Safety of Exposure to 0.2 T and 4 Hz Rotating Magnetic Field: A Ten-Month Study on C57BL/6 Mice.

Amidst the burgeoning interest in rotating magnetic fields (RMF) within biological research, there remains a notable gap in the scientific evidence concerning the long-term safety of RMF. Thus, this study aimed to investigate the safety of protracted exposure to a 0.2 T, 4 Hz RMF over 10 months in mice. Two-month-old female C57BL/6 mice were randomly allocated to either the RMF group (exposed to 0.2 T, 4 Hz real RMF) or the SHAM group (exposed to 0 T, 4 Hz sham RMF). Throughout the experiment, the murine weekly body weights were recorded, and their behavioral traits were assessed via open field tests. In the final month, a comprehensive evaluation of the murine overall health was conducted, encompassing analyses of blood parameters, histomorphological examination of major organs, and skeletal assessments using X-ray and micro-CT imaging. The murine immune system and lipid metabolism were evaluated through immunochip analysis and metabolomics. Notably, no discernible adverse effects with RMF exposure were observed. Murine body weight, locomotor behavior, organ histomorphology, and skeletal health remained unaffected by RMF. Blood analysis revealed subtle changes in hormone and lipid levels between the SHAM and RMF groups, yet these differences did not reach statistical significance. Moreover, RMF led to elevated serum interleukin-28 (IL-28) levels, albeit within the normal range, and modest alterations in serum lipid metabolites. Conclusively, mice exposed to the 0.2 T, 4 Hz RMF for 10 months displayed no significant signs of chronic toxicity, indicating its potential clinical application as a physical therapy.

Comprehensive Toxicological Assessment of Halobenzoquinones in Drinking Water at Environmentally Relevant Concentration.

Halobenzoquinones (HBQs), an emerging unregulated category of disinfection byproduct (DBP) in drinking water, have aroused an increasing concern over their potential health risks. However, the chronic toxicity of HBQs at environmentally relevant concentrations remains largely unknown. Here, the occurrence and concentrations of 13 HBQs in drinking water from a northern megacity in China were examined using ultrahigh performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry (UHPLC-MS/MS). Four HBQs, including 2,6-dichloro-1,4-benzoquinone (2,6-DCBQ), 2,6-dibromo-1,4-benzoquinone (2,6-DBBQ), 2,3,6-trichloro-1,4-benzoquinone (TriCBQ), and 2,5-dibromo-1,4-benzoquinone (2,5-DBBQ), were detected beyond 50% occurrence frequency and at median concentrations from 4 to 50 ng/L. The chronic toxicity of these four HBQs to normal human colon and liver cells (FHC and THLE-2) was investigated at these concentrations. After 90 days of exposure, 2,5-DBBQ and 2,6-DCBQ induced the highest levels of oxidative stress and deoxyribonucleic acid (DNA) damage in colon and liver cells, respectively. Moreover, 2,5-DBBQ and 2,6-DCBQ were also found to induce epithelial-mesenchymal transition (EMT) in normal human liver cells via the extracellular signal regulated kinase (ERK) signaling pathway. Importantly, heating to 100 °C (boiling) was found to efficiently reduce the levels of these four HBQs in drinking water. These results suggested that environmentally relevant concentrations of HBQs could induce cytotoxicity and genotoxicity in normal human cells, and boiling is a highly efficient way of detoxification for HBQs.

Acute and chronic toxicity in Sprague-Dawley rats of orally-administered total lignans from Arctii Fructus, a potential therapeutic drug for diabetes.

