Chronic Murine Toxoplasmosis Research Articles

Could metformin modulate the outcome of chronic murine toxoplasmosis?

Toxoplasmosis is a pervasive parasitic infection possessing a chief impact on both public health and veterinary medicine. Unfortunately, the commercially-available anti-Toxoplasma agents have either serious side effects or diminished efficiency, specifically on the Toxoplasma tissue cysts. In the present study, metformin (The first-line treatment for type 2 diabetes mellitus) was investigated for the first time against chronic cerebral toxoplasmosis in mice model experimentally-infected with ME49 strain versus spiramycin. Two metformin regimens were applied; starting one week before the infection and four weeks PI. Parasitological, ultrastructural, histopathological, immunohistochemical, immunological, and biochemical assessments were performed. The anti-parasitic effect of metformin was granted by the statistically-significant reduction in tissue-cyst burden in both treatment regimens. This was accompanied by markedly-mutilated ultrastructure and profound amelioration of the cerebral histopathology with remarkable decline in the brain CD4+ and CD8+ T cell count. Besides, diminution of anti-Toxoplasma IgG and brain GSH levels was evident. Ultimately, the present findings highlighted the powerful promising therapeutic role of metformin in the management of chronic toxoplasmosis on a basis of anti-parasitic, anti-inflammatory, and anti-oxidant possessions.

Therapeutic potential of coconut and ginger oils in chronic murine toxoplasmosis

Therapeutic potential of coconut and ginger oils in chronic murine toxoplasmosis

Anti-inflammatory and Anti-oxidative Effects of Some Medicinal Herbs on Chronic Murine Toxoplasmosis: A Histopathological and Immunohistochemical Study

Anti-inflammatory and Anti-oxidative Effects of Some Medicinal Herbs on Chronic Murine Toxoplasmosis: A Histopathological and Immunohistochemical Study

Protective efficacy of Toxoplasma gondii infected cells-derived exosomes against chronic murine toxoplasmosis

Exosomes were isolated from T. gondii infected human hepatoblastoma cells using the exosome isolation kit and characterized by electron microscopy and Western blotting. Exosomes adsorbed to alum adjuvant were evaluated as a potential immunizing agent against murine chronic toxoplasmosis compared to excretory secretory antigens (ESA)-alum. Mice were immunized at days 1, 15 and 29. The levels of IgG, IFN-γ, IL-4 and IL-10, CD4+ and CD8+ T cells were determined using sandwich enzyme-linked immunosorbent assay (sandwich ELISA) at days 14, 28 and 56 of the experiment. Then mice were infected orally with 10 cysts of T. gondii. The protective efficacy of the antigens were evaluated by counting the brain cysts and measuring the aforementioned humoral and cellular parameters 60 days post infection. The results showed that alum increased the protective efficacy of the exosomes. Immunization with exosome-alum induced both humoral and mixed Th1/Th2 cellular immune responses. Exosome-alum gave higher levels of the humoral and cellular parameters, compared to ESA-alum. After challenge infection, exosome-alum significantly reduced the brain cyst burden by 75 % while ESA-alum gave 42 % reduction and evoked higher humoral and cellular immune responses. Therefore, the possibility of using T. gondii infected cells-derived exosome-alum as a vaccine is a new perspective in toxoplasmosis.

The effect of Nigella sativa oil- and wheat germ oil-loaded metal organic frameworks on chronic murine toxoplasmosis

