[Liver function abnormalities in undernourished and Schistosoma mansoni-infected mice]

Antimalarial Efficacy and Safety of Senna occidentalis (L.) Link Root Extract in Plasmodium berghei-Infected BALB/c Mice

Background

Emergence of Plasmodium resistance to antimalarial drugs presents a major drawback in efforts to control malaria. To address this problem, there is an urgent and continuous need for the development of new and effective antimalarial agents. Senna occidentalis (L.) link extract has exhibited in vitro antiplasmodial activity in many pharmacological studies. To our knowledge, data on its in vivo antimalarial efficacy is still very limited. A recent study demonstrated that polar extracts from the plant roots inhibit Plasmodium berghei proliferation in a mouse model. This study further describes the efficacy and safety of a methanolic root extract of the plant as an antimalarial agent by demonstrating its effect on hematological, biochemical, and histological parameters of Plasmodium berghei-infected BALB/c mice.

Methods

Rane's test, a curative approach, was used to evaluate the antimalarial efficacy of Senna occidentalis methanolic root extract in Plasmodium berghei-infected BALB/c mice. The effect of the extract on both hematological and biochemical parameters was evaluated using automated analyzers. Kidney, liver, lung, spleen, and brain tissues were harvested from euthanized mice and examined for changes in organ architecture.

Results

This study demonstrates that methanolic root extract of Senna occidentalis significantly inhibited Plasmodium berghei parasitemia in BALB/c mice (p < 0.01). Infected mice that were treated with the extract depicted a significantly low level of total leucocytes (p < 0.01), red blood cell distribution width (p < 0.01), and a significantly high hemoglobin concentration (p < 0.001) compared to the infected animals that were administered with the vehicle only. The infected animals that were treated with the extract exhibited a significantly low level of urea, creatinine, bilirubin, and alkaline phosphatase (p < 0.05), compared to the infected animals that were given the vehicle only. The level of sodium, potassium and chloride ions, lymphocytes, granulocytes, hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration, total protein, albumin, aspartate aminotransferase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), total platelets, mean platelet volume (MPV), and platelet distribution width of the infected animals treated with the extract was not significantly different from those of the infected animals that were given the vehicle only (p > 0.05). The extract alleviated organ pathological changes in the infected mice. The extract did not induce any remarkable adverse effect on the growth, hematological, and biochemical parameters of uninfected animals (p > 0.05). In addition, administration of the extract did not alter the gross appearance and histological architecture of the organs, implying that the extract was well tolerated in mice.

Conclusions

Senna occidentalis methanolic root extract exhibited good antimalarial activity against Plasmodium berghei and may be safe in mice.

The interaction between aging and protein malnutrition modulates peritoneal macrophage function: An experimental study in male mice

Malnutrition is considered one of the most common problems in the elderly population worldwide and can significantly interfere in health evolution in these individuals, predisposing them to increased infection susceptibility. The immune response triggered by infections comprises several mechanisms, and macrophages play important roles in this response. This study aimed to evaluate mechanisms related to macrophage function in a model of protein malnutrition in the elderly. Two age groups (young: 3-5 months and elderly: 18-19 months) male C57BL/6NTac mice were subjected to protein malnutrition with a low-protein diet (2 %). The nutritional status, hemogram and number of peritoneal cells were affected by both age and nutritional status. Additionally, the spreading capacity as well as the phagocytic and fungicidal activity of peritoneal macrophages were affected by the nutritional status and age of the animal. Interestingly, the percentages of F4/80⁺/CD11b⁺ and CD86⁺ cells were reduced mostly in elderly animals, while the TLR-4⁺ population was more affected by nutritional status than by age. The production of pro-inflammatory cytokines such as TNF-α, IL-1α, and IL-6 was also influenced by nutritional status and/or by age, and malnourished animals of advanced age produced higher amounts of the anti-inflammatory cytokine IL-10. Furthermore, the phosphorylation ratio of the transcription factor NFκB (pNFκB/NFκB) was directly affected by the nutritional status, independently of age. Thus, these results allow us to conclude that aging and protein malnutrition compromise macrophage function, likely affecting their immune function, and in aged protein-malnourished animals, this impairment tends to be more pronounced.

