Exposure to polystyrene microplastics causes reproductive toxicity through oxidative stress and activation of the p38 MAPK signaling pathway.

Microplastics (MP) are receiving increased attention as a harmful environmental pollutant, however information on the reproduction toxicity of MP in terrestrial animals, especially mammals, is limited. In this experiment, we investigated the impact of polystyrene microplastics (micro-PS) on the reproductive system of male mice. Healthy Balb/c mice were exposed to saline or to different doses of micro-PS for 6 weeks. The results showed that micro-PS exposure resulted in a significant decrease in the number and motility of sperm, and a significant increase in sperm deformity rate. We also detected a decrease in the activity of the sperm metabolism-related enzymes, succinate dehydrogenase (SDH) and lactate dehydrogenase (LDH), and a decrease in the serum testosterone content in the micro-PS exposure group. We found that micro-PS exposure caused oxidative stress and activated JNK and p38 MAPK. In addition, we found that when N-acetylcysteine (NAC) scavenges ROS, and when the p38 MAPK-specific inhibitor SB203580 inhibits p38MAPK, the micro-PS-induced sperm damage is alleviated and testosterone secretion improves. In conclusion, our findings suggest that micro-PS induces reproductive toxicity in mice through oxidative stress and activation of the p38 MAPK signaling pathways.

Comparing the effects of diethylhexyl phthalate and dibutyl phthalate exposure on hypertension in mice.

Epidemiological studies have shown that high molecular weight phthalates (HMW) such as diethylhexyl phthalate (DEHP), are associated with hypertension in humans, while low molecular weight phthalates (LMW) such as dibutyl phthalate (DBP), have hardly any impact on the elevation of blood pressure. However, the molecular mechanisms responsible for this difference are not completely understood. In this experiment, mice were exposed to 0.1/1/10 mg/kg/day DEHP and 0.1/1/10 mg/kg/day DBP for 6 weeks, and their blood pressure was monitored using the tail pressure method. The results showed that exposure to DEHP dosages of 1 or 10 mg/kg/day resulted in a sharp increase in blood pressure, while exposure to DBP did not induce any significant changes in blood pressure. Investigating the renin-angiotensin-aldosterone system (RAAS) and NO pathway in mice exposed to DEHP, we found that levels of angiotensin-converting enzyme (ACE) and angiotensin II (AngII) increased with increasing exposure to DEHP, and the expression of nitric oxide synthase (eNOS) and the level of NO decreased. Treatment with ACE inhibitor (ACEI) to block the ACE pathway inhibited the enhancement of RAAS expression, inhibited the increase in blood pressure, and inhibited the decrease in NO levels induced by DEHP. However, the expression of ACE, AngII, AT1R, and eNOS in the DBP treatment groups showed no significant changes. When examining estradiol in vivo, we found that exposure to DBP resulted in a significant increase in the level of estradiol, while exposure to DEHP did not lead to a significant change. When ICI182780 was used to block the estradiol receptors, any increase in the level of NO induced by DBP exposure, was inhibited. These results indicate that exposure to DEHP induces an increase in mouse blood pressure through RAAS, and the different effects of DEHP and DBP on blood pressure are partly due to the different estradiol levels induced by DEHP and DBP.

Formaldehyde and co-exposure with benzene induce compensation of bone marrow and hematopoietic stem/progenitor cells in BALB/c mice during post-exposure period.

Formaldehyde (FA) is a human leukemogen. Since there is a latency period between initial FA exposure and the development of leukemia, the subsequent impact of FA on hematopoietic stem or progenitor cells (HSCs/HPCs) in post-exposure stage is crucial for a deep understanding of FA-induced hematotoxicity. BALB/c mice were exposed to 3mg/m3 FA for 2weeks, mimicking occupational exposure, and were monitored for another 7days post-exposure. Meanwhile, we included benzene (BZ) as a positive control, separately and together with FA because co-exposure occurs frequently. After 7-day recovery, colonies of progenitors for CFU-GM and BFU-E, and nucleated bone marrow cells in FA-exposed mice were comparable to controls, although they were significantly reduced during exposure. Levels of reactive oxygen species (ROS) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in CFU-GM and BFU-E from FA-exposed mice were higher than controls, although the increase in 8-OHdG was not significant. Granulocyte-macrophage colony stimulating factor (GM-CSF) level in the FA group was lower than controls, but the expression level for the receptor was not upregulated. It suggests that HSCs/HPCs in FA-exposed mice respond to a small amount of GM-CSF and proliferate rapidly, which may cause a possible risk of expansion of abnormal stem/progenitor cell clones. FA co-exposure with BZ was more potent for promoting CFU-GM formation and inducing ROS in BFU-E and 8-OHdG in CFU-GM during the post-exposure period. The compensation of myeloid progenitors with elevated ROS and 8-OHdG may lead to a risk of transforming normal HSCs/HPCs to leukemic stem/progenitor cells. Thus, co-exposure may pose a greater leukemia risk.

