Trypanosoma evansi impacts on embryonic neural progenitor cell functions.

Trypanosoma evansi appears to have a significant tropism for brain tissue in its chronic and acute phases. The most common symptoms of this brain infection are motor incoordination, meningoencephalitis, demyelination, and anemia. There have only been few studies of the effects of T. evansi infection on neuronal differentiation and brain plasticity. Here, we investigated the impact of the congenital T. evansi infection on brain development in mice. We collected telencephalon-derived neural progenitor cells (NPCs) from T. evansi uninfected and infected mice, and cultivated them into neurospheres. We found that T. evansi significantly decreased the number of cells during development of neurospheres. Analysis of neurosphere differentiation revealed that T. evansi infection significantly increased neural migration. We also observed that T. evansi promoted expression of glial fibrillary acidic protein (GFAP) in infected cells. These data suggest that congenital T. evansi infection may affect embryonic brain development.

Effects of resveratrol on the differentiation fate of neural progenitor cells of mouse embryos infected with Trypanosoma cruzi.

Chagas disease (CD) affecting about 7 million people is caused by the flagellate protozoan Trypanosoma cruzi. The central nervous system (CNS) is an important site for T. cruzi persistence in the host during the chronic phase of infection, because the protozoan may pass the blood-brain barrier and may cause motor and cognitive neuronal damage. Thinking about avoiding or minimizing these negative effects, it is hypothesized that resveratrol (RSV), a component with several medicinal properties has beneficial effects on the CNS. The objective of this study was to investigate, whether T. cruzi infection interferes with neurogenesis and gliogenesis of embryos of infected mice females, and whether RSV would be able to avoid or minimize these changes caused by CD. RSV is a polyphenol found in grapes and widely studied for its neuroprotective and antioxidant properties. In addition, we investigated the role caused by the parasite during congenital infection and CNS development. Embryos and their brains were PCR-positive for T. cruzi. For this study, NPCs obtained from telencephalon of infected and uninfected embryos and were cultured in presence of resveratrol for forming neurospheres. The results demonstrated that the congenital transmission of T. cruzi influences CNS formation and neural fate, decreasing the number of neuroespheres and causing an elongation in the phases of the cell cycle. In addition, the parasite promoted an increase in neugliogenesis. Resveratrol was neuroprotective and prevented negative effects of the infection. Thus, we suggest the use of resveratrol as a therapeutic target for the treatment of neuroinflammation or as neuroprotective agent during Chagas disease, as it improves gliogenesis and restores neural migration.

Cordycepin (3'-deoxyadenosine) and pentostatin (deoxycoformycin) against Trypanosoma cruzi.

The aim of this study was to evaluate in vitro the efficacy of cordycepin and pentostatin (alone or combined) against Trypanosoma cruzi, as well as the therapeutic efficiency of protocols of cordycepin and pentostatin combinations in mice experimentally infected with T. cruzi. In vitro, the cordycepin (3'-deoxyadenosine) and pentostatin (deoxycoformycin) exerted potent trypanocidal effect against T. cruzi (Colombian strain), similarly to benznidazole, which is the reference drug. For epimastigotes, the lethal dose of cordycepin capable of killing 50% (LD50) and 20% (LD20) of the parasites was 0.072 and 0.031 mg/mL, respectively and for trypomastigotes was 0.047 and 0.015 mg/mL, respectively. The combined use of cordycepin and pentostatin resulted in a LD50 and LD20 for epimastigotes of 0.068 and 0.027 mg/mL, respectively, as well as 0.056 and 0.018 mg/mL for trypomastigotes, respectively. In vivo, the combined use of cordycepin and pentostatin did not show the expected curative effect, however it was able to control the parasitema in the peak period. In summary, the combination of cordycepin and pentostatin showed no curative effect in mice infected by T. cruzi, despite the in vitro reduction of epimastigotes and trypomastigotes.

Ecto-enzymes activities in splenic lymphocytes of mice experimentally infected by Trypanosoma cruzi and treated with specific avian immunoglobulins: an attempt to improve the immune response.

