Effect of mushrooms on obesity in animal models: study protocol for a systematic review and meta-analysis

BACKGROUND

Obesity and its consequences are worldwide epidemic problem; therefore, studies with strategies and mechanisms that favor weight loss to improve outcomes in health are necessary. Effects of mushrooms on body weight are uncertain. The aim of this systematic review is to determine the efficacy of mushrooms in weight loss in animal preclinical models.

METHOD

This is a systematic review of preclinical studies of animal models of obesity (any type of non-aquatic mammal), which were exposed to edible and medicinal mushrooms orally in comparison with the control. The following databases will be used: MEDLINE (PubMed), Web of Science, BIOSIS, SCOPUS, and gray literature. There will be no restriction of language, date, or publication status. The primary outcome will be body weight loss. And the secondary outcomes include the total amount of food consumed by the animals, analysis of metabolic parameters, inflammatory mediators, mortality for any causes, and any adverse effect reported. A team of reviewers will select, in pairs and independently, the titles and abstracts, extract data from qualifying studies, and assess bias risk (using SYstematic Review Centre for Laboratory animal Experimentation SYRCLE's risk of bias tool and the Collaborative Approach to Meta-Analysis and Review of Animal Data from Experimental Studies (CAMARADES) checklist). The standardized mean difference (SMD) will be calculated to measure treatment effect, with 95% confidence intervals (95% CI). The heterogeneity between-study will be calculated by I2 inconsistency values and Cochran's Q statistical test, where I2 > 50% and/or p < 0.10 suggest high heterogeneity meta-analyses of random effects will be conducted as possible.

DISCUSSION

Although many experimental studies about the effects of mushrooms on obesity have already been published, there is still no consensus in the literature. This study will provide evidences of preclinical research on mushrooms and their relation to body weight loss in animal models of obesity, being non-aquatic mammals. Also, this systematic review will show the limitations and strengths of the studies available in the literature, as well as it will to encourage the financing of new studies by public health managers and governmental entities.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO (CRD42019125299).

Lentinus edodes Exposure before and after Fetus Implantation: Materno-Fetal Development in Rats with Gestational Diabetes Mellitus

Background: The presence of β-glucans and phenolic compounds in Lentinus edodes suggests this mushroom can be used as a nutritional supplement. Two gestational conditions (before and after fetus implantation) were evaluated, and Lentinus edodes exposure was performed in diabetes mellitus rat model induced by streptozotocin in pre-clinical tests. Methods: On the 20th day of pregnancy, cesarean sections were performed. Blood was collected for biochemical, hematologic parameters and oxidative stress biomarkers. Placenta and amniotic fluid were collected, and fetuses were analyzed through morphological evaluation. Results: The mushroom did not reduce the severe hyperglycemia of the mother-concept but promoted an increase in maternal insulin levels; reduced the levels of alanine aminotransferase, and aspartate aminotransferase, triglyceride and total cholesterol; protected the animals from post-implantation losses. Liver damage induced by streptozotocin was reversed in experimental groups. Conclusions: Lentinus edodes mushroom has antioxidant properties that can minimize the damage caused by gestational diabetes mellitus.

Effect of Libidibia ferrea bark and seed in maternal reproductive and biochemical outcomes and fetal anomaly in rats

BACKGROUND

Unhealthy pregnant women living in underdeveloped regions are usually treated by traditional healers, inadvertent of the potential toxic effects of plant-derivative substances. Thus, we investigated whether exposure to a hydroalcoholic extract of bark and seed of Libidibia ferrea during pregnancy results in fetotoxicity and maternal toxicity. The main constituents of both extracts were analyzed by High Performance Liquid Chromatography (HPLC).

METHODS

Pregnant rats were divided into three groups: control (C), group exposed to extract of bark (Lfb-1.0 g/kg/day), and group exposed to extract of the seed (Lfs-1.0 g/kg/day). Biochemical parameters, reproductive capacity, morphological effects in the offspring were analyzed.