Arctii Fructus is the dried ripe fruit of Arctium lappa L. (family Asteraceae) and is in the Chinese pharmacopoeia. Previous research showed that the total lignans from Arctii Fructus (TLAF) have pharmacological activities related to diabetes. This study evaluated the acute and chronic (26 weeks) toxicities associated with oral daily administration of TLAF in Sprague-Dawley (SD) rats. An acute-toxicity test showed that TLAF caused 10% mortality at 3,000 mg/kg × 2 (6-h interval), with toxic symptoms, such as dyspnea and tonic convulsions, indicating potential neurotoxicity. A chronic-toxicity study showed no mortality after administration. The no observed adverse-effect level was 1,800 mg/kg (approximately 54 times higher than the human clinical dose) for 26 weeks of TLAF oral administration in SD rats, with toxicity signs of excessive oral and nasal secretions and moist circumferential hair that recovered after TLAF discontinuation. In the toxicokinetic study, the two main components of TLAF, arctigenin plasma level was positively correlated with dose and tended to accumulate after multiple doses. At 1,800 mg/kg, arctiin plasma level increased and tended to accumulate after multiple doses. These results indicated that TLFA has relatively low toxicity and the potential for clinical treatment of diabetes.

Chronic aquatic toxicity assessment of diverse chemicals on Daphnia magna using QSAR and chemical read-across.

We have modeled here chronic Daphnia toxicity taking pNOEC (negative logarithm of no observed effect concentration in mM) and pEC50 (negative logarithm of half-maximal effective concentration in mM) as endpoints using QSAR and chemical read-across approaches. The QSAR models were developed by strictly obeying the OECD guidelines and were found to be reliable, predictive, accurate, and robust. From the selected features in the developed models, we have found that an increase in lipophilicity and saturation, the presence of electrophilic or electronegative or heavy atoms, the presence of sulphur, amine, and their related functionality, an increase in mean atomic polarizability, and higher number of (thio-) carbamates (aromatic) groups are responsible for chronic toxicity. Therefore, this information might be useful for the development of environmentally friendly and safer chemicals and data-gap filling as well as reducing the use of identified toxic chemicals which have chronic toxic effects on aquatic ecosystems. Approved classes of drugs from DrugBank databases and diverse groups of chemicals from the Chemical and Product Categories (CPDat) database were also assessed through the developed models.

Bacillus subtilis ZB423: 90-Day repeat dose oral (gavage) toxicity study in Wistar rats.

The novel genetically modified probiotic Bacillus subtilis ZB423 was assessed in a 90-day repeated-dose oral toxicity study adhering to Good Laboratory Practice (GLP) and Organization for Economic Cooperation and Development (OECD) guidelines. Spray-dried spores at a concentration of 1.1E12 CFU/g were administered at doses of 130, 260, and 519 mg/kg body weight/day correlating to 1.43 × 1011, 2.86 × 1011, and 5.71 × 1011 CFU/kg/day, respectively, by oral gavage to Wistar rats for a period of 90 consecutive days. Results showed no toxicologically relevant findings for B. subtilis ZB423 from measured parameters. The no observed adverse effect level (NOAEL) of B. subtilis ZB423 is 519 mg/kg body weight/day corresponding to 5.71 × 1011 CFU/kg/day for lyophilized B. subtilis ZB423 spores under the test conditions employed.

Prediction of chronic toxicity of pharmaceuticals in Daphnia magna by combining ortholog prediction, pharmacological effects, and quantitative structure-activity relationship.

To develop a method for predicting chronic toxicity of pharmaceuticals in Daphnia, we investigated the feasibility of combining the presence of drug-target orthologs in Daphnia magna, classification based on pharmacological effects, and ecotoxicity quantitative structure-activity relationship (QSAR) prediction. We established datasets on the chronic toxicity of pharmaceuticals in Daphnia, including information on therapeutic categories, target proteins, and the presence or absence of drug-target orthologs in D. magna, using literature and databases. Chronic toxicity was predicted using ecotoxicity prediction QSAR (Ecological Structure Activity Relationship and Kashinhou Tool for Ecotoxicity), and the differences between the predicted and measured values and the presence or absence of drug-target orthologs were examined. For pharmaceuticals without drug-target orthologs in D. magna or without expected specific actions, the ecotoxicity prediction QSAR analysis yielded acceptable predictions of the chronic toxicity of pharmaceuticals. In addition, a workflow model to assess the chronic toxicity of pharmaceuticals in Daphnia was proposed based on these evaluations and verified using an additional dataset. The addition of biological aspects such as drug-target orthologs and pharmacological effects would support the use of QSARs for predicting the chronic toxicity of pharmaceuticals in Daphnia.