The aim of this study was to evaluate the therapeutic efficacy of specific avian polyclonal antibodies (IgY) against Trypanosoma cruzi and their interaction with ecto-enzymes of the purinergic system (NTPDase and adenosine deaminase (ADA) activities) in splenic lymphocytes. For this, mice were divided into six groups: three non-infected (A, B, and C) and three infected (D, E, and F). The groups A and D were composed by negative and positive controls, respectively; while the groups B and E were treated prophylactically with IgY (50 mg/kg), and the groups C and F were treated therapeutically with IgY (50 mg/kg). Treatment with IgY reduced parasitemia on day 6 post-infection (PI) compared to the infected control group, but it was similar on day 8 PI. Moreover, infected and treated animals (the groups E and F) did not show neither amastigotes in the cardiac tissue nor cardiac lesions when compared to the positive control group (the group D). The E-NTPDase (ATP and ADP as substrate) and ADA activities in splenic lymphocytes increased significantly in the positive control group (the group D) compared to the negative control group (the group A). The therapeutic treatment of IgY (the group F) was able to prevent the increase of E-NTPDase and E-ADA activities compared to the positive control group (the group D), but this finding was not observed in animals that received the prophylactic treatment (the group E). The therapeutic treatment of IgY may be considered an interesting approach to improve the immune response of mice experimentally infected by T. cruzi.

Nucleotide and nucleoside involvement in immunomodulation in experimental Chagas disease.

The aim of this study was to evaluate whether Trypanosma cruzi infections cause alterations in the levels of seric purines, which could contribute to host immunomodulation. Twelve mice were divided into two groups identified as control (uninfected) and infected (T. cruzi) groups. The influence of the disease on seric purine levels was verified on day 20 post-infection (PI) by HPLC. Infected mice had circulating trypomastigotes during the experiment, as well as amastigote forms in the heart associated with inflammatory infiltrates. Increases on adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine (ADO), inosine (INO), and uric acid (URIC) levels were observed in the infected animals, while the adenosine monophosphate (AMP) and xanthine (XAN) levels were reduced compared with mice of the control group, indicating a possible impairment on the purinergic system, and consequently, on the immune system during the clinical course of the disease. In summary, the T. cruzi infection alters the seric purine levels, and consequently, modulates the immune system.

Treatment with 3'-deoxyadenosine and deoxycoformycin in mice infected by Trypanosoma cruzi and its side effect on purinergic enzymes.

The aim of this study was to evaluate the efficacy of 3'-deoxyadenosine and deoxycoformycin combination in the treatment of mice infected by T. cruzi, as well as to verify the influence of the treatment on purinergic enzymes. Heart and serum samples were collected from 60 mice (30 infected and 30 uninfected) at day 12 post-infection. To verify treatment efficacy, parasitemia was monitored, and the treatment with 3'-deoxy adenosine and deoxycoformycin combination was able to reduce it, but had no curative effect on mice. Seric activities of NTPDase (ATP and ADP substrate) and ADA were increased significantly in untreated mice infected by T. cruzi compared to the negative control, as well as mice treated with 3'-deoxyadenosine and deoxycoformycin (alone or combined) modulated the activity of NTPDase (ATP and ADP substrate), preventing them from increasing in infected animals (activity similar to healthy animals). Treatment with deoxycoformycin alone and associated with 3'-deoxyadenosine modulated the activity of ADA preventing them from increasing in infected animals. However, seric activities of ADA in mice treated with 3'-deoxyadenosine (cordycepin) alone does not modify the ADA activity compared with infected and non-treated mice. However, the 5'-nucleotidase activity decreased significantly in infected untreated animals and the same occurred in infected and treated animals with deoxycoformycin and 3'-deoxyadenosine. However, treatment with deoxycoformycin associated with 3'-deoxyadenosine preventing them from decreasing the 5'-nucleotidase activity. Therefore, we conclude that the treatments did not have curative success for mice infected by T. cruzi. However, the treatments were able to modulate the purinergic enzymes during the infection by T. cruzi, which may contribute to reduce the inflammatory damage in heart.

Treatment with tucumã oil (Astrocaryum vulgare) for diabetic mice prevents changes in seric enzymes of the purinergic system: Improvement of immune system.