Formaldehyde induces toxicity in mouse bone marrow and hematopoietic stem/progenitor cells and enhances benzene-induced adverse effects.

Formaldehyde (FA) is a human leukemogen and is hematotoxic in human and mouse. The biological plausibility of FA-induced leukemia is controversial because few studies have reported FA-induced bone marrow (BM) toxicity, and none have reported BM stem/progenitor cell toxicity. We sought to comprehensively examine FA hematoxicity in vivo in mouse peripheral blood, BM, spleen and myeloid progenitors. We included the leukemogen and BM toxicant, benzene (BZ), as a positive control, separately and together with FA as co-exposure occurs frequently. We exposed BALB/c mice to 3 mg/m3 FA in air for 2 weeks, mimicking occupational exposure, then measured complete blood counts, nucleated BM cell count, and myeloid progenitor colony formation. We also investigated potential mechanisms of FA toxicity, including reactive oxygen species (ROS) generation, apoptosis, and hematopoietic growth factor and receptor levels. FA exposure significantly reduced nucleated BM cells and BM-derived colony-forming unit-granulocyte-macrophage (CFU-GM) and burst-forming unit-erythroid (BFU-E); down-regulated GM-CSFRα and EPOR expression; increased ROS in nucleated BM, spleen and CFU-GM cells; and increased apoptosis in nucleated spleen and CFU-GM cells. FA and BZ each similarly altered BM mature cells and stem/progenitor counts, BM and CFU-GM ROS, and apoptosis in spleen and CFU-GM but had differential effects on other end points. Co-exposure was more potent for several end points. Thus, FA is toxic to the mouse hematopoietic system, including BM stem/progenitor cells, and it enhances BZ-induced toxic effects. Our findings suggest that FA may induce BM toxicity by affecting myeloid progenitor growth and survival through oxidative damage and reduced expression levels of GM-CSFRα and EPOR.

Formaldehyde-induced paxillin-tyrosine phosphorylation and paxillin and P53 downexpression in Hela cells.

Formaldehyde (FA) is an environmental pollutant and an endogenous product believed to be involved in tumorigenesis. However, the underlying mechanism of observed FA effects has not been clearly defined. Paxillin is a focal adhesion protein that may play an important role in several signaling pathways. Many paxillin-interacting proteins are involved in the regulation of actin cytoskeleton organization, which is necessary for cell motility events associated with diverse biological responses, such as embryonic development, wound repair and tumor metastasis. P53 is important in multicellular organisms, where it regulates the cell cycle and thus functions as a tumor suppressor that is involved in preventing cancer. In this study, we investigated the effects of FA on paxillin-tyrosine phosphorylation and P53 expression in Hela cells by Western blot and immunofluorescence. Western blot analysis revealed that nonlethal concentrations of FA (0.5, 1.0 and 2.0 mM, with the exposure time for 0.5, 1.0 and 2.0 h, respectively) had downregulated paxillin and wild-type p53 genes expression while upregulated paxillin-tyrosine phosphorylation significantly. At the same time, phosphotyrosine at the focal adhesion sites detected by immunofluorescence assay obviously increased in Hela cells incubated with 2.0 mM FA for 2 h. The results suggested that paxillin and p53 genes expression may be involved in FA-related adverse effects and the mechanism may be involved in paxillin-tyrosine phosphorylation.

Self-Powered Biosensors for Monitoring Human Physiological Changes.

Human physiological signals have an important role in the guidance of human health or exercise training and can usually be divided into physical signals (electrical signals, blood pressure, temperature, etc.) and chemical signals (saliva, blood, tears, sweat). With the development and upgrading of biosensors, many sensors for monitoring human signals have appeared. These sensors are characterized by softness and stretching and are self-powered. This article summarizes the progress in self-powered biosensors in the past five years. Most of these biosensors are used as nanogenerators and biofuel batteries to obtain energy. A nanogenerator is a kind of generator that collects energy at the nanoscale. Due to its characteristics, it is very suitable for bioenergy harvesting and sensing of the human body. With the development of biological sensing devices, the combination of nanogenerators and classical sensors so that they can more accurately monitor the physiological state of the human body and provide energy for biosensor devices has played a great role in long-range medical care and sports health. A biofuel cell has a small volume and good biocompatibility. It is a device in which electrochemical reactions convert chemical energy into electrical energy and is mostly used for monitoring chemical signals. This review analyzes different classifications of human signals and different forms of biosensors (implanted and wearable) and summarizes the sources of self-powered biosensor devices. Self-powered biosensor devices based on nanogenerators and biofuel cells are also summarized and presented. Finally, some representative applications of self-powered biosensors based on nanogenerators are introduced.