The effects of two short-chain perfluoroalkyl carboxylic acids (PFCAs) on northern leopard frog (Rana pipiens) tadpole development.

Short-chain perfluoroalkyl carboxylic acids (PFCAs) have been detected in the environment globally. The presence and persistence of these compounds in the environment may lead to chronic wildlife exposure. We used northern leopard frog (Rana pipiens) tadpoles to investigate the chronic toxicity and the bioconcentration of two short-chain PFCAs, perfluorobutanoic acid (PFBA) and perfluorohexanoic acid (PFHxA). We exposed Gosner stage 25 tadpoles to PFBA and PFHxA (as individual chemicals) at nominal concentrations of 0.1, 1, 10, 100, and 1000 µg/L for 43-46 days. Tadpoles exposed to 0.1 to 100 µg/L of PFBA and PFHxA had significantly higher mean snout-to-vent lengths, mean masses, and scaled mass indexes than control tadpoles. These results indicate that exposure to short-chain PFCAs influences tadpole growth. Further investigation into the mechanism(s) causing the observed changes in tadpole growth is warranted. We observed a significantly higher proportion of males in the PFBA 1 µg/L treatment group, however further histological analyses are required to confirm visual sex identification before making concrete conclusions on the effects of PFCAs on amphibian sex ratios. PFBA concentrations in tissues were higher than PFHxA concentrations; a pattern that contrasts with previously published studies using fish, suggesting potential differences between taxa in PFBA and PFHxA bioconcentration. Bioconcentration factors were <10 L/kg wet weight, indicating low bioconcentration potential in tadpoles. Our results suggest that PFBA and PFHxA may have effects at environmentally-relevant concentrations (0.1-10 µg/L) and further investigation is required before these compounds can be deemed a "safe" alternative to their long-chain counterparts.

Safety assessment of crude aqueous methanol extract of Annona senegalensis stem bark: acute and sub-chronic toxicity studies.

Annona senegalensis Pers., (wild custard apple), is a shrub used traditionally to treat respiratory and skin diseases. Previous studies have demonstrated its anti-malaria, anti-snake envenomation and anti-cancer activities. However, its toxicological profile remains limited, particularly in male and female animals. This study aims to evaluate the safety of crude aqueous methanol extract of Annona senegalensis stem bark (AMEAS) through acute and sub-chronic toxicity studies. The stem bark of A. senegalensis was collected, air-dried, pulverized, and extracted using 70% methanol. Phytochemical screening, elemental analysis, and acute toxicity evaluation were carried out on AMEAS. Sub-chronic toxicity study was conducted on Wistar rats of both sexes at different doses administered orally for 28 days. Elemental analysis revealed the presence of heavy metals and essential mineral elements with the highest contents being calcium (59.88%) and potassium (25.39%). Acute toxicity testing showed no mortality up to 5000 mg/kg, suggesting an LD50 greater than 5000 mg/kg. In the sub-chronic toxicity study, no mortality or significant harmful effects were observed. The blood glucose decreased from 13.68 mMol/L at 250 mg/kg to 10.71 mMol/L at 1000 mg/kg, much lower than the distilled water group (17.06 mMol/L). In conclusion, the extract appeared to be well-tolerated, with no obvious adverse effects. AMEAS is rich in Calcium (Ca) and potassium (K). It has been shown to have LD50 greater than 5000 mg/kg and is assumed to be safe. On repeated use, AMEAS may cause hypoglycemia and weight loss which may be useful in managing diabetes and obesity respectively.

Exploring Greater Flexibility for Chronic Toxicity Study Designs to Support Human Safety Assessment While Balancing 3Rs Considerations.