Treatment of chronic toxoplasmosis is challenging as the available drugs are effective only in the acute stage. Therefore, the current study aimed to investigate Nigella sativa oil (NSO) and wheat germ oil (WGO) loaded on copper-benzene tricarboxylic acid metal organic framework (Cu-BTC MOF) for treating chronic toxoplasmosis in a murine model. Eighty mice were divided into 8 groups (G); uninfected untreated negative control (GI), infected untreated positive control (GII), infected and treated with: Spiramycin (GIII), Spiramycin@Cu-BTC (GIV), Cu-BTC (GV), WGO@Cu-BTC (GVI), NSO@Cu-BTC (GVII) and combined WGO+NSO@Cu-BTC (GVIII). The infected groups were orally inoculated with 10 Toxoplasma gondii Me49 strain cysts/mouse. All drugs were orally administered for 14 consecutive days starting 8 weeks post-infection (wpi). The therapeutic efficacy was evaluated by parasitological (survival rate of mice and brain cyst burden) and histopathological (brain, liver, kidney, eye) parameters. At the end of 2-weeks therapy, the highest therapeutic outcome was achieved with GVII and GVIII exhibiting 100% survival, 64.3% and 51.4% reduction of brain cysts, and an apparent amendment of pathological insults. In the next place was GVI with 90% survival, 49.5% reduction of cysts and marked amelioration of pathological lesions. Meanwhile, GIII and GIV showed 80% survival, 42.4% and 41.8% reduction of cysts as well as minimal to moderate alleviation of tissue damage. The lowest effect was obtained with GV resulting in 70% survival and 24.4% reduction of cysts. The current results support the assertion that the new metal-based nanocomposites can be promising remedies of chronic toxoplasmosis particularly if conjugated with natural herbal extracts as NSO and WGO.

The delayed death-causing nature of Rosmarinus officinalis leaf extracts and their mixture within experimental chronic toxoplasmosis: Therapeutic and prophylactic implications

BackgroundThe restricted effect, significant toxicity, and emerging resistance of anti-toxoplasmosis synthetic agents impose the search for alternatives. The current research aimed to evaluate the prophylactic and therapeutic efficacy of Rosmarinus officinalis extracts and their mixtures against chronic murine toxoplasmosis and to clarify the phenomenon of delayed death. MethodsThis research included two experimental designs, the first to test the preventive and curative efficacy of the extracts and the second to assess delayed death in mice infected with the ME49 strain of Toxoplasma gondii. The essential oils of the plant were analyzed by gas chromatography/mass spectrometry. Results: Treatment with a mixture of rosemary extracts displayed reduction rates of 81% for T. gondii cyst burden and 23% for cyst viability. The reinfected group with the pretreated cysts reported 93.4% reduction in cyst burden and 95.4% in cyst viability. Moreover, 90% reduction of the infectivity rate was obtained. The therapeutic efficacy of this mixture was superior to its valuable prophylactic effect. Histopathological examination of liver and brain tissue exhibited marked improvement. Both extracts possess free radical scavenging and antioxidant activities evidenced by high expression of iNOS stain. Our results were signified by low BAG-1 gene expression and massive mutilation of T. gondii cyst in the targeted group using scanning electron microscopy. Analysis of R. officinalis revealed the presence of isobornylformate as a novel ingredient. ConclusionsR. officinalis displays a therapeutic rather than prophylactic potential, indicating the emergence of an effective safe alternative therapy.

Immunological, histopathological, and ultrastructural evidence of steroid-induced reactivation of chronic murine toxoplasmosis

ABSTRACT We developed a model of steroid-induced reactivation of chronic murine toxoplasmosis to mirror similar effects of steroids or other immunosuppressants in infected humans. Immunological, histopathological, and ultrastructural parameters were reported. Prior to steroid administration, mice were infected with 10 cysts of the Me49 strain of Toxoplasma gondii. Mice were treated with dexamethasone (DXM, 2.5 mg/kg/day in drinking water), alone or combined with Solu-Cortef (SOLU, 50 mg/kg by subcutaneous injection 3 times a week) for 7 weeks or left untreated as control. Histopathological changes and ultrastructural effects of steroids on the course of chronic toxoplasmosis were recorded. By electron microscopy, the brains of infected combined treated mice showed an increase in number of tachyzoites and bradyzoites, degeneration, and necrosis of neural cells and hydropic degeneration besides the observed rupture of toxoplasma cysts releasing free tachyzoites in brain tissue. DXM+SOLU-combined treatment also significantly increased mortality, mean brain cyst count as compared to infected untreated mice (P = .01 and). Moreover, 3/12 (25%) treated animals developed clinical signs of toxoplasmic encephalitis. This simple model of drug-induced reactivation of chronic toxoplasmosis permits investigation of host-parasite interaction and may be used for the evaluation of chemotherapeutics in immunocompromised infected patients.