The aim of this study was to evaluate the enzymatic activity of the purinergic system in sera samples from alloxan-induced diabetic mice treated with tucumã oil (Astrocaryum vulgare). For this, the mice were divided into four groups (n=6): control/water (the group CW); control/tucumã oil (the group CT); diabetic/water (the group DW), and diabetic/tucumã oil (the group DT) treated for 14days with 5.0mLkg-1 via oral gavage. On day 14 post-treatment, mice were submitted to euthanasia and blood samples were collected by cardiac puncture. Tucumã oil treatment significantly decreased (p<0.05) blood glucose levels in the group DT compared to the group DW. These results demonstrated an increase (p<0.05) in NTPDase (adenosine triphosphate (ATP substrate) or adenosine diphosphate (ADP substrate)), 5'-nucleotidase (AMP substrate) and adenosine deaminase (ADA; adenosine substrate) activities in serum from the group DW compared to the group CW. Tucumã oil treatment prevented these alterations in the group DT compared to the group DW, and restored these parameters near to the group CW. In summary, the treatment with tucumã oil was able to modulate the alterations caused by hyperglycemia probably by the presence of carotenoids compounds, maintaining normal levels of ATP, ADP, AMP and adenosine, molecules that could exhibit anti-inflammatory properties, depending on their concentration. Thus, the tucumã oil is a promising natural compound with protective action against diabetes and its side effects, such as changes in the purinergic system, improving the immune system.

Avian antibodies (IgY) against Trypanosoma cruzi: Purification and characterization studies.

Trypanosoma cruzi is a flagellated protozoan belonging to the Trypanosomatidae family, the etiologic agent of Chagas disease. Currently, there is neither a licensed vaccine nor effective treatment, characterizing an unmet clinical need. The IgY refers to the egg yolk immunoglobulin (Y=yolk) and its production and use are subjects of many studies due to the diversity of its diagnostic and therapeutic applications. Several researchers have shown that the use of specific IgY may prevent and/or control infectious and parasitic diseases. Based on these evidences, the aim of this study was to immunize chickens with trypomastigotes of T. cruzi in order to produce highly effective and pure antibodies (IgY), as well as extract, characterize, quantify, and verify cytotoxic effects of IgY anti-T. cruzi. After the induction of IgY production by chickens, the eggs were collected and the IgY was extracted by method of precipitation of polyethylene glycol 6000. The IgY anti-T. cruzi characterization was performed using polyacrylamide gel electrophoresis (SDS-PAGE), western-blot and enzyme-linked immunosorbent assay (ELISA). Moreover, the cytotoxic or proliferative effects of IgY anti-T. cruzi was verified by MTT assay. The concentration of IgY in yolk was 8.41±1.47mg/mL. The characterization of IgY reveled bands of stained peptides with molecular weight between 75 and 50kDa and 37 and 25kDa. In the ELISA test was observed that there was antigen-antibody reaction throughout the sample period. The concentrations of 1, 5 and 10mg/mL of IgY anti-T. cruzi presented no cytotoxic of proliferative effects in mononuclear and VERO cells in vitro. The results indicated that T. cruzi is able to generate a high production of specific immunoglobulins in chickens, it did not cause damage to the cell membrane and no proliferative effect.

The use of tucumã oil (Astrocaryum vulgare) in alloxan-induced diabetic mice: effects on behavior, oxidant/antioxidant status, and enzymes involved in brain neurotransmission.

The aim of this study was to investigate the effects of tucumã oil (Astrocaryum vulgare) on memory, enzymatic activities of sodium-potassium pump (Na+, K+-ATPase) and acetylcholinesterase (AChE) in the brain of alloxan-induced diabetic mice. The animals were divided into four groups (n = 6 each): the group A (non-diabetic/water), the group B (non-diabetic/tucumã oil), the group C (diabetic/water), and the group D (diabetic/tucumã oil) treated 14 days with 5.0 mL kg-1 via oral gavage. Untreated diabetic mice (the group C) showed memory deficit, increased levels of thiobarbituric acid reactive species (TBARS) and protein carbonylation (PC), and decreased (p < 0.05) catalase (CAT), superoxide dismutase (SOD), and the Na+, K+-ATPase activities, while acetylcholinesterase (AChE) activity showed a significant increase (p < 0.05) compared to non-diabetic mice (the group A). Tucumã oil prevented these alterations in diabetic mice treated with tucumã oil (the group D) compared to diabetic mice (the group C). Our findings suggest that tucumã oil can modulate cholinergic neurotransmission resting membrane potential of neurons by modulating enzymatic antioxidant defenses. In conclusion, the present data showed that treatment with tucumã oil is beneficial to diabetic mice, demonstrating that this oil can modulate cholinergic neurotransmission and consequently improve or avoid memory deficits.

