure rate and limit drug resistance spreading. The objective of this study was to evaluate the safety and efficacy of a combination between diminazene (Dim) and chloroquine (Chq) as a potentially effective, low cost chemotherapy against visceral leishmaniasis. The experiment involved both in vitro and in vivo evaluations. In vitro drug efficacy involved incubation of L. donovani promastigote cultures in 96- well plates with various concentrations of test drugs for 72 hours and calculating drug concentration inhibiting half the number of parasites (ICso).Toxicity evaluation involved incubation of Vero cell lines in culture with various concentrations of test compounds for 72 hours and determination of drug concentration killing half the number (LDso) of Vero cells. For in vivo evaluation, BALB/c mice were infected with L. donovani promastigotes and kept for five weeks for establishment of disease. Uninfected (Naive) mice were included in the experiment. Following disease establishment, mice divided in to groups of 8 animals were treated with either, Diminazene (Dim), Chloroquine(Chq), or Diminazene -Chloroquine (Dim-Chq) at doses of 12.5 mg/kg. A fourth group was treated with standard reference drug, Amphotericin B (Amphot B) at doses of 1 mg/kg. While group five mice were not treated and these served as a control. reatments started 7 weeks post infection and were delivered intraperitoneally daily for 21 days. Body weight measurements were taken before infection, 37 days post infection and 7 days after treatment. Seven days after treatment, all mice were sacrificed and IgG antibody responses and splenic parasite loads determined. Antibody responses were quantified by enzyme linked immunosorbent assay (ELISA) while parasite burden was done microscopically by scoring the number of amastigotes in splenic impression smears per 500 cell nuclei. Data were analysed with one way analysis of variance (ANOVA), Tukey-Kramer test, spearman rank correlation test or student t-test. In vitro results indicated that dim-chq was at least 9 times more effective than single drugs in inhibiting promastigote growth in culture (lCso = 0.49 ± 0.24). Dim-Chq was as toxic as Dim (Ldso = 0.02 ± 0.01). In vivo evaluation indicated that, infection of BALB/c mice with L. donovani resulted in increase in body weight as measured 37 days post infection (P = 0.007). Of the test drugs, Dim-Chq was associated with the least IgG responses. There was no significant change in body weights for various mice groups following treatments (P = 0.1615). Treatment with Dim-Chq significantly protected mice against visceral leishmaniasis as compared to single drug therapies (P = 0.001). However, Amphot B was more effective against disease than any other drug compound (P = 0.0001). High antibody responses were significantly associated with severe disease (r = 1.000; P = 0.0167). The study concludes that Dim-chq is more safe and efficacious than single drugs and may be developed further for control against human visceral leishmaniasis. In addition, antibody levels may be used as a diagnostic and prognostic tool in this model.

Item Type: Thesis (Masters)
Subjects: Q Science > QL Zoology
R Medicine > RM Therapeutics. Pharmacology
Divisions: Africana
Depositing User: Tim Khabala
Date Deposited: 04 Sep 2017 14:10
Last Modified: 04 Sep 2017 14:10
URI: http://thesisbank.jhia.ac.ke/id/eprint/1940

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