RESULTS

HPLC fingerprint confirmed the presence of ellagic in both bark and seed extracts, and the absence of detectable concentrations of gallic and catechin. Fetuses exposed to L. ferrea extracts presented shorter mean lengths for head and body sections when compared to those in C and exhibited visceral and skeletal anomalies. Pregnant rats exposed to Lfs extracts show alterations in serum creatinine levels and yield amniotic fluid with abnormal biochemical composition.

CONCLUSION

Bark or seed extracts of L. ferrea do not exhibit safety level compatible to be used in the gestational period.

Laboratory animal welfare:

Reproductive and developmental toxicology has focused on the need to approach the effects of organism exposure to various drugs during pregnancy after the mid-50’s, when the thalidomide tragedy stroke humanity. In recent decades, this area of study has developed a lot due to animal testing, raising awareness on the need to improve the quality of life of such animals. Therefore, this paper aims to investigate how the science of animal welfare can improve scientific research as a whole, including the reproductive and developmental toxicology fields, by emphasizing environmental enrichment in animal facilities. To do so, we conducted an integrative literature review on several quantitative and qualitative methodological approaches that are applicable to toxicology studies. Here, we present evidence that environmental enrichment improves animal welfare and prevents or reduces the negative effects of captive housing, which must be a principle of toxicological research for ethical, legal and scientific reasons.

Acute kidney injury caused by the intraperitoneal injection of Bothrops jararaca venom in rats

We examined the ability of Bothrops jararaca venom (12.5 mg/kg) injected intraperitoneally (i.p.) to cause acute kidney injury (AKI) in rats. Blood urea and creatinine (AKI biomarkers, in g dL^-1) were elevated after 2 h in venom-treated rats (urea: from 0.41 ± 0.1 to 0.7 ± 0.03; creatinine from 46.7 ± 3.1 to 85 ± 6.7; p < 0.05; n = 3 each), with no change in circulating reduced glutathione. Venom-treated rats survived for ∼6 h, at which point platelets were reduced (×10³ µL^-1; from 763.8 ± 30.2 to 52.5 ± 18.2) whereas leukocytes and erythrocytes were slightly increased (from 4.7 ± 0.3 to 6.6 ± 0.1 × 10³ µL^-1 and from 8.38 ± 0.1 to 9.2 ± 0.09 × 10⁶ µL^-1, respectively; p < 0.05); blood protein (5.2 ± 0.4 g dL^-1) and albumin (2.7 ± 0.1 g dL^-1) were normal, whereas blood and urinary urea and creatinine were increased. All parameters returned to normal with antivenom given 2 h post-envenomation. The i.p. injection of venom caused AKI similar to that seen with other routes of administration.

Niacin prevents mitochondrial oxidative stress caused by sub-chronic exposure to methylmercury

Humans and animals can be exposed to different chemical forms of mercury (Hg) in the environment. For example, methylmercury (MeHg)-contaminated fish is part of the basic diet of the riparian population in the Brazilian Amazon Basin, which leads to high total blood and plasma Hg levels in people living therein. Hg induces toxic effects mainly through oxidative stress. Different compounds have been used to prevent the damage caused by MeHg-induced reactive oxygen species (ROS). This study aims to investigate the in vivo effects of sub-chronic exposure to low MeHg levels on the mitochondrial oxidative status and to evaluate the niacin protective effect against MeHg-induced oxidative stress. For this purpose, Male Wistar rats were divided into four groups: control group, treated with drinking water on a daily basis; group exposed to MeHg at a dose of 100 µg/kg/day; group that received niacin at a dose of 50 mg/kg/day in drinking water, with drinking water being administered by gavage; group that received niacin at a dose of 50 mg/kg/day in drinking water as well as MeHg at a dose of 100 µg/kg/day. After 12 weeks, the rats, which weighed 500-550 g, were sacrificed, and their liver mitochondria were isolated by standard differential centrifugation. Sub-chronic exposure to MeHg (100 µg/kg/day for 12 weeks) led to mitochondrial swelling (p < 0.05) and induced ROS overproduction as determined by increased DFCH oxidation (p < 0.05), increased gluthatione oxidation (p < 0.05), and reduced protein thiol content (p < 0.05). In contrast, niacin supplementation inhibited oxidative stress, which counteracted and minimized the toxic MeHg effects on mitochondria.