Solving the challenge of the blood-brain barrier to treat infections caused by Trypanosoma evansi: evaluation of nerolidol-loaded nanospheres in mice.

Despite significant advances in therapies against Trypanosoma evansi, its effective elimination from the central nervous system (CNS) remains a difficult task. The incapacity of trypanocidal drugs to cross the blood-brain barrier (BBB) after systemic administrations makes the brain the main refuge area for T. evansi. Nanotechnology is showing great potential to improve drug efficacy, such as nerolidol-loaded nanospheres (N-NS). Thus, the aim of this study was to investigate whether the treatment with N-NS was able to cross the BBB and to eliminate T. evansi from the CNS. High-performance liquid chromatography revealed that N-NS can cross the BBB of T. evansi-infected mice, while free nerolidol (F-N) neither the trypanocidal drug diminazene aceturate (D.A.) were not detected in the brain tissue. Polymerase chain reaction revealed that 100% of the animals treated with N-NS were negatives for T. evansi in the brain tissue, while all infected animals treated with F-N or D.A. were positives. Thus, we concluded that nanotechnology improves the therapeutic efficacy of nerolidol, and enables the transport of its active principle through the BBB. In summary, N-NS treatment can eliminate the parasite from the CNS, and possesses potential to treat infected animals.

ß-caryophyllene reduces atherogenic index and coronary risk index in hypercholesterolemic rats: The involvement of cardiac oxidative damage.

Hypercholesterolemia and cardiac oxidative damage have been implicated in the pathophysiology of atherosclerosis. In earlier studies, treatment using natural phytocannabinoid ß-caryophyllene caused a hypolipemic effect, as well as ameliorated hepatic oxidative damage. In this regard, the present study aimed to investigate whether ß-caryophyllene treatment was able to protect the cardiac tissue against hypercholesterolemic atherosclerosis, and to investigate the involvement of antioxidant mechanisms in this effect using a model of hypercholesterolemia induced by Triton WR-1339. The hypercholesterolemic animals exhibited a significant increase in the cholesterol (TC), triglycerides (TG) and free fatty acids (FFA) contents in cardiac tissue, as well as showed significant increase on atherogenic index (AI) and coronary risk index (CRI). Moreover, cardiac levels of reactive oxygen species (ROS) and thiobarbituric acid reactive substances (TBARS) were increased in hypercholesterolemic animals, while the glutathione reduced (GSH) levels and glutathione peroxidase (GPx) activity were decreased. ß-caryophyllene treatment reduced the cardiac lipid content, as well as decreased the AI and CRI. Moreover, the treatment was able to improve the antioxidant/oxidant status in heart tissue of hypercholesterolemic animals. In summary, ß-caryophyllene possesses antioxidant properties, preventing lipidic oxidative damage and ameliorating the GPx activity, an important enzyme linked to the prevention of atherosclerosis. Thus, this compound can be used as an attempt to prevent or reduce atherosclerosis in hypercholesterolemic rats.

Antihyperglycemic, antioxidant activities of tucumã oil (Astrocaryum vulgare) in alloxan-induced diabetic mice, and identification of fatty acid profile by gas chromatograph: New natural source to treat hyperglycemia.

The aim of the study was to investigate the effect of the oral administration of tucumã oil (Astrocaryum vulgare) on glucose and insulin levels, oxidative status, and pancreatic genotoxic parameters of alloxan-induced diabetic mice. The animals were divided into four groups (n = 6 each): control/water; control/tucumã oil; diabetic/water; diabetic/tucumã oil treated for 14 days with 5.0 mL kg-1 via oral gavage. Gas chromatograph characterization demonstrated that oleic/elaidic fatty acid is the most abundant component present in this oil, followed by palmitic and stearic fatty acids. Our results demonstrated an increase (p < 0.05) in water and food intake, blood glucose, thiobarbituric acid reactive species (TBARS) levels, damage index, and frequency of damage; conversely body weight, insulin levels, catalase (CAT) and superoxide dismutase (SOD) activities, and cell viability were decreased in the diabetic/water group compared to the control/water group. The treatment with tucumã oil prevented these alterations in the diabetic/tucumã oil group compared to the diabetic/water group, and restored these parameters near to the control/water group. In summary, our findings demonstrated that treatment with tucumã oil causes a hypoglycemic effect improving insulin levels and antioxidant/oxidant status, and has a protector effect against pancreatic damage induced by oxidative stress in alloxan-induced diabetic mice.

