Therapeutic and antioxidant potential of bionanofactory Ochrobactrum sp.-mediated magnetite and zerovalent iron nanoparticles against acute experimental toxoplasmosis

Abstract

The control of toxoplasmosis, a rampant one health disease, has been focussed on conventional antitoxoplasmic agents with their adverse outcomes, including serious side effects, treatment failure and emergence of drug resistant strains. Nanobiotechnology may provide a strong impetus for versatile alternative therapies against toxoplasmosis. Bionanofactory Ochrobactrum sp. strain CNE2 was recruited for the biosynthesis of functionalized magnetite iron nanoparticles (MNPs) and nanozerovalent iron (nZVI) under aerobic and anaerobic conditions and their therapeutic efficacy was evaluated against acute toxoplasmosis in murine model. The formation of self-functionalized spherical nanoparticles varied in size, identity and surface properties were substantiated. Mice were orally administered 20 mg/kg of each formulation on the initial day of infection and continued for seven consecutive days post infection (PI). Parasitological, ultrastructural, immunological, and biochemical studies were performed for assessment of therapeutic activity of biogenic iron nanoparticles (INPs). Parasitologically, MNPs showed the highest antitoxoplasmic efficacy in terms of 96.82% and 91.87% reduction in mean tachyzoite count in peritoneal fluid and liver impression smears, respectively. Lesser percentage reductions were recorded in nZVI-treated infected subgroup (75.44% and 69.04%). In addition, scanning electron microscopy (SEM) examination revealed remarkable reduction in size and extensive damage to the surface of MNPs-treated tachyzoites. MNPs-treated infected mice revealed a statistically significant increase in the serum levels of both interferon gamma (IFN-γ) to 346.2 ± 4.6 pg/ml and reduced glutathione (GSH) to 8.83 ± 0.30 mg/dl that subsequently exerted malondialdehyde (MDA) quenching action. MNPs showed a superior promising antitoxoplasmic activity with respect to both spiramycin (SPI) and nZVI. To best of our knowledge, this is the first study of a bio-safe oral iron nanotherapeutic agent fabricated via an eco-friendly approach that offers promising potential against acute experimental toxoplasmosis.

Fig 1

Visual (a) and optical properties (b) of INPs.

Fig 2

Structural properties of INPs: (a) XRD profile of MNPs; (b) XRD profile of nZVI; (c) EDX pattern of MNPs; (d) EDX pattern of nZVI.

Fig 3

Morphological and functional properties of INPs: (a) TEM of MNPs; (b) TEM of nZVI; (c) FTIR spectrum of MNPs; (d) FTIR spectrum of nZVI.

Fig 4

Particle surface properties of INPs: (a) Particle size distribution of MNPs; (b) Particle size distribution of nZVI; (c) Zeta potential of MNPs; (d) Zeta potential of nZVI.

Fig 5

SEM images of T. gondii tachyzoites recovered from peritoneal fluid of infected mice: (a & b) Non treated tachyzoites showing typical crescent shape and smooth body with intact regular membrane (x15,000); (c & d) SPI-treated tachyzoites showing minimal changes in the form of mild irregularities and few dimples on the crescent shape surface (x15,000); (e-f) MNPs-treated tachyzoites showed (e) markedly distorted body with multiple deep ridges and furrows (x15,000); (f) shrunken body and obvious protrusions (x15,000); (g-h) nZVI-treated tachyzoites showed (g) distortion of the posterior end with plasma membrane erosions and ulcerations (x15,000); (h) external protrusions and dimples (x15,000).

Fig 6. Serum IFN-γ levels among the different studied subgroups.