Application and progress of blood flow restriction training in improving muscle mass and strength in the elderly.

As an emerging training method, blood flow restriction training has been proved to promote the growth of muscle mass and strength. In recent years, it has been gradually applied in different populations. However, there are few studies on how blood flow restriction training affects muscle mass and strength in the elderly. The relevant literature is compiled and summarized in this study. Through the comparison of blood flow restriction training with traditional training methods and its application in the elderly, it shows that blood flow restriction training can effectively increase muscle mass and strength, prevent muscle atrophy, improve cardiopulmonary function, facilitate injury and postoperative rehabilitation, and intervene in related degenerative diseases as a training method suitable for the elderly,. The main mechanism of blood flow restriction training promoting muscle mass and strength growth is metabolic stress response, including muscle fiber recruitment, protein synthesis signal pathway activation, hormone secretion, etc., and is also related to cell swelling caused by pressure. At present, although the application of blood flow restriction training in the elderly population is increasing, there is a lack of personalized programs. In the future, more research on the dose effect and safety of blood flow restriction training is needed to develop more accurate personalized training programs.

Methods and Characteristics of Drug Extraction from Ion-Exchange-Resin-Mediated Preparations: Influences, Thermodynamics, and Kinetics.

Since the discovery of ion-exchange resins, they have been used in many fields, including pharmacy. Ion-exchange resin-mediated preparations can realize a series of functions, such as taste masking and regulating release. However, it is very difficult to extract the drug completely from the drug-resin complex because of the specific combination of the drug and resin. In this study, methylphenidate hydrochloride extended-release chewable tablets compounded by methylphenidate hydrochloride and ion-exchange resin were selected for a drug extraction study. The efficiency of drug extraction by dissociating with the addition of counterions was found to be higher than other physical extraction methods. Then, the factors affecting the dissociation process were studied to completely extract the drug from the methylphenidate hydrochloride extended-release chewable tablets. Furthermore, the thermodynamic and kinetic study of the dissociation process showed that the dissociation process obeys the second-order kinetic process, and it is nonspontaneous, entropy-decreasing, and endothermic. Meanwhile, the reaction rate was confirmed by the Boyd model, and the film diffusion and matrix diffusion were both shown to be rate-limiting steps. In conclusion, this study aims to provide technological and theoretical support for establishing a quality assessment and control system of ion-exchange resin-mediated preparations, promoting the applications of ion-exchange resins in the field of drug preparation.

Effects of silica nanoparticles on growth and photosynthetic pigment contents of Scenedesmus obliquus.

To assess the aquatic ecosystem safety for silica (SiO2) nanoparticles (NPs), the growth inhibition and photosynthetic pigment contents of Scenedesmus obliquus in logarithm growth phase exposed to SiO2 NPs and SiO2 bulk particles (BPs) suspensions were measured. SiO2 NPs with 10-20 nm diameters were found to be toxic. The 20% effective concentration (EC20) values for 72 and 96 hr were 388.1 and 216.5 mg/L, respectively. The contents of chlorophyll decreased significantly under moderate and high concentration (50, 100, and 200 mg/L) of SiO2 NPs after 96-hr exposure, but the carotenoids did not. SiO2 BPs were found to be nontoxic up to 200 mg/L. The toxicity of SiO2 NPs probablely due to their sorption to algal cells surface. The results imply that there is potential harm to aquatic environment by using SiO2 NPs, and it should deserve special concern.

[Comparison of in vitro release behavior of proanthocyanidins flexible nanoliposomes and general nanoliposomes].

OBJECTIVE: To prepare flexible proanthocyanidins nanoliposomes, and explore the in vitro release behavior of proanthocyanidins flexible nanoliposomes and general nanoliposomes. METHOD: Flexible proanthoeyanidins nanoliposomes were prepared proanthocyanidins using a film dispersion method, characterized by transmission electron microscope, and the in vitro release action was studied in different dissolution mediums using dynamic dialyse method with the content of total phenol as index. RESULT: The in vitro release of both proanthocyanidins flexible nanoliposomes and general nanoliposomes were in accordance with Weibull distribution. CONCLUSION: Proanthocyanidins flexible nanoliposomes without pressure had similar in vitro release behavior with general nanoliposomes.