Characterization of the Effects of the Shiitake Culinary-Medicinal Mushroom, Lentinus edodes (Agaricomycetes), on Severe Gestational Diabetes Mellitus in Rats

This study evaluated the protective effect of Lentinus edodes in rats with streptozotocin-induced gestational diabetes mellitus (STZ-GDM) when administered orally. The rats received from the 1st to the 19th day of gestation daily doses of 100 or 200 mg/kg of lyophilized and reconstituted L. edodes; the animals in the saline control group and diabetic control group received a saline solution (DS). Gestational diabetes mellitus was induced by streptozotocin (80 mg/kg, administered intraperitoneally) on the fourth day of pregnancy; blood glucose > 180 mg/dL was considered to indicate STZ-GDM. L. edodes reduced catalase in plasma. We also observed reduced glucose in plasma, urea, triglycerides, and aspartate aminotransferase. There was a decrease in preimplantation loss when compared with the DS group. The doses of L. edodes used here had a protective effect on the preimplantation parameters in STZGDM. However, the mushroom was not able to reverse the deleterious effects caused by streptozotocin throughout the evolution of pregnancy.

Long-Term Excessive Selenium Supplementation Induces Hypertension in Rats

Selenium (Se) is an essential trace element involved in several biological pathways, naturally found in rocks, soils, and food. Even though the daily requirement of Se is achieved through a balanced diet, the use of Se supplements has been frequent. Due to the risk of toxic effects of having Se in excess, supplementation is still under debate. The aim was to evaluate the effects of long-term Se supplementation upon systolic blood pressure (SBP) and redox status of rats exposed to sodium selenite. Male Wistar rats were exposed to 2 and 6 mg/L of sodium selenite in drinking water for 85 days. SBP and body weight were evaluated weekly; oxidative stress biomarkers were measured in blood or plasma; and Se levels were assessed in blood, plasma, kidney, and liver. Se supplementation (2 and 6 mg/L) induced significant increase in the SBP in rats from the 42nd day until the end of the study. This increase on SBP was not associated with significant changes in oxidative stress biomarkers. A significant increase in Se levels was found in whole blood, kidney, and liver from both groups of rats receiving Se supplementation when compared to control. Although the exact mechanisms underlying this augment in SBP are not clear, they are potentially related to other Se biological routes besides the synthesis of selenoproteins, such as GSH-Px. Due to the negative effects upon blood pressure, precautionary measures are advised, since the selling of supplements does not require a medical prescription.

Association of Silver Nanoparticles and Curcumin Solid Dispersion: Antimicrobial and Antioxidant Properties

The last century, more precisely after 1945, was marked by major advances in the treatment of infectious diseases which promoted a decrease in mortality and morbidity. Despite these advances, currently the development of antimicrobial resistance has been growing drastically and therefore there is a pressing need to search for new compounds. Silver nanoparticles (AgNps) have been demonstrating good antimicrobial activity against different bacteria, viruses, and fungi. Curcumin (CUR) extracted from rhizomes of Curcuma longa has a variety of applications including antiinflammatory, antioxidant, and antibacterial agent. The association between silver nanoparticles and curcumin in a formulation can be a good alternative to control infectious diseases due the antimicrobial properties of both compounds. The objective of this work was to develop a formulation composed of a thermoresponsive gel-with antimicrobial and antioxidant properties due to the association of AgNps with PVP and PVA polymers. After AgNp synthesis, these were incorporated together with the previously prepared CUR/P407 (1:2) solid dispersion (SD) into a polymer dispersion of 20% P407 (thermosensitive gel). Our results showed that the association between the AgNps with CUR SD demonstrated good antioxidant activity as compared to the standard compound. Measures of MIC showed more efficacy against Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) than for Gram-positive bacteria (Staphylococcus aureus). This association enhances antimicrobial activity against E. coli and P aeruginosa and added antioxidant value in formulations.