Chronic repeated-dose toxicity studies are required to support long-term dosing in late-stage clinical trials, providing data to adequately characterize adverse effects of potential concern for human safety. Different regulatory guidances for the design and duration of chronic toxicity studies are available, with flexibility in approaches often adopted for specific drug modalities. These guidances may provide opportunities to reduce time, cost, compound requirement and animal use within drug development programs if applied more broadly and considered outside their current scopes of use. This article summarizes presentations from a workshop at the 43rd Annual Meeting of the American College of Toxicology (ACT) in November 2022, discussing different approaches for chronic toxicity studies. A recent industry collaboration between the Netherlands Medicines Evaluation Board (MEB) and UK National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs) illustrated current practices and the value of chronic toxicity studies for monoclonal antibodies (mAbs) and evaluated a weight of evidence (WOE) model where a 3-month study rather than a 6-month study might be adequate. Other topics included potential opportunities for single-species chronic toxicity studies for small molecules, peptides and oligonucleotides and whether a 6-month duration non-rodent study can be used more routinely than a 9-month study (similar to ICH S6(R1) for biological products). Also addressed were opportunities to optimize recovery animal use if warranted and whether restriction to one study only (if at all) can be applied more widely within and outside ICH S6(R1).

Preclinical Safety Evaluation of the Human-Identical Milk Oligosaccharide Lacto-N-Triose II.

Lacto-N-triose II (LNT II), an essential human milk oligosaccharide and precursor to lacto-N-tetraose (LNT) and lacto-N-neotetraose (LNnT), was evaluated for safety. Genotoxicity was assessed through in vitro tests including Bacterial Reverse Mutation Test and mammalian cell micronucleus test, and a subchronic oral gavage toxicity study was conducted on juvenile Sprague-Dawley rats. In this study, LNT II was administered at dose levels of 0, 1,500, 2,500, or 5,000 mg/kg body weight (bw)/day for 90 days, followed by a 4-week treatment-free recovery period. LNT II was non-genotoxic in the in vitro assays. No compound-related effects were observed across all dosage levels based on various measures, including clinical observations, body weight gain, feed consumption, clinical pathology, organ weights, and histopathology. Consequently, the highest dosage of 5,000 mg/kg bw/day was established as the no-observed-adverse-effect-level (NOAEL). These results suggest the safe use of LNT II in young children formula and as a food ingredient, within the limits found naturally in human breast milk.

Toward a Mechanism-Driven Integrated Framework to Link Human Exposure to Multiple Toxic Metal(loid) Species with Environmental Diseases.

The ongoing anthropogenic pollution of the biosphere with As, Cd, Hg and Pb will inevitably result in an increased influx of their corresponding toxic metal(loid) species into the bloodstream of human populations, including children and pregnant women. To delineate whether the measurable concentrations of these inorganic pollutants in the bloodstream are tolerable or implicated in the onset of environmental diseases urgently requires new insight into their dynamic bioinorganic chemistry in the bloodstream-organ system. Owing to the human exposure to multiple toxic metal(loid) species, the mechanism of chronic toxicity of each of these needs to be integrated into a framework to better define the underlying exposure-disease relationship. Accordingly, this review highlights some recent advances into the bioinorganic chemistry of the Cd2+, Hg2+ and CH3Hg+ in blood plasma, red blood cells and target organs and provides a first glimpse of their emerging mechanisms of chronic toxicity. Although many important knowledge gaps remain, it is essential to design experiments with the intent of refining these mechanisms to eventually establish a framework that may allow us to causally link the cumulative exposure of human populations to multiple toxic metal(loid) species with environmental diseases of unknown etiology that do not appear to have a genetic origin. Thus, researchers from a variety of scientific disciplines need to contribute to this interdisciplinary effort to rationally address this public health threat which may require the implementation of stronger regulatory requirements to improve planetary and human health, which are fundamentally intertwined.

Effects of pyroligneous acid on acute, chronic, and cyto-genotoxicity to earthworms (Eisenia fetida).

The pyroligneous acid (PA), or wood vinegar, is a byproduct of wood carbonization during the slow pyrolysis process. PA is recognized globally as a safe compound for agriculture due to its various beneficial properties, such as antioxidant, antibacterial, antifungal, and termiticidal properties. However, the impact of different PA concentrations on beneficial soil organisms, such as earthworms has not been investigated. The present study aims to understand the effects of different PA concentrations on earthworm Eisenia fetida. The earthworms were exposed to nine different concentrations of PA in soils, including their control. The acute toxicity assay was performed after 14 days of exposure, and the chronic toxicity assay was performed up to 8 weeks after exposure. The results from the acute toxicity assay demonstrated no significant effect on earthworm mortality. The chronic toxicity assay showed that lower PA concentrations (0.01-0.2% of weight/weight PA in soil) promoted cocoon and juvenile production in soils, whereas higher PA concentrations (0.5 and 1%) had a negative effect. These findings highlight the potential of PA to enhance soil fertility at lower concentrations, up to 0.2%, by stimulating worm activity and subsequent manure production. The outcomes of this study have significant implications for the careful management of PA concentrations within agricultural operations.