Purinergic ecto-enzymes participate in the thromboregulation in acute in mice infection by Trypanosoma cruzi.

Coagulation disorders have been described in Chagas disease with thrombocytopenia as an important event. Several mechanisms may be related to this pathogenesis, such as enzymes of the purinergic system, purine, and receptors involved in the regulation and modulation of physiological events related to hemostasis. Therefore, the aim of this study was to evaluate the activities of E-NTPDase, E-5'nucleotidase, and ecto-adenosine deaminase (E-ADA) in platelets of mice experimentally infected by Trypanosoma cruzi. Twelve female mice were used, divided into two groups (n = 6): uninfected and infected. Mice of infected group were intraperitoneally inoculated with 104 trypomastigotes of T. cruzi (strain Y). On day 12 post-infection (PI), blood samples were collected for quantitation and separation of platelets. A significant reduction in the number of platelets of infected mice (P < 0.05) was observed. The activities of E-NTPDase (ATP and ADP substrates), E-5'nucleotidase, and E-ADA in platelets increased significantly (P < 0.05) in mice infected by T. cruzi compared with uninfected animals. A negative correlation (P < 0.01)was observed between the number of platelets and ATP hydrolysis (r = -0.64), and ADP hydrolysis (r = -0.69) by E-NTPDase. Therefore, there is a response from the purinergic system activating ecto-enzymes in platelets of mice T. cruzi infected, as a compensatory effect of thrombocytopenia.

Purinergic enzymatic activities in lymphocytes and cardiomyocytes of mice acutely infected by Trypanosoma cruzi modulating the inflammatory responses.

The aim of this study was to evaluate the activity of purinergic enzymes in lymphocytes and cardiac tissue of mice experimentally infected by Trypanosoma cruzi. Twelve female mice were used, divided into two groups (n = 6): uninfected and infected. On day 12 post-infection (PI), the animals were anesthetized and after euthanized, and samples were collected for analyses. Infected mice showed reduction in erythrocyte counts, hematocrit and hemoglobin concentration, as well as reduced number of total leukocytes in consequence of neutrophilia (P < 0.01). The number of monocytes increased in infected mice (P < 0.001), however the number of lymphocytes and eosinophils did not differ between groups (P > 0.05). The E-NTPDase (ATP and ADP substrate) and E-ADA activities in lymphocytes increased significantly in mice infected by T. cruzi (P < 0.01). In the heart, multiple pseudocysts containing amastigotes within cardiomyocytes were observed, as well as focally extensive severe necrosis associated with diffuse moderate to severe inflammatory infiltrate of lymphocytes. Although, the NTPDase activity (ATP and ADP substrate) in the cardiac homogenate did not differ between groups, a reduction on 5'-nucleotidase activity (P < 0.001) and an increase in the ADA activity in infected animals (P < 0.05) were observed. Thus, animals infected by T. cruzi experienced the disease, i.e., showed anemia, leucopenia, and heart lesions. Associated with this, purinergic enzymes showed altered activities, which might be related to the modulation of the inflammatory response.

Nerolidol-loaded nanospheres prevent hepatic oxidative stress of mice infected by Trypanosoma evansi.