Arsenic, cadmium, and mercury-induced hypertension: mechanisms and epidemiological findings

Arsenic (As), cadmium (Cd), and mercury (Hg) are toxic elements widely distributed in the environment. Exposure to these elements was attributed to produce several acute and chronic illnesses including hypertension. The aim of this review is to provide a summary of the most frequently proposed mechanisms underlying hypertension associated with As, Cd, and Hg exposure including: oxidative stress, impaired nitric oxide (NO) signaling, modified vascular response to neurotransmitters and disturbed vascular muscle Ca²⁺ signaling, renal damage, and interference with the renin-angiotensin system. Due to the complexity of the vascular system, a combination rather than a singular mechanism needs to be considered. In addition, epidemiological findings showing the relationship between various biomarkers of metal exposure and hypertension are described. Given the complex etiology of hypertension, further epidemiological studies evaluating the roles of confounding factors such as age, gender, and life style are still necessary.

Bacterial Nanocellulose Loaded with Bromelain: Assessment of Antimicrobial, Antioxidant and Physical-Chemical Properties

Bacterial nanocellulose (BNC) has desirable properties for wound healing such as high purity, good shape retention, and high water binding capacity. Bromelain is a protease found in pineapple tissues and has been applied in several fields, it has anti-inflammatory and anticancer properties, promotes cell apoptosis, amongst others. In this work, a BNC based device for the controlled release of bromelain was developed. BNC were submersed in sterilized bromelain solution and incubated at 25 °C under 100 rpm for 24 h. Physical-chemical properties, protein concentration, antioxidant and antimicrobial activities were measured. Results demonstrate that BNC could improve bromelain antimicrobial activity 9 times. Those findings allow concluding that bromelain is a promising molecule to be incorporated into BNC’s. The BNC’s characteristics seem to represent a new promising delivery system of the loaded biomolecule, and protected from external actions.

Distribution of arsenic and oxidative stress in mice after rice ingestion

This study evaluated the effects of rice naturally contaminated with arsenic (As) and the same As-species added as solubilized-salt on the redox state and the As distribution in male mice. The total As amount in the Brazilian polished rice used in this study was 169.81±6.12ngg^-1. Indeed, the concentrations of As species were 40.77ngg^-1 (arsenite, As³⁺), 65.71ngg^-1 (dimethylarsinic acid, DMA), 11.90ngg^-1 (monomethylarsonic acid, MMA), and 25.96ngg^-1 (arsenate, As⁵⁺). In this sense, animals were randomly divided into seven groups with six mice per group: I) control: habitual food; II) rice I: diet containing 10% of rice naturally containing As (4.08μg As³⁺/kg diet, 6.57μg DMA/kg diet, 1.19μg MMA/kg diet, and 2.60μg As⁵⁺/kg diet); III) rice II: diet containing 20% of rice naturally containing As (8.15μg As³⁺/kg diet, 13.14μg DMA/kg diet, 2.38μg MMA/kg diet, and 5.19μg As⁵⁺/kg diet); IV) rice III: diet containing 40% of rice naturally containing As (16.31μg As³⁺/kg diet, 26.28μg DMA/kg diet, 4.76μg MMA/kg diet, and 10.38μg As⁵⁺/kg diet); V) spiked feed I: diet containing As species as solubilized-salt (concentration equivalent to group II); VI) spiked feed II: diet containing As species as solubilized-salt (concentration equivalent to group III); VII) spiked feed III: diet containing As species as solubilized-salt (concentration equivalent to group IV). The time of treatment was 100days. After euthanasia, it was observed an increase in total As concentration in tissue samples of groups treated with diet containing rice naturally contaminated and diet containing As species. For instance, the highest As concentrations (higher than 330ngg^-1) was observed in the bladder of animals belonging to Rice II and III and spiked feed III groups. Furthermore, it was verified the highest As concentrations in bladder > hair > lung > kidney > liver > blood. We also observed the presence of DMA and As⁵⁺ in liver and kidneys. Regarding oxidative stress biomarkers, we observed significant reduction of Glutathione (GSH) concentration in blood of animals belonging to groups IV, V, VI and VII. Besides, the antioxidant enzymes activities, Glutathione Peroxidase (GSH-Px), Catalase (CAT) and superoxide dismutase (SOD), increased significantly in blood of animals belonging to group VII. On the other hand, it was not observed differences in nitric oxide (NO) levels among all the groups used in this study and the control group. Thus, we conclude that some minor effects were found in mice exposed to the diet containing the highest amount of rice naturally contaminated with As species. These findings contribute to evaluate the safety of human dietary consumption.