Hepatic Metabolomics Investigation in Acute and Chronic Murine Toxoplasmosis.

Toxoplasma gondii poses a great threat to human health, with no approved vaccine available for the treatment of T. gondii infection. T. gondii infections are not limited to the brain, and may also affect other organs especially the liver. Identification of host liver molecules or pathways involved in T. gondii replication process may lead to the discovery of novel anti-T. gondii targets. Here, we analyzed the metabolic profile of the liver of mice on 11 and 30 days postinfection (dpi) with type II T. gondii Pru strain. Global metabolomics using liquid chromatography-tandem mass spectrometry (LC-MS/MS) identified 389 significant metabolites from acutely infected mice; and 368 from chronically infected mice, when compared with control mice. Multivariate statistical analysis revealed distinct metabolic signatures from acutely infected, chronically infected and control mice. Infection influenced several metabolic processes, in particular those for lipids and amino acids. Metabolic pathways, such as steroid hormone biosynthesis, primary bile acid biosynthesis, bile secretion, and biosynthesis of unsaturated fatty acids were perturbed during the whole infection process, particularly during the acute stage of infection. The present results provide insight into hepatic metabolic changes that occur in BALB/c mice during acute and chronic T. gondii infection.

Chronic murine toxoplasmosis is defined by subtle changes in the neuronal connectivity

Recent studies correlate chronic Toxoplasma gondii (T. gondii) infection with behavioral changes in rodents; additionally, seropositivity in humans is reported to be associated with behavioral and neuropsychiatric diseases. In this study we investigated whether the described behavioral changes in a murine model of chronic toxoplasmosis are associated with changes in synaptic plasticity and brain neuronal circuitry. In mice chronically infected with T. gondii, magnetic resonance imaging (MRI) data analysis displayed the presence of heterogeneous lesions scattered throughout all brain areas. However, a higher density of lesions was observed within specific regions such as the somatosensory cortex (SSC). Further histopathological examination of these brain areas indicated the presence of activated resident glia and recruited immune cells accompanied by limited alterations of neuronal viability. In vivo diffusion-tensor MRI analysis of neuronal fiber density within the infected regions revealed connectivity abnormalities in the SSC. Altered fiber density was confirmed by morphological analysis of individual, pyramidal and granule neurons, showing a reduction in dendritic arbor and spine density within the SSC, as well as in the hippocampus. Evaluation of synapse efficacy revealed diminished levels of two key synaptic proteins, PSD95 and synaptophysin, within the same brain areas, indicating deficits in functionality of the synaptic neurotransmission in infected mice. Our results demonstrate that persistent T. gondii infection in a murine model results in synaptic deficits within brain structures leading to disturbances in the morphology of noninfected neurons and modified brain connectivity, suggesting a potential explanation for the behavioral and neuropsychiatric alterations.

Simultaneous HPLC Determination of Metronidazole and Spiramycin in Plasma and Brain of Mouse