Protein undernutrition reduces the efficacy of praziquantel in a murine model of Schistosoma mansoni infection

Background

Undernutrition and schistosomiasis are public health problems and often occur in low and middle-income countries. Protein undernutrition can alter the host-parasite environment system and aggravate the course of schistosomiasis. This study aimed to assess the impact of a low-protein diet on the efficacy of praziquantel.

Methodology/Principal findings

Thirty-day-old mice were fed with a low-protein diet, and 40 days later, they were individually infected with fifty Schistosoma mansoni cercariae. A 28-day-treatment with praziquantel at 100 mg/kg for five consecutive days followed by distilled water begins on the 36^th day post-infection. Mice were sacrificed on the 64^th day post-infection. We determined the parasitological burden, liver and intestine histomorphometry, liver injury, and immunomodulation parameters. Praziquantel treatment of infected mice fed with a standard diet (IN-PZQ) resulted in a significant reduction of worm and egg burdens and a normalization of iron and calcium levels. The therapy also improved schistosomiasis-induced hepatopathy and oxidative stress. The anti-inflammatory and immunomodulatory activities of praziquantel were also significant in these mice. When infected mice receiving the low-protein diet were treated with praziquantel (ILP-PZQ), the body weight loss and hepatomegaly were not alleviated, and the worm and liver egg burdens were significantly higher than those of IN-PZQ mice (P < 0.001). The treatment did not reduce the increased activities of ALT and γ-GGT, the high malondialdehyde concentration, and the liver granuloma volume. The iron and calcium levels were not ameliorated and differed from those of IN-PZQ mice (P < 0.001 and P < 0.05). Moreover, in these mice, praziquantel treatment did not reverse the high level of IL-5 and the low mRNA expression of CCL3/MIP-1α and CXCL-10/IP-10 induced by S. mansoni infection.

Conclusion/Significance

These results demonstrated that a low-protein diet reduced the schistosomicidal, antioxidant, anti-inflammatory, and immunomodulatory activities of praziquantel.

Almost 90% of people requiring schistosomiasis preventive chemotherapy in 2018 lived in sub-Saharan Africa. Besides, 205.3 million children under five years suffer and die of undernutrition in low- and middle-income countries. The physiopathology of schistosomiasis mansoni involves liver damage, oxidative stress, and perturbation of the immune response. These disturbances are intensified by undernutrition. Praziquantel is used to treat schistosomiasis, but its efficacy on the comorbidity of S. mansoni infection and undernutrition has not been investigated. We conducted this study to assess the effectiveness of praziquantel on S. mansoni infection in mice fed with a low-protein diet. We recorded growth retardation, hepatomegaly, and high worm and egg burdens in mice fed with a low-protein diet and treated with PZQ. Moreover, the treatment did not reverse the liver function injury, oxidative stress, high iron level, and low calcium level. The proinflammatory cytokine IL-5 was still high, and the gene expression of some macrophage-associated chemokines was reduced. Therefore, this study demonstrated that in a murine model of a low-protein diet, the efficacy of praziquantel on S. mansoni infection was reduced. It also underlines the importance of targeting protein deficiency and malnutrition in populations living in schistosomiasis endemic areas for efficient disease control.

Liver Damage Produced by Malnutrition is Improved by Dietary Supplementation in Mice: Assessment of a Supplement Based on Buriti (A Cerrado Fruit) and Dairy By-products

BACKGROUND

Malnutrition induced by dietary restriction produces several metabolic changes that affect body weight, the digestive system, and annex organs, including the liver. Malnutrition generates an inflammatory state and increases oxidative stress. The liver is one of the body vital organs, becoming necessary to analyze the impact of food supplementation on the repair of possible changes that may occur in this organ due to malnutrition.