Safety and efficacy of hydroxyapatite scaffold in the prevention of jaw osteonecrosis in vivo

Two scaffolds of chitosan/sodium alginate/hydroxyapatite (Ch/NaAlg/Hap) 1:1:0.2 and 1:1:0.6 were evaluated in the prevention of bisphosphonate-induced jaw osteonecrosis. Two groups of rats (n = 24, according to the euthanasia time: 15 or 30 days after the last Zoledronic acid (ZA) administration) were subdivided in four subgroups (n = 6): I - Control (saline + teeth extraction); II - ZA 0.6 mg/kg + teeth extraction; III - ZA + teeth extraction + scaffold 1:1:0.2; IV - ZA + teeth extraction + scaffold 1:1:0.6. Jaws were evaluated histologically and blood was evaluated for hematological and biochemical parameters. Histopathology showed significant osteonecrosis in AZ group. The scaffold's implantation, despite the inflammatory process, were able to prevent the osteonecrosis. In the 15-day euthanasia group, an increase in red blood cells and platelets was observed in the subgroup II. Hemoglobin and hematocrit decreased in subgroup IV compared to II. Hepatic transaminases and creatinine concentration increased significantly in subgroup II. Calcium concentration increased in subgroup IV compared to II. In the 30-day euthanasia group, no differences among the groups were observed for any parameter. Scaffolds proved to be efficient and safe to liver and kidney function. Some hematological parameters were altered by the scaffold, but returned to normal concentrations over time. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1799-1808, 2018.

Assessment of the Safety of the Shiitake Culinary-Medicinal Mushroom, Lentinus edodes (Agaricomycetes), in Rats: Biochemical, Hematological, and Antioxidative Parameters

Lentinus edodes is an edible mushroom studied for use, or as an adjunct, in the prevention of illnesses such as hypertension, hypercholesterolemia, diabetes, and cancer. Despite the functional properties of L. edodes, the doses commonly reported in experimental studies are much higher than those actually consumed. Thus, we aimed to establish the optimum intake levels of L. edodes in vivo. Four groups of male Wistar rats received dry and powdered L. edodes reconstituted in water for 30 days: control (water only), L. edodes 100 mg/kg, L. edodes 400 mg/kg, and L. edodes 800 mg/kg. Biochemical and hematological parameters were assessed using commercial kits. Antioxidant parameters were quantified spectrophotometrically. Neither cholesterol, triglycerides, glucose, nor transaminase activity was different among any of the L. edodes concentrations. However, fructosamine concentrations were significantly decreased in groups consuming L. edodes at 100 or 400 mg/kg. A significant decrease in hemoglobin concentration was found in the 400 and 800 mg/kg/day L. edodes groups, and leukopenia occurred in rats that consumed L. edodes 800 mg/kg/day compared with the control group. L. edodes at 100 and 400 mg/kg increased amounts of reduced glutathione compared with the control group. L. edodes was effective as an antioxidant at 100 and 400 mg/kg, but at 400 and 800 mg/kg some disturbances were observed, such as reductions in hemoglobin and leukocytes. In summary, this study has potential benefits for scientific development because the safe daily intake of L. edodes (at 100 mg/kg) is, to our knowledge, reported for the first time in a preclinical study.

