Evaluation of the effect of guanabenz-loaded nanoparticles on chronic toxoplasmosis in mice.

Chronic toxoplasmosis which is positively correlated with many neuropsychiatric problems has no curative treatment till now; due to the resistant tissue cysts especially in the brain. In search of an effective treatment, guanabenz-loaded polyethylene glycol poly lactic-co-glycolic acid (PEG-PLGA) nanoparticles was evaluated against chronic experimental toxoplasmosis. For this purpose, each mouse was infected with 10 cysts of Toxoplasma gondii (ME 49 strain). Treated mice received either guanabenz alone (5 mg/kg/day) in subgroup IIa or guanabenz-loaded nanoparticles by full dose in subgroup IIb or guanabenz-loaded nanoparticles by the half dose (2.5 mg/kg/day) in subgroup IIc. Subgroup Ie was treated by pyrimethamine and sulfadiazine. The treatment started on day 25 post-infection for 19 successive days. Then Parasitological, histopathological, immunohistochemical, immunological and ultrastructural morphological studies were performed. The results showed that: subgroup IIb showed the highest statistically significant reduction in the neuroinflammation and brain tissue cysts (77%) with a significant higher efficacy in comparison with pyrimethamine and sulfadiazine and showed the highest level of IFN-γ, while the lowest level was in subgroup IIa. All group II mice showed similar changes of depression and compression of the wall of the cyst. This is marked in subgroup IIb with release of crescent shaped bradyzoite outside the cyst. PEG-PLGA nanoparticles had no toxic effect on the liver or the kidney of the mice. It could be concluded that guanabenz-loaded PEG-PLGA nanoparticles could be promising and safe for treatment of chronic toxoplasmosis.

An experimental study for evaluating the efficacy of cercarial vaccine against Schistosoma mansoni.

This study assessed the effectiveness of autoclaved cercarial vaccine (ACV) in protection against Schistosoma mansoni infection in 125 Swiss albino mice classified into two main groups: GI: a control group. GII: a test vaccinated with ACV, in a single dose of 0.1 ml of 10(4) ml ACV (G.IIa), double dose; 0.2ml (G.IIb) and two single doses 2 weeks apart (G.IIc). Four weeks later, all mice were challenged with S. mansoni cercariae and sacrificed 10 weeks post infection (P.I.). The results revealed that the vaccine in a single dose (G.IIa) induced a high level of protection against S. mansoni infection. There was a significant reduction in the mean number of adult worm (91.12%), ova/gram liver (91.87%), ova/gram intestine (89.09%) and number & size of granulomas in liver (92.92% & 43.53% respectively). Besides, ACV induced a significant increase in the level of IL-10 mRNA expression as compared to the control group.