AIMS

To evaluate the effects of a low-cost supplementation derived from Buriti and dairy byproducts on liver recovery in malnourished mice, focusing on the expression of oxidative stressrelated genes, as well as biochemical and histological parameters.

METHODS

Swiss mice were divided into six groups and submitted to two treatment phases: food restriction, for malnutrition onset; and renutrition, with mice being fed with different diets.

RESULTS

Our results indicate that dietary supplementation was successful in recovering liver damage caused by malnutrition in animal models. The new supplement has been shown to recover liver damage with similar or superior results compared to the commercial reference supplement on the market.

CONCLUSION

Our work presents a new composition of low cost food supplement based on buriti and dairy by-products, proven to be effective in the malnutrition treatment of malnutrition. The improvements were proven through the recovery of body weight, reduction of inflammation and oxidative stress.

Clinical hematological and biochemical parameters in Swiss, BALB/c, C57BL/6 and B6D2F1 Mus musculus

BACKGROUND

Animal models are widely used in scientific research in order to obtain information from a whole organism under a specific set of experimental conditions. Various lineages of mice have been used to investigate diseases and new therapeutic strategies, and, consequently, hematological and biochemical tests in these laboratory animals are essential to validate scientific studies. Our study seeks to establish reference values for hematological and biochemical parameters of four lineages of mice.

METHODS

We evaluated the hematological and biochemical profiles of 20 males and 20 females from the lineages Swiss (heterogeneous), BALB/c and C57BL/6 (isogenic), and B6D2F1 (hybrid), totaling 160 mice. Analysis were standardized using the systems pocH-100iV Diff™ for 19 hematological parameters and VITROS® 350 for 12 biochemical parameters.

RESULTS

Results are shown as means and standard deviation, grouped by lineage and genre. Comparing the values obtained in this study with the values from previous studies, some variations were detected, which could be explained by differences in methodologies or individual variability.

CONCLUSION

Thus our study shows that knowledge and disclosure of the values of physiological parameters of laboratory animals is necessary, and emphasises the importance of considering variations influenced by gender, lineage and genotype in the choice of the best experimental model.

Natural Schistosoma mansoni Infection in the Wild Reservoir Nectomys squamipes Leads to Excessive Lipid Droplet Accumulation in Hepatocytes in the Absence of Liver Functional Impairment

Schistosomiasis is a neglected tropical disease of a significant public health impact. The water rat Nectomys squamipes is one of the most important non-human hosts in the schistosomiasis mansoni transmission in Brazil, being considered a wild reservoir. Cellular mechanisms that contribute to the physiological adaptation of this rodent to the Schistosoma mansoni parasite are poorly understood. Here we identified, for the first time, that a hepatic steatosis, a condition characterized by excessive lipid accumulation with formation of lipid droplets (LDs) within hepatocytes, occurs in response to the natural S. mansoni infection of N. squamipes, captured in an endemic region. Significant increases of LD area in the hepatic tissue and LD numbers/hepatocyte, detected by quantitative histopathological and ultrastructural analyses, were paralleled by increased serum profile (total cholesterol and triglycerides) in infected compared to uninfected animals. Raman spectroscopy showed high content of polyunsaturated fatty acids (PUFAs) in the liver of both groups. MALDI-TOFF mass spectroscopy revealed an amplified pool of omega-6 PUFA arachidonic acid in the liver of infected animals. Assessment of liver functional activity by the levels of hepatic transaminases (ALT and AST) did not detect any alteration during the natural infection. In summary, this work demonstrates that the natural infection of the wild reservoir N. squamipes with S. mansoni elicits hepatic steatosis in the absence of liver functional harm and that accumulation of lipids, markedly PUFAs, coexists with low occurrence of inflammatory granulomatous processes, suggesting that lipid stores may be acting as a protective mechanism for dealing with the infection.