Clinical comparison of salicylic acid peel and LED-Laser phototherapy for the treatment of Acne vulgaris in teenagers

Acne vulgaris treatments usually cause sensitivity, teratogenicity and bacterial resistance. Investigations of other therapeutic techniques, such as phototherapy, are highly relevant. Thus, we compared the effectiveness of two Acne vulgaris treatments in adolescents: peeling with salicylic acid (SA) and phototherapy. Teens were randomly divided into: group I, treatment with SA peels (10%) and group II, treatment with phototherapy (blue LED and red laser lights). Photographs were taken before and after ten sessions of each treatment, carried out weekly, and compared. To compare the differences between the treatments, the Student t-test was used. P values < 0.05 were considered significant. Both techniques are effective therapies for the treatment of acne in teenagers since the number of comedones, papules and pustules decreased significantly at the end of the session. However, when the two treatments were compared, phototherapy showed a significant difference in reducing the number of pustules. The combined use of red and blue lights due to their anti-inflammatory and wound-healing properties is a more efficient alternative for treating Acne vulgaris in relation to SA and proves more reliable and without side effects, improving the adolescents' skin health.

Protective effects of niacin against methylmercury-induced genotoxicity and alterations in antioxidant status in rats

This study investigates the potential beneficial effects of niacin (NA; vitamin B3) supplementation in rats chronically exposed to methylmercury (MeHg). Animals were randomly assigned to one of 4 groups (n = 6): Group I, control, received distilled water by gavage; Group II, received MeHg (100 µg/kg/d) by gavage; Group III, received NA (50 mg/kg/d) in drinking water; Group IV, received MeHg (100 µg/kg/d) by gavage + NA (50 mg/kg/d) in drinking water. Biochemical parameters levels of glucose, triglycerides, total cholesterol and fractions, and enzyme activities aspartate transaminase (AST) and alanine transaminase (ALT) were determined. Further, oxidative stress markers activity of glutathione peroxidase (GPx) and catalase (CAT) activity, as well as levels of reduced glutathione (GSH), malondialdehyde (MDA), and nitric oxide, were examined, and the comet assay was performed, using blood/plasma. Hg levels were measured in blood, brain, and kidneys of animals. Our results demonstrated that NA reduced adverse effects produced by MeHg. The mechanism underlying these effects appears to be related to the intrinsic antioxidant potential of NA. Considering the beneficial effects attributed to NA following MeHg exposure and that fish are the main source of both NA and MeHg, future studies need to evaluate the potential counteractive effect of NA against the adverse consequences of MeHg exposure in fish-eating populations.

Effects of genetic polymorphisms on antioxidant status and concentrations of the metals in the blood of riverside Amazonian communities co-exposed to Hg and Pb

There have been reports of genetic effects affecting the metabolism of Hg and Pb individually, and thus modulating their toxicities. However, there is still a knowledge gap with respect to how genetics may influence the toxicities of these toxic metals during a co-exposure scenario. This present study is therefore aimed at investigating the effects of polymorphisms in genes (GSTM1, GSTT1, GSTP1, GCLM, GCLC, GPx1, ALAD, VDR and MDR1) that have been implicated in Hg and Pb metabolisms affects the kinetics of these metals, as well as various blood antioxidant status parameters: MDA and GSH, and the activities of CAT, GPx and ALAD among populations that have been co-exposed to both Hg and Pb. Study subjects (207 men; 188 women) were from an Amazonian population in Brazil, exposed to Hg and Pb from diet. The blood levels of Hg and Pb were determined by ICP-MS while genotyping were performed by PCR assays. The median values of Hg and Pb in blood were 39.8µg/L and 11.0µg/dL, respectively. GSTM1, ALAD and VDR polymorphisms influenced Hg in blood (β=0.17; 0.37 and 0.17; respectively, p<0.050) while variations on GCLM, GSTT1 and MDR1 (TT) modulated the concentrations of Pb among the subjects (β=-0.14; 0.13 and -0.22; re-spectively, p<0.050). GSTT1 and GCLM polymorphisms also are associated to changes of MDA concentrations. Persons with null GSTM1 genotype had higher activity of the antioxidant enzyme CAT than carries of the allele. Individuals with deletion of both GSTM1 and GSTT1 had a decreased expression of GPx compared to those that expressed at least, one of the enzymes. ALAD 1/2 subjects had lower ALAD activity than individuals with the non-variant genotype. Our findings give further support that polymorphisms related to Hg and Pb metabolism may modulate Hg and Pb body burden and, consequently metals-induced toxicity.