Dermal exposure to nano-TiO2 induced cardiovascular toxicity through oxidative stress, inflammation and apoptosis.

Due to its excellent properties such as ultraviolet obscuration, chemical stability and small particle size, nano-titanium dioxide (nano-TiO2) is widely used, particularly in sunblock products. The skin is therefore a chief route for exposure. Studies have found that oral or respiratory exposure to nano-TiO2 has an adverse impact on the cardiovascular system. The relationship between dermal exposure to nano-TiO2 and cardiovascular system toxicity, particularly the causative mechanisms, remain unclear. In this study, we used Balb/c mice to evaluate cardiovascular toxicity from nano-TiO2 dermal exposure, and the underlying mechanisms associated with the human umbilical vein endothelial cells (HUVECs) were explored. Our results showed that nano-TiO2 treatment resulted in an obvious increase in reactive oxygen species and 8-hydroxy-2'-deoxyguanosine, indicating the appearance of oxidative stress. Moreover, the levels of inflammatory biomarkers, such as immunoglobulin E, soluble intercellular adhesion molecule-1, interleukin-8, and hypersensitive C-reactive protein, also increased. Exposing HUVECs to nano-TiO2 led to a decline in cell vitality, and an increase in caspase-3 levels, suggesting that nano-TiO2 exposure caused cytotoxicity and even cell apoptosis. Interestingly, neutralizing oxidative stress by administering Vitamin E was shown to reduce the inflammatory response and cytotoxicity. Our findings suggest that nano-TiO2 can injure the cardiovascular system via dermal exposure, and does this via oxidative stress-induced inflammation and cytotoxicity. Vitamin E treatment may be a strategy to mitigate the damage.

Mono-butyl phthalate-induced mouse testis injury is associated with oxidative stress and down-regulated expression of Sox9 and Dazl.

Mono-butyl phthalate (MBP) has reproductive toxicity but the related mechanisms have not been fully elucidated in vivo. We exposed male Balb/c mice to MBP by gavage at doses of 0, 25, 50, 100, 200 mg/kg for 14 days, and then evaluated the testicular alterations at the histological and molecular levels. MBP reduced mouse sperm count along with sperm malformation and seminiferous tubule degeneration in a dose-dependent manner. MBP dosed at 200 mg/kg significantly increased reactive oxygen species and malondialdehyde content in mouse testes. High doses of MBP (200 mg/kg) also significantly reduced mRNA expressions of testis growth and function related genes (Sox9 and Dazl). Our findings suggest that oxidative stress and down-regulated expression of Sox9 and Dazl may play important roles in MBP-induced testis injury.

Approach to distribution and accumulation of dibutyl phthalate in rats by immunoassay.

Dibutyl phthalate (DBP) is mainly taken up by the general population from food intake. To estimate intake of phthalates, determining distribution and accumulation of DBP in biological materials was a critical need. In this work, we set up two novel approaches with a monoclonal antibody specific to DBP to determine the distribution and accumulation of DBP in vivo. The contents of DBP in liver, kidney, stomach and testes were detected by immunofluorescence assays and indirect competitive ELISA. This data give directly evidence that indicates the distribution and accumulation of DBP in vivo. Double-label immunofluorescence assay provides with a visual approach to determination of the distribution and accumulation of DBP. It indicated that DBP accumulated in subcutaneous tissue such as sweat gland, hair follicle. Both of immunofluorescence assay and ELISA can be used to detect the content of DBP in biological materials. Our assays showed that DBP accumulated in viscera being rich in fat, such as liver, kidney and could overcome physiological barriers to penetrate testes. The date suggested that the accumulations of DBP exposed through dermal route were less than that of oral route and most of DBP was metabolized in 2 or 3 days.

α-(Substituted-phenoxyacetoxy)-α-heterocyclylmethylphosphonates: synthesis, herbicidal activity, inhibition on pyruvate dehydrogenase complex (PDHc), and application as postemergent herbicide against broadleaf weeds.