The aim of this study was to evaluate the effect of nerolidol free (N-F) and nerolidol-loaded in nanospheres (N-NS) on the hepatic antioxidant/oxidant status of mice experimentally infected by Trypanosoma evansi. In the liver it was measured: reactive oxygen species (ROS), thiobarbituric reactive acid substances (TBARS) and non-protein thiols (NPSH), catalase (CAT), superoxide dismutase (SOD) and glutathione-S-transferase (GST) and performed histopathological examination. In addition, seric levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were measured. Liver samples from mice infected by T. evansi showed increased (P < 0·05) ROS, TBARS, AST and ALT levels and SOD activity, and decreased NPSH levels and CAT activity (P < 0·05) compared with uninfected animals. N-NS treatment prevented (P < 0·05) ROS and TBARS increase, and increased NPSH levels, and ameliorate CAT and SOD activities on liver of infected mice. Moreover, N-NS treatment reduced (P < 0·05) AST and ALT levels, and prevented histopathological changes caused by the parasite. N-NS protected the liver from the oxidative stress caused by T. evansi, which might be due to its antioxidant properties. Nerolidol might be considered a promising therapeutic agent against oxidative stress, and nanotechnology is an encouraging approach to be explored.

Nerolidol-loaded nanospheres prevent behavioral impairment via ameliorating Na+, K+-ATPase and AChE activities as well as reducing oxidative stress in the brain of Trypanosoma evansi-infected mice.

The aim of this study was to investigate the effect of nerolidol-loaded nanospheres (N-NS) on the treatment of memory impairment caused by Trypanosoma evansi in mice, as well as oxidative stress, and Na+, K+-ATPase and acetylcholinesterase (AChE) activities in brain tissue. Animals were submitted to behavioral tasks (inhibitory avoidance task and open-field test) 4 days postinfection (PI). Reactive oxygen species (ROS) and thiobarbituric acid-reactive substance (TBARS) levels and catalase (CAT), superoxide dismutase (SOD), Na+, K+-ATPase and AChE activities were measured on the fifth-day PI. T. evansi-infected mice showed memory deficit, increased ROS and TBARS levels and SOD and AChE activities, and decreased CAT and Na+, K+-ATPase activities compared to uninfected mice. N-NS prevented memory impairment and oxidative stress parameters (except SOD activity), while free nerolidol (N-F) restored only CAT activity. Also, N-NS treatment was able to prevent alterations in Na+, K+-ATPase and AChE activities caused by T. evansi infection. A significantly negative correlation was observed between memory and ROS production (p < 0.001; r = -0.941), as well as between memory and AChE activity (p < 0.05; r = -0.774). On the contrary, a significantly positive correlation between memory and Na+, K+-ATPase activity was observed (p < 0.01; r = 0.844). In conclusion, N-NS was able to reverse memory impairment and to prevent increased ROS and TBARS levels due to amelioration of Na+, K+-ATPase and AChE activities and to activation of the antioxidant enzymes, respectively. These results suggest that N-NS treatment may be a useful strategy to treat memory dysfunction and oxidative stress caused by T. evansi infection.

Hypolipidemic effect of ß-caryophyllene to treat hyperlipidemic rats.

The aim of this study was to evaluate the effect of ß-caryophyllene on hypercholesterolemia using a model of hyperlipidemia induced by Triton WR-1339 in rats, as well as its possible effect on hepatic antioxidant enzymes. Thus, total cholesterol, triglycerides, low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol were measured in serum, while reactive oxygen species (ROS), thiobarbituric acid reactive substances (TBARS), hepatic 3-hydroxy-3-methylglutayl coenzyme A (HMG-CoA) reductase, superoxide dismutase (SOD), and catalase (CAT) activities were measured in the hepatic tissue. In addition, seric concentrations of ß-caryophyllene were measured to perform correlation studies. Serum samples from hypercholesterolemic rats show higher (p < 0.05) levels of total cholesterol, triglycerides, and LDL cholesterol, and lower (p < 0.05) levels of HDL cholesterol compared to non-hypercholesterolemic rats. ß-Caryophyllene treatment reduced (p < 0.05) the levels of total cholesterol, triglycerides and LDL cholesterol, similar to the reference drug simvastatin. However, HDL cholesterol levels did not increase with the treatment. ß-Caryophyllene treatment was able to inhibit the HMG-CoA reductase activity, as well as to prevent the increase on ROS and TBARS levels, and ameliorate the antioxidant system. In summary, our findings demonstrated that ß-caryophyllene has hypolipidemic effect via inhibition of the hepatic HMG-CoA reductase, like the standard drug simvastatin, and this inhibition suggests a possible mechanism of hypolipidemic action. Thus, our results indicate that ß-caryophyllene can be used to treat dyslipidemic diseases because it exerts a similar effect as the reference drug, protecting the liver against lipid damage and improving the hepatic antioxidant defense system.