Assessment of Biological Activities, Acute and Sub-chronic Toxicity of Liang (Gnetum gnemon var. tenerum) Leaves Powder, a Natural Product.

Gnetum gnemon var. tenerum (Gnetaceae) is a shrub plant native to South-East Asia. In Thailand, Liang leaves are commonly consumed in South of Thailand as vegetable. According to literature, they have an antihyperglycemic capacity because of their rich chlorophyll, fiber, and protein. However, there is need to assess the safety since natural food products are not completely devoid of toxicity. This study aimed to assess the biological activities as well as the acute and sub-chronic oral toxicity of Liang leaves powder (LLP). The evaluation of LLP for acute oral toxicity was performed at dose level 2000 mg/kg body weight in Wistar rats while the sub-chronic oral toxicity of LLP was performed at the effective dose (1.47 g/kg) for antihyperglycemic property according to Organisation for Economic Co-operation and Development (OECD)-425. The results showed that LLP demonstrated anti-inflammatory activities. It also showed no clinical signs of toxic effects and mortality in rats throughout 90 d. Thus, LLP could be classified in GHS category 5 which are of relatively low acute toxicity and then the lethal dose, 50% (LD50) cut off at 5000 mg/kg body weight to infinity (∞). Administration of LLP to the experimental rats significantly increased (p < 0.05) the concentration of triglyceride and increased concentration of creatinine as a result of kidney malfunction was also noticed in the experimental rats. Hematological alteration was not noticed in the treated female rats, but red blood cell, hemoglobin and hematocrit concentrations significantly increased in the treated male rats. The study concludes that sub-chronic administration of 1.47 g/kg LLP is relatively safe.

Re-evaluating the need for chronic toxicity studies with therapeutic monoclonal antibodies, using a weight of evidence approach.

To support registration of monoclonal antibodies (mAbs) for chronic indications, 6-month toxicity studies have historically been conducted. Experience with mAb development has shown a relatively benign and well-understood safety profile for this class, with most toxicity findings anticipated based on pharmacology. We evaluated whether a 6-month toxicity study is necessary to assess the long-term safety of mAbs. Data on First-in-Human (FIH)-enabling and chronic toxicity studies were shared for 142 mAbs submitted by 11 companies. Opportunities to further optimize study designs to reduce animal usage were identified. For 71% of mAbs, no toxicities or no new toxicities were noted in chronic studies compared to FIH-enabling study findings. New toxicities of potential concern for human safety or that changed trial design were identified in 13.5% of cases, with 7% being considered critical and 2% leading to program termination. An iterative, weight-of-evidence model which considers factors that influence the overall risk for a mAb to cause toxicity was developed. This model enables an evidence-based justification, suggesting when 3-month toxicity studies are likely sufficient to support late-stage clinical development and registration for some mAbs.

Animal use and opportunities for reduction in carcinogenicity studies supporting approved new drug applications in the U.S., 2015-2019.

A minimum of 65,341 rats and mice were used in 109 carcinogenicity studies conducted for new drug applications approved by the U.S. Food and Drug Administration from 2015 through 2019. By analyzing how these animals were used, we compared the potential for reducing animal use of implementing existing international guidelines and recommendations. The greatest reduction, 18.7%, would result from evaluating exposure by microsampling blood in main studies to replace toxicokinetics satellites, which used three-fold more mice than rats. A similar reduction, 17.3%, would result from replacing 33 long-term studies in mice with short-term studies in transgenic mice. Based on histopathology findings in chronic studies, 15 long-term studies in rats could have been waived, using 8410 fewer rats. Simply using single, rather than dual, negative control groups would result in a 7.8% reduction, and eliminating positive control groups would use 640 fewer transgenic mice. Combined, an estimated 46% reduction would be achieved, using approximately 29,876 fewer animals. The publication of an addendum to the main carcinogenicity testing guideline promises to decrease the number of long-term studies conducted in rats and mice and presents opportunity to promote full harmonization and implementation of related recommendations that would further dramatically reduce animal use.

