الفهرس 
Nano-Encapsulated MelatoninOnly 14 pages are availabe for public view
 |  | from | 99 |  |  |
| | | from | 99 | | |
Abstract
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) using the modified melt emulsification technique, then 100 mg/kg/dose of MLT-SLNs was used as an adjuvant of Toxoplasma lysate antigen (TLA).
Sixty Swiss albino strain mice were divided equally into five groups. Experimental mice were intra-nasally inoculated with three doses of different regimens every two weeks. To evaluate the efficiency of different studied regimens, six mice from each groups were sacrificed two weeks after the last immunization dose, while the remaining mice were 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 using scanning electron microscopy (SEM). Furthermore, the amelioration of infection-induced oxidative stress (OS) and histopathological changes were evident in mice immunized with TLA/MLT-SLNs compared to other studied groups. In conclusion, the present study highlighted the promising role of intranasal MLT-SLNs as a novel mucosal adjuvant candidate against chronic experimental toxoplasmosis.