Treatments fail to eliminate Toxoplasma gondii due to low drug brain penetration. Spiramycin is an Mrp2, Pglycoprotein substrate, active in acute and chronic murine toxoplasmosis. Metronidazole is a CYP3A4 inhibitor and Pglycoprotein substrate. We developed a simple HPLC method to analyze spiramycin and metronidazole simultaneously. Male Balb/c mice were randomly selected in three groups and were dosed orally either 500 mg/kg metronidazole (group 1, n=4) or 400 mg/kg spiramycin (group 2, n=4) or coadministered 500 mg/kg metronidazole 30 min prior to 400 mg/kg spiramycin (group 3, n=4). Mice were euthanized 2 hours after spiramycin administration. Metronidazole and spiramycin brain and plasma concentrations were measured by HPLC using a Phenomenex® C-18 (150x3.8 mm, 5 μm) column and acetonitrile-phosphate buffer (pH 2.5) gradient elution (20/80 to 30/70 in 3 min) at 1 mL/min flow, 29°C and 232 nm. The method was linear (0.25-50.0 μg/mL), the LLOQ was 0.25 μg/mL, intra- and interday variability, precision and accuracy were within 15%. Recoveries were above 75% and there was no matrix interference. Metronidazole eluted at 3 min and spiramycin at 5 min. Spiramycin did not affect plasma metronidazole concentration (6.93±0.48 μg/mL in combination vs. alone 7.65±0.55 μg/mL) or brain (2.96±0.60 μg/g after coadministration vs. control, 4.02±0.78 μg/g). Metronidazole did not change spiramycin plasma concentration (coadministration: 3.94±1.30 μg/mL, control: 3.71±0.94 μg/mL). However, spiramycin brain concentration increased 2-fold after metronidazole coadministration from 2.44±0.33 μg/g to 4.83±1.25 μg/g (P < 0.05). Metronidazole increased spiramycin brain uptake, probably due to P-glycoprotein inhibition, which may improve toxoplasmosis encephalitis treatments.

Effect of immunosuppressive drug regimens on acute and chronic murine toxoplasmosis.

To evaluate the potential risk of dissemination or reactivation of toxoplasmosis following the administration of immunosuppressive therapy we examined the effect of corticoids, azathioprine, and cyclosporine given alone or in combination on the course of murine acute and chronic toxoplasmic infection. Swiss Webster mice were infected perorally with a high-level inoculum of cysts of the C strain of Toxoplasma gondii. The evolution of the kinetics of parasite loads in the blood, brain, and lungs of infected and immunosuppressed mice was then sequentially followed. In mice with orally acquired infections initiated 2 days after the beginning of drug treatment, immunosuppression led to the persistence of parasites, especially in the lungs, which was most marked in mice treated with azathioprine and/or cortisol acetate. Administration of immunosuppressive therapy in mice previously infected with T. gondii resulted in a brief resurgence of parasite loads when treatment was started early after infection. Finally, under our experimental conditions we found that the immunosuppressive drugs that were given altered the natural course of infection with a prolonged persistence of parasites in the lungs but did not significantly affect parasite loads in the brain or lead to disseminated infection with detectable parasitemia.

Uterine atrophy in chronic murine toxoplasmosis due to ovarian dysfunction.

Uterine atrophy is a conspicuous finding in Nya:NYLAR female mice chronically infected with Toxoplasma gondii. Administration of 17B-estradiol to infected mice induced a vigorous uterotropic response, i.e., an increase in uterine weight, in endometrial hypertrophy and proliferation, and in the activity of three estrogen-regulated uterine enzymes. These findings rule out a parasite-induced refractoriness of the uterus to estrogen and point to ovarian dysfunction (hypogonadism) as the immediate cause of the uterine atrophy.

Chronic murine toxoplasmosis: clinicopathologic characterization of a progressive wasting syndrome

Nya:NYLAR albino mice infected with Toxoplasma gondii gradually developed a chronic and progressive wasting syndrome characterized by facial and body alopecia, corneal opacities, necrotic lesions of ears and tail, signs of neurologic disease and death within six to eight months after infection. Haematologic changes included a transient normochromic, normocytic anaemia, and persistent lymphopenia and neutrophilia. Changes in serum proteins were manifested by hypoalbuminaemia and pronounced hypergammaglobulinaemia. Serum thyroxine concentrations fell sharply during the first month of infection, then gradually returned to control concentrations. Gross changes included loss of body weight, hepatosplenomegaly, ovarian and uterine atrophy, and a marked involution of the thymus. The predominant histopathologic change in the brain was a mononuclear cell vasculitis, particularly affecting the hippocampus and the choroid plexus, ependyma, and periventricular areas of the lateral and third ventricles. These preliminary observations indicate that mice can serve as a practical animal model of great potential for study of the pathogenesis of chronic toxoplasmosis.