Effects of polycaprolactone degradation products on the water flea, Daphnia magna: Carbodiimide additives have acute and chronic toxicity.

Plastics have benefited our lives in many ways, but their long persistence in the environment causes serious problems. Rapid decomposition and detoxification of plastics after use are significant challenges. As a possible solution, biodegradable plastics have attracted attention, and for environmental risk assessment research on polymer toxicity, use of indicator organisms, like water fleas and fish, has increased globally. However, such research often focuses on standardized substances without considering changes in toxicity due to plastic degradation products. Additionally, tests generally focus on acute toxicity, while long-term effects on organismal reproduction and lifespan are largely unknown. Understanding the impact of degraded polymers on biological activities is crucial for accurate risk assessment. In this study, we investigated the biological toxicity of substances generated during degradation of polycaprolactone (PCL), a common biodegradable plastic, using the indicator organism, Daphnia magna. We examined PCL, oligocaprolactones (OCLs), and monomers resulting from polymer cleavage, as well as carbodiimides, added during polyester synthesis. As a result, PCL, which is insoluble in water, reduced individual survival and total number of offspring at an exposure concentration of 100 mg/L, while no toxicity was observed for water-soluble degradation products, OCLs, and monomers. Furthermore, carbodiimides, which are expected to be released during PCL degradation, showed strong toxicity, significantly reducing individual survival and total number of offspring at 0.1-10 mg/L. These findings suggest that changes in physical properties due to polymer degradation and release of additives can significantly alter their toxicity.

Safety evaluation of rare ginsenosides of stems and leaves from American ginseng: 90-day exposure toxicity study combined with intestinal flora analysis and metabonomics in rats.

Rare ginsenosides have already been widely applied in many fields, including health food and bio-medicine. The human being can expose to rare ginsenosides directly or indirectly increasingly. However, there are few studies on the safety assessment of rare ginsenoside mixtures. In the present study, the sub-chronic toxicity of rare ginsenosides for 90 days on SD rats was performed by combining the intestinal flora analysis and urine metabonomics aiming to illustrate the safety of long-term consumption of rare ginsenosides and the potential damage for liver and intestinal. 48 adult rats were divided into four groups: control (0 mg/kg), low-dose (60 mg/kg), medium-dose (200 mg/kg), and high-dose (600 mg/kg). Rats in the high-dose group showed inflammatory changes in their livers and intestines. The strong bactericidal effect of rare ginsenosides caused intestinal flora disorder and changed the structure of intestinal flora in rats, thus inducing intestinal damage in rats. In the high-dose group, levels of alanine aminotransferase (ALT), lactate dehydrogenase (LDH), and alkaline phosphatase (AKP) increased significantly. As a result of the high-dose treatment, certain metabolic pathways were altered, such as vitamin B6 metabolism, methionine metabolism, glutathione metabolism, and others. These results indicated that high doses of rare ginsenosides induced liver injury by affecting the above metabolic pathways. Rare ginsenosides with no observed adverse effect level (NOAEL) were below 200 mg/kg/day in vivo. Thus, this present study provides insight into the rational use of rare ginsenosides.

Ecotoxicity of pesticide formulations and their mixtures: the case of potato crops in Costa Rica.