THE RELEVANCE OF NUTRITIONAL STATUS AND HISTOPATHOLOGICAL FINDINGS ON THE INFECTIOUS PROCESS OF BALB/C MICE INOCULATED WITH Lacazia loboi

The aim of this study was to evaluate the effects of the protein-calorie malnutrition in BALB/c isogenic mice infected with Lacazia loboi, employing nutritional and histopathological parameters. Four groups were composed: G1: inoculated with restricted diet, G2: not inoculated with restricted diet, G3: inoculated with regular diet, G4: not inoculated with regular diet. Once malnutrition had been imposed, the animals were inoculated intradermally in the footpad and after four months, were sacrificed for the excision of the footpad, liver and spleen. The infection did not exert great influence on the body weight of the mice. The weight of the liver and spleen showed reduction in the undernourished groups when compared to the nourished groups. The macroscopic lesions, viability index and total number of fungi found in the footpads of the infected mice were increased in G3 when compared to G1. Regarding the histopathological analysis of the footpad, a global cellularity increase in the composition of the granuloma was observed in G3 when compared to G1, with large numbers of macrophages and multinucleated giant cells, discrete numbers of lymphocytes were present in G3 and an increase was observed in G1. The results suggest that there is considerable interaction between Jorge Lobo's disease and nutrition.

Biochemical and histological changes in liver of Nectomys squamipes naturally infected by Schistosoma mansoni

The South American water rat Nectomys squamipes is a wild mammal reservoir of Schistosoma mansoni in Brazil. In the present study, wild rodents were collected in the field and categorized into two groups: infected and uninfected by S. mansoni. Blood was collected to analyze changes in the serum glucose level (mg/dL) and liver fragments were used to determine the hepatic glycogen content (mg of glucose/g tissue). The histological examination showed inflammatory granulomatous lesions in different phases of development in the liver of rodents naturally infected with S. mansoni, in some cases with total or partial occlusion of the vascular lumen. Early lesions were characterized by the presence of inflammatory infiltrate around morphologically intact recently deposited eggs. Despite the significance of these histological lesions, the biochemical changes differed in extent. N. squamipes naturally infected by S. mansoni showed no variation in hepatic glycogen reserves. These findings were accompanied by a significant increase in plasma glucose contents, probably as a consequence of amino acids deamination, which are degraded, resulting in the formation of intermediates used as precursors for the glucose formation, without compromising the reserves of liver glycogen. In the wild, naturally infected N. squamipes can maintain S. mansoni infections without undergoing alterations in its carbohydrate metabolism, which minimizes the deleterious effects of S. mansoni.

Hypoxia, hypoxia-inducible factor-1α and vascular endothelial growth factor in a murine model of Schistosoma mansoni infection

Schistosomiasis mansoni is a chronic parasitic disease where much of the symptomatology is attributed to granuloma formation, an immunopathological reaction against Schistosoma eggs. To more clearly understand the immunopathology of schistosomiasis, the tissue microenvironment generated by S. mansoni infected mice was investigated. Using the hypoxia marker pimonidazole, we provide immunohistochemical evidence that hypoxia occurred in inflammatory cells infiltrated around the eggs and cells surrounding granulomas in the liver, intestine, spleen and lungs of infected mice. Hypoxia-inducible factor-1α (HIF-1α) was mainly expressed in inflammatory cells surrounding the eggs and in hepatocytes surrounding cellular and fibrocellular granulomas in infected mouse liver. HIF-1α expression was also verified in granulomas in the other tissues tested (intestine, spleen and lungs). Vascular endothelial growth factor (VEGF) expression was observed in the extracellular space surrounding inflammatory cells in liver granuloma. The VEGF expression pattern verified in infected mouse liver was very similar to that observed in the other tissues tested. A strong positive correlation occurred between pimonidazole binding and HIF-1α and VEGF expression in the tissues tested, except for lung. This work is the first evidence that infection by a helminth parasite, S. mansoni, produces a hypoxic tissue microenvironment and induces HIF-1α and VEGF expression.