الفهرس 
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Abstract
Toxoplasmosis is a global disease caused by T. gondii infection which mostly occurs through the oral transmission route. It affects a wide range of warm-blooded mammalian hosts, including humans. Congenital toxoplasmosis is caused by maternal–fetal transmission essentially during the acute stage. It rarely occurs throughout chronic maternal infection during gestation as a result of a recrudescence. It may produce various pathological manifestations among offspring ranging from meningoencephalitis to retinochoroiditis and inflammatory bowel disease starting three months up to 20 years later.
Till now, the treatment of toxoplasmosis has met great challenges particularly during pregnancy. A safe and effective drug against toxoplasmosis in pregnancy would be considered a great success. Spiramycin, a macrolide antibiotic, is used safely during pregnancy, it is less toxic than other drugs and it is able to attain high concentrations in the placenta. However, little is known about its entry to fetal circulation and it demonstrated poor penetration across the BBB. In this context, the search for new strategies to overcome and improve the drawbacks of spiramycin treatment is warranted. Nanomedicine can provide an applicable solution to this problem. CNPs, the nontoxic cationic polysaccharide crustacean extract product, possesses good capacity for increasing the drugs penetration and delivery across the tissue barriers. Therefore, this study aimed to evaluate the efficacy of SLCNPs and Aluvia for the treatment of congenital toxoplasmosis in Swiss albino mice.
In a trial to achieve the aim of this work, after performing pilot experiments, the study was conducted on 60 pregnant Swiss albino mice; each mouse was infected subcutaneously on day 15 (3rd gestation period) of pregnancy with 30 tachyzoites of the virulent T. gondii RH strain. Infected mice were then subdivided into control and experimental groups.
Mice of the experimental group received spiramycin, SLCNPs and Aluvia. Nanoparticles zeta potential, SEM, loading efficiency, drug entrapment, drug release and storage stability were studied.
The results of nanoparticles revealed outright perfection regarding all measured parameters.
The efficacy of spiramycin, SLCNPs and Aluvia against toxoplasmosis was evaluated in terms of fertility parameters, number of offspring, pups weight, congenital anomalies, histopathological changes of brain and parasite load in liver, spleen and brain impression smears. qRT-PCR was applied to assess the liver parasite load.
According to the outcomes of the fertility parameters, most stillborn pups were delivered from the infected non-treated control and some treated subgroups. All drugs succeeded in increasing the number of live births and remarkably decreased stillbirths compared to infected control. The best results were achieved by SLCNPs as it showed no abortion and 100% partum rate. Spiramycin and Aluvia treated subgroups revealed the same partum and abortion rates of 90% and 10% respectively.
Concerning the offspring numbers, spiramycin and SLCNPs produced a slight increase in the total offspring counts. The offspring counts of all treated mice showed no statistically significant difference compared to infected non-treated mothers.
Considering the mean pups weight, SLCNPs ranked first followed by the Aluvia treated mice. Spiramycin showed the lowest effect on the improvement of the pups’ weight.
Congenital anomalies were observed in infected non-treated control and in some treated mice. They showed abnormal jaws, abnormal body axis, hydrocephaly, club foot, distended abdomen, paddle-shaped foot, ophthalmic anomalies, and weak musculature. They were cannibalized by their mothers shortly after birth once they discovered the congenital anomalies through their tactile visual and olfactory senses. Unfortunately, all the mothers died within 7 days after delivery.
Concerning the offspring brain’s histopathological study, a remarkable improvement of pathologic changes was found in tissue sections of offspring brains obtained from SLCNPs and Aluvia treated mice. Normal neuroglial cells with no evidence of inflammation and no apoptotic cells were detected indicating successful crossing of BBB and mothers’ placentas. Spiramycin alone showed lower improvement due to its poor crossing of BBB.
Based on the qRT-PCR, T. gondii tachyzoites were quantified in 25 mg pooled livers of infected control and each experimental group. All used drugs reduced the parasite load. The remarkable decrease of the tachyzoite counts in SLCNPs treated mice (81.7%) was statistically significant compared to spiramycin (50.4%) and Aluvia (53.8%) subgroups.
The parasite load in impression smears of the liver, spleen and brain were counted. All drugs succeeded in decreasing the parasite load with different reduction rates. Concerning the liver impression smears of mice receiving spiramycin and SLCNPs, tachyzoite counts reduction (42.2% and 44.4% respectively) was statistically significant as compared to control. In spleen impression smears, the best reduction rate of tachyzoites was achieved using SLCNPs (39.5%). However, this reduction was statistically insignificant. The brain impression smears of mice treated with spiramycin, SLCNPs and Aluvia showed significant reduction in tachyzoite counts (22.2%, 55.5% and 51.8% respectively) as compared to the control. The present results revealed that the best drug that succeeded in tachyzoite decrease was the SLCNPs, and it successfully crossed the placenta and the offspring BBB. Aluvia showed promising results, it may be optimized further for the treatment of congenital toxoplasmosis.
To the best of our knowledge, this is the first work undertaken to study the treatment of congenital toxoplasmosis in the third gestation period in infected pregnant mice.