Achyrocline satureioides essential oil-loaded in nanocapsules reduces cytotoxic damage in liver of rats infected by Trypanosoma evansi.

The aim of this study was to evaluate whether the treatment with Achyrocline satureioides essential oil-loaded in nanocapsules (AS-NC) is able to protect the hepatic tissue against cytotoxic damage caused by Trypanosoma evansi. Thus, the rats were divided into four groups (n = 6 per group): uninfected/saline, uninfected/AS-NC, infected/saline, and infected/AS-NC. At day 4 post-infection (PI), the animals were euthanized and liver and sera samples were collected to perform the hepatic cell viability assay, and to determine seric levels of reactive oxygen species (ROS) and nitric oxide metabolites (NOx). Cell viability decreased (p < 0.05) in the infected/saline group compared to uninfected/saline group, while the treatment with AS-NC avoided this alteration in infected rats. Seric ROS and NOx levels increased (p < 0.05) in the infected/saline group compared to uninfected/saline group, while the treatment with AS-NC avoided this effect on ROS levels of infected rats. In summary, the treatment with AS-NC was able to protect the liver tissue against the cytotoxic effect caused by the parasite by avoiding exacerbated production of ROS.

A nanotechnology based new approach for Trypanosoma evansi chemotherapy: In vitro and vivo trypanocidal effect of (-)-α-bisabolol.

The aim of this study was to evaluate the in vitro and in vivo susceptibility of Trypanosoma evansi to α-Bisabolol and solid lipid nanoparticles containing α-Bisabolol (SLN-B). In vitro, a trypanocidal effect of α-Bisabolol and SLN-B was observed when used at 0.5, 1 and 2% concentrations, i.e., the concentrations of 1 and 2% showed a faster trypanocidal effect when compared to chemotherapy (diminazene aceturate - D.A.). T. evansi infected mice were treated with α-Bisabolol and SLN-B at a dose of 1.0 mL kg-1 during seven days via oral gavage. In vivo, treatment with SLN-B, D.A. and D.A. associated with SLN-B were able to increase (p < 0.05) the pre-patent period and longevity when compared to positive control (infected and untreated animals), but showed no curative efficacy. T. evansi infected mice treated with D.A. associate with SLN-B, where a curative efficacy of 50% was found, a much better result when D. A and SLN-B were used alone (16.66%). In summary, the association with D. A + SLN-B can be used as an alternative to improve the therapeutic effectiveness of D.A., and for treatment of infected animals with T. evansi. Also, the nanotechnology associated with natural products arises an important alternative for the improve the trypanocidal action.

Melaleuca alternifolia anthelmintic activity in gerbils experimentally infected by Haemonchus contortus.

Gastrointestinal parasites are one of the biggest health problems faced in sheep, mainly due to their pathogenicity and resistance to drugs used to control these parasites. Thus, the following study aimed to assess the anthelmintic efficacy of Melaleuca alternifolia against Haemonchus contortus in gerbils (Meriones unguiculatus) experimentally infected. Three treatments were tested: M. alternifolia essential oil, popularly known as tea tree oil (TTO), a solid lipid nanocarrier made with essential oil of Melaleuca (nanoTTO), and terpinen-4-ol (terp-4-ol). In vivo studies were performed by determining the mean worm burden of H. contortus in gerbils TTO (0.75 mL/kg); nanoTTO (0.5 mL/kg) and terp-4-ol (0.5 mL l/kg) were able to reduce 46.36%; 48.64%, and 43.18% worm burden, respectively. H. contortus increased alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, as demonstrated by liver injury. It was found that the TTO, nanoTTO, and terp-4-ol were not toxic to liver and kidneys since hepatic and renal functions were not affected. Moreover, terp-4-ol was able to prevent increased levels of seric AST and ALT in infected animals, indicating a hepatoprotective effect. Thus, our results indicate that TTO, nanoTTO, and terp-4-ol are safe and efficient against H. contortus infection in gerbils, and possibly the terp-4-ol may be considered the compound present in the Melaleuca alternifolia responsible for parasitic action against H. contortus.