Pyruvate dehydrogenase complex (PDHc) is the site of action of a new class of herbicides. On the basis of the previous work for O,O'-dimethyl α-(substituted-phenoxyacetoxy)alkylphosphonates (I), further synthetic modifications were made by introducing a fural and a thienyl group to structure I. A series of α-(substituted-phenoxyacetoxy)-α-heterocyclylmethylphosphonate derivatives (II) were synthesized as potential inhibitors of PDHc. The postemergent activity of the title compounds II was evaluated in greenhouse experiments. The in vitro efficacy of II against PDHc was also examined. Compounds II with fural as R(3) and 2,4-dichloro as X and Y showed significant herbicidal activity and effective inhibition against PDHc from plants. O,O'-Dimethyl α-(2,4-dichlorophenoxyacetoxy)-α-(furan-2-yl)methylphosphonate II-17 had higher inhibitory potency against PDHc from Pisum sativum than against PDHc from Oryza sativa in vitro and was most effective against broadleaf weeds at 50 and 300 ai g/ha. II-17 was safe for maize and rice even at the dose of 900-1200 ai g/ha. Field trials at different regions in China showed that II-17 (HWS) could control a broad spectrum of broad-leaved and sedge weeds at the rate of 225-375 ai g/ha for postemergent applications in maize fields. II-17 (HWS) displayed potential utility as a selective herbicide.

An immunoassay for dibutyl phthalate based on direct hapten linkage to the polystyrene surface of microtiter plates.

BACKGROUND: Dibutyl phthalate (DBP) is predominantly used as a plasticizer inplastics to make them flexible. Extensive use of phthalates in both industrial processes and other consumer products has resulted in the ubiquitous presence of phthalates in the environment. In order to better determine the level of pollution in the environment and evaluate the potential adverse effects of exposure to DBP, immunoassay for DBP was developed. METHODOLOGY/PRINCIPAL FINDINGS: A monoclonal antibody specific to DBP was produced from a stable hybridoma cell line generated by lymphocyte hybridoma technique. An indirect competitive enzyme-linked immunosorbent assay (icELISA) employing direct coating of hapten on polystyrene microtiter plates was established for the detection of DBP. Polystyrene surface was first oxidized by permanganate in dilute sulfuric acid to generate carboxyl groups. Then dibutyl 4-aminophthalate, which is an analogue of DBP, was covalently linked to the carboxyl groups of polystyrene surface with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC). Compared with conjugate coated format (IC(50)=106 ng/mL), the direct hapten coated format (IC(50)=14.6 ng/mL) improved assay sensitivity after careful optimization of assay conditions. The average recovery of DBP from spiked water sample was 104.4% and the average coefficient of variation was 9.95%. Good agreement of the results obtained by the hapten coated icELISA and gas chromatography-mass spectrometry further confirmed the reliability and accuracy of the icELISA for the detection of DBP in certain plastic and cosmetic samples. CONCLUSIONS/SIGNIFICANCE: The stable and efficient hybridoma cell line obtained is an unlimited source of sensitive and specific antibody to DBP. The hapten coated format is proposed as generally applicable because the carboxyl groups on modified microtiter plate surface enables stable immobilization of aminated or hydroxylated hapten with EDC. The developed hapten coated icELISA can be used as a convenient quantitative tool for the sensitive and accurate monitoring DBP in water, plastic and cosmetic samples.

Studies of O,O-dimethyl α-(2,4-dichlorophenoxyacetoxy)ethylphosphonate (HW02) as a new herbicide. 1. Synthesis and herbicidal activity of HW02 and analogues as novel inhibitors of pyruvate dehydrogenase complex.

On the basis of the previous work for optimization of O,O-diethyl α-(substituted phenoxyacetoxy)alkylphosphonates, further extensive synthetic modifications were made to the substituents in alkylphosphonate and phenoxy moieties of the title compounds. New O,O-dimethyl α-(substituted phenoxyacetoxy)alkylphosphonates were synthesized as potential inhibitors of pyruvate dehydorogenase complex (PDHc). Their herbicidal activity and efficacy in vitro against PDHc were examined. Some of these compounds exhibited significant herbicidal activity and were demonstrated to be effective inhibitors of PDHc from three different plants. The structure-activity relationships of these compounds including previously reported analogous compounds were studied by examining their herbicidal activities. Both inhibitory potency against PDHc and herbicidal activity of title compounds could be increased greatly by optimizing substituent groups of the title compounds. O,O-Dimethyl α-(2,4-dichlorophenoxyacetoxy)ethylphosphonate (I-5), which acted as a competitive inhibitor of PDHc with much higher inhibitory potency against PDHc from Pisum sativum and Phaseolus radiatus than from Oryza sativa , was found to be the most effective compound against broadleaf weeds and showed potential utility as herbicide.