Despite their environmental implications, ecotoxicological information regarding pesticide mixtures is relatively scarce. This study aimed to determine the ecotoxicity of individual pesticide formulations and their mixtures (insecticides and fungicides), which are applied during the production cycle of potato, according to agricultural practices from a Latin American region in Costa Rica. Two benchmark organisms were employed: Daphnia magna and Lactuca sativa. First, the evaluation of individual formulations (chlorothalonil, propineb, deltamethrin+imidacloprid, ziram, thiocyclam and chlorpyrifos) revealed differences between available EC50 for active ingredients (a.i.) and their respective formulations toward D. magna; on the contrary, no information could be retrieved from scientific literature for comparison in the case of L. sativa. In general, acute toxicity was higher toward D. magna than L. sativa. Moreover, interactions could not be determined on L. sativa, as the chlorothalonil formulation was not toxic at high levels and the concentration-response to propineb could not be fitted to obtain an IC50 value. The commercial formulation composed of deltamethrin+imidacloprid followed the concentration addition model (when compared with parameters retrieved from individual a.i.) and the other three mixtures evaluated (I: chlorothalonil-propineb-deltamethrin+imidacloprid; II: chlorothalonil-propineb-ziram-thiocyclam; III: chlorothalonil-propineb-chlorpyrifos) produced an antagonistic effect on D. magna, thus suggesting less acute toxicity than their individual components. Subsequent chronic studies showed that one of the most toxic mixtures (II) negatively affected D. magna reproduction at sublethal concentrations indicating that this mixture poses a risk to this species if these pesticides co-exist in freshwater systems. These findings provide useful data to better estimate the impact of real agricultural practices related to the use of agrochemicals.

Joint effects of temperature and copper exposure on developmental and gene-expression responses of the marine copepod Tigriopus japonicus.

There is growing contamination of copper (Cu) in the marine environment, particularly after the ban of organotin compounds and the increase of the use of Cu-based antifouling paints. Although there are increasing research interests in temperature-dependent chemical toxicity to aquatic organisms, most existing studies focused on acute impacts of chemicals at high concentrations. This study aimed to investigate the interacting effect of temperature and copper exposure at environmentally relevant concentrations on survival and development in the marine copepod Tigriopus japonicus with a partial life-cycle toxicity test. Expressions of five stress response genes in the copepod, namely two glutathione S-transferases (GST-S and GST-O), two heat shock proteins (HSP70 and HSP90), and glutathione reductase (GR) were also investigated. The copepod's survival was significantly impaired at 15 °C after development to adult stage, while its developmental time reduced significantly with increasing temperature. Copper at the two environmentally relevant test concentrations had no significant impacts on these apical endpoints whereas the interaction between Cu and temperature was more significant in modulating gene expressions. GST-S, GST-O and HSP90 genes in copepods exposed to 100 µg Cu L-1 were significantly upregulated at 20 °C. At 32 °C, most genes were either insignificantly expressed or down-regulated, compared to the control, likely suggesting that thermal stress inhibited the copepod's antioxidative defense system. Overall, the results revealed that the joint Cu and thermal stresses have significantly elicited antioxidative system in the copepods. It clearly demonstrated the need for more fundamental studies about potential impacts of different environmental factors such as temperature on chemical toxicity under realistic scenario of marine pollution.

Biochemical and histopathological analysis after sub-chronic administration of oxyresveratrol in Wistar rats.

Oxyresveratrol (OXY) is a naturally occurring phenolic compound; however, there are no toxicity studies reported on its long term use. The aim of our work was to demonstrate the evaluation of acute and sub-chronic toxicity of oxyresveratrol in rats to assess its safety profile. To evaluate the LD50 value, 2000 mg/kg of oxyresveratrol was administered to Wistar rats by oral gavage. For sub-chronic toxicity assessment, 80 Wistar rats were randomly divided into four groups (10 animal/sex/group) and oxyresveratrol administered at a dose of 50, 100, 150 mg/kg/day by oral gavage. Bodyweight, food, and water consumption were monitored every week. At the end of the experiments, biochemical and hematological parameters were analyzed. Gross and microscopic organ analyses were also carried out. LD50 of oxyresveratrol was greater than 2000 mg/kg sub-chronic administration of oxyresveratrol did not influence any mortality. Doses of 50 and 100 mg/kg of oxyresveratrol did not produce any sign of toxicity. However, the 150 mg/kg oxyresveratrol group depicted changes in multiple biochemical and hematological parameters with changes in the pathology of cardiac, hepatic, and renal tissues when compared with control. Therefore, no observed adverse effect level (NOAEL) of oxyresveratrol was observed to be 100 mg/kg per day for both male and female rats.