This study was carried out to evaluate the anti parasitic potential of silver, chitosan, and curcumin nanoparticles as anti-Giardia agents. Non-treated infected control rats were inoculated with Giardia lamblia cysts in a dose of 2 × 10(5) cysts/rat. Experimental group was infected then treated with curcumin, curcumin nanoparticles, chitosan, chitosan nanoparticles, and silver nanoparticles as single or combined therapy. The number of Giardia cysts in stools and trophozoites in intestinal sections were detected. Toxicity of nanoparticles was evaluated by comparing hematological and histopathological parameters of the normal control group and treated non-infected control group. The amount of silver was also measured in the liver, kidney, small intestine, lung, and brain of rats treated with silver nanoparticles. The number of the parasites in stool and small intestinal sections decreased in treated infected rats compared with infected non-treated ones. The effect in the single therapy was better with nanoparticles, and the best effect was detected in nano-silver. The combined therapy gave better results than single. Combination between nanoparticles was better than the combination of nano-forms and native chitosan and curcumin. The best effect was detected in combinations of nano-silver and nano-chitosan but with no full eradication. In conclusion, the highest effect and complete cure was gained by combining the three nano-forms. The parasite was successfully eradicated from stool and intestine. None of the treatments exhibited any toxicity. Accumulated silver in different organs was within the safe limits.

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The tight relationship between immunity and retinoid levels provides evidence on the critical role of retinoic acid (RA) in regulating immune activity, especially the mucosal one. Mucosal immune response is the key for determination of the outcome of infection, particularly against intracellular mucosal pathogens such as Toxoplasma gondii, where it plays a crucial role as a sentinel against parasite invasion. Herein, the immunomodulatory adjuvant role of RA was evaluated for prophylactic vaccination against chronic Toxoplasma infection. A quantity of 15 µg of RA pre-encapsulated with lipid-based nanoparticles (SLNs) was intranasally used in three doses, two weeks apart, as an adjuvant to the Toxoplasma lysate antigen (TLA). Afterward, mice were infected with 20 cysts of T. gondii (ME49 strain) and were sacrificed at the 4th week post-infection. Parasitological, immunological, biochemical, and histopathological studies were applied as vaccine efficacy measures. The protective role of the tested vaccine was noted using the statistically marked reduction in brain cyst count, accompanied by remarkable levels of protective IFN-γ and antibodies, with amelioration of infection-induced oxidative stress and brain pathology. Ultimately, this experiment outlined the prospective role of a novel, natural, nano-encapsulated and mucosal vaccine adjuvant RA-SLNs as a propitious candidate against chronic toxoplasmosis.

Melatonin (MLT) is now emerging as one of the universally accepted immunostimulators with broad applications in medicine. It is a biological manipulator of the immune system, including mucosal ones. MLT was encapsulated in solid lipid nanoparticles (SLNs), then 100 mg/kg/dose of MLT-SLNs was used as an adjuvant of Toxoplasma lysate antigen (TLA). Experimental mice were intra-nasally inoculated with three doses of different regimens every two weeks, then challenged with 20 cysts of T. gondii Me49 strain, where they were sacrificed four weeks post-infection. Protective vaccine efficacy was evident via the significant brain cyst count reduction of 58.6%, together with remarkably high levels of humoral systemic and mucosal anti-Toxoplasma antibodies (Ig G, Ig A), supported by a reduced tachyzoites invasion of Vero cells in vitro upon incubation with sera obtained from these vaccinated mice. A cellular immune response was evident through the induction of significant levels of interferon-gamma (IFN γ), associated with morphological deteriorations of cysts harvested from the brains of vaccinated mice. Furthermore, the amelioration of infection-induced oxidative stress (OS) and histopathological changes were evident in mice immunized with TLA/MLT-SLNs. In conclusion, the present study highlighted the promising role of intranasal MLT-SLNs as a novel mucosal adjuvant candidate against chronic toxoplasmosis.

Background: Maggot debridement therapy is a therapeutic wound myiasis that depends mainly on L. sericata larva. Owing to its availability and cheap breeding, M. domestica was suggested as an alternative to Lucilia. Objective: The present study was designed to assess the role of M. domestica larvae-derived substances on wound healing in immunocompetent and immunosuppressed mice. Material and Methods: Chitosan and gut extracts, obtained from M. domestica larvae, were applied daily on skin wounds of Swiss albino mice. Mice were divided into two groups, control non-treated mice (I), and experimental treated mice (II). Each group included immunocompetent (a), and immunosuppressed (b) mice. The experimental subgroups were treated with either chitosan (1) or gut extracts (2). Wounds were assessed by macroscopic evaluation, wound contracture, histopathological, immunohistochemical and bacteriological parameters. Results:In control non treated mice hair growth was evident with normal underlying skin by the end of the experiment (4 weeks) except in immunosuppressed (Ib) subgroup. Significant reduction in wound size was detected on the 7 th day post wounding (PW) in the immunocompetent-chitosan-treated subgroup (IIa1) compared to Ia, IIb1, and IIa2 subgroups. Histopathological examination showed early epidermal creeping on the 3 rd day PW in IIa1, IIa2, and IIb2 subgroups. Significant increase in collagen deposition was best detected in both gut extract-treated subgroups (IIa2 and IIb2) compared to the control subgroups (Ia, and Ib). Strong immunohistochemical reaction was evident in all immunocompetent treated mice (IIa1 and IIa2) by the 7 th day PW and in IIb2 by the 14 th day PW. Delay in keratin maturation was detected in both control subgroups and IIb1. Significant reduction in staphylococcal colonies was detected by the 7 th day PW in all immunosuppressed treated subgroups compared to their control subgroup (Ib). Conclusion:The difference in the rapid wound closure as detected by chitosan treatment, and the effective skin architecting by gut extract treatment recommends further trial by their combined therapy.

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