Deficiency of macro- and micronutrients induced by Lentinula edodes

Mushroom Lentinula edodes has been widely studied therapeutically. However, there is no data regarding its daily intake level safety. Since L. edodes has many active compounds known to bind to metals, we evaluated macro and micronutrients in liver and kidney of healthy rats after subchronic exposure to L. edodes. Rats were divided into four groups, receiving water and L. edodes at 100, 400 and 800 mg/kg/day. The treatment lasted 30 days. Essential elements (Zn, Cu, Mg, Fe, Mn, Se, Co, Mo, and Li) were analyzed in an inductively coupled plasma mass spectrometer. Our results demonstrated a significant decrease in Cu, Fe, Mn and Co levels in liver of rats receiving L. edodes at the highest doses. In kidney, Mn, Mo and Li concentrations significantly dropped in the groups exposed to the highest doses. In this way, an important point is revealed concerning the food safety from L. edodes, once its chronic and high consumption could contribute to macro and micronutrients deficiency. Additionally, we speculate that the daily use of L. edodes could be unsuccessful for patients in mineral therapy besides being able to be unsafe for individuals with some propensity to mineral deficiency.

Safety assessment of the royal sun mushroom, Agaricus brasiliensis (higher Basidiomycetes) intake during rat pregnancy

In this study, we investigated the reproductive capacity of pregnant rats exposed to daily orally administered powder-dehydrated reconstituted of Agaricus brasiliensis (=Agaricus blazei sensu Murrill), the fetal organogenesis, and the development of the pups. Pregnant rats were exposed for the entire gestational period to water (control) and A. brasiliensis at 300 or 600 mg/kg/day. Fertility and body weight of dams were monitored. Pups were monitored for body weight, offspring vitality, morphology, and physical and neurobehavioral development. An increase in sternebrae agenesis was observed at the 600 mg/kg/day dose of A. brasiliensis, while incomplete ossification of sternebrae was seen even at a 300 mg/kg/day dose. In conclusion, this study is the first to demonstrate the impact of maternal exposure to A. brasiliensis on the fetal organogenesis and development of offspring in a rat model. The 600 mg/kg/day dose showed some negative effects, and low toxicity was observed at the 300 mg/kg/day dose.

A systematic study of the disposition and metabolism of mercury species in mice after exposure to low levels of thimerosal (ethylmercury)

Thimerosal (TM) is an ethylmercury (etHg)-containing preservative used in some vaccines despite very limited knowledge on the kinetics and direct interaction/effects in mammals׳ tissues after exposure. Thus, this study aimed to evaluate the kinetics of Hg species in mice in a time course analysis after intramuscular injection of TM, by estimating Hg half-lives in blood and tissues. Mice were exposed to one single intramuscular dose of 20 µg of Hg as TM. Blood, brain, heart, kidney and liver were collected at 0.5 hour (h), 1 h, 8 h, 16 h, 144 h, 720 h and 1980 h after TM exposure (n=4). Hg species in animal tissues were identified and quantified by speciation analysis via liquid chromatography hyphenated with inductively coupled mass spectrometry (LC-ICP-MS). It was found that the transport of etHg from muscle to tissues and its conversion to inorganic Hg (inoHg) occur rapidly. Moreover, the conversion extent is modulated in part by the partitioning between EtHg in plasma and in whole blood, since etHg is rapidly converted in red cells but not in a plasma compartment. Furthermore, the dealkylation mechanism in red cells appears to be mediated by the Fenton reaction (hydroxyl radical formation). Interestingly, after 0.5 h of TM exposure, the highest levels of both etHg and inoHg were found in kidneys (accounting for more than 70% of the total Hg in the animal body), whereas the brain contributed least to the Hg body burden (accounts for <1.0% of total body Hg). Thirty days after TM exposure, most Hg had been excreted while the liver presented the majority of the remaining Hg. Estimated half-lives (in days) were 8.8 for blood, 10.7 for brain, 7.8 for heart, 7.7 for liver and 45.2 for kidney. Taken together, our findings demonstrated that TM (etHg) kinetics more closely approximates Hg(2+) than methylmercury (meHg) while the kidney must be considered a potential target for etHg toxicity.