Polystyrene microplastics and di-2-ethylhexyl phthalate co-exposure: Implications for female reproductive health.

Microplastics and phthalates are prevalent and emerging pollutants that pose a potential impact on human health. Previous studies suggest that both microplastics and phthalates can adversely affect the reproductive systems of humans and mammals. However, the combined impact of these pollutants on the female reproductive system remains unclear. Here we show the impacts of exposure to polystyrene microplastics (PS-MPs) and di-2-ethylhexyl phthalate (DEHP) on female Sprague-Dawley rats' reproductive systems. We find that co-exposure to PS-MPs and DEHP results in a marked increase in cystic and atretic follicles, oxidative stress, fibrosis, and dysregulation of serum sex hormone homeostasis in the ovaries of the rats. Proteomic analysis identified differentially expressed proteins that were predominantly enriched in signaling pathways related to fatty acid metabolism and tight junctions, regulated by transforming growth factor ß1 (TGF-ß1). We further confirm that co-exposure to DEHP and PS-MPs activates the TGF-ß1/Smad3 signaling pathway, and inhibiting this pathway alleviates oxidative stress, hormonal dysregulation, and ovarian fibrosis. These results indicate that exposure to the combination of microplastics and phthalates leads to a significant increase in atretic follicles and may increase the risk of polycystic ovary syndrome (PCOS). Our study provides new insights into the reproductive toxicity effects of microplastics and DEHP exposure on female mammals, highlighting the potential link between environmental pollutants and the occurrence of PCOS. These findings highlight the need for comprehensive assessments of the reproductive health risks posed by microplastic pollution to women and contribute to the scientific basis for evaluating such risks.

Polystyrene nanoplastics with different functional groups and charges have different impacts on type 2 diabetes.

BACKGROUND: Increasing attention is being paid to the environmental and health impacts of nanoplastics (NPs) pollution. Exposure to nanoplastics (NPs) with different charges and functional groups may have different adverse effects after ingestion by organisms, yet the potential ramifications on mammalian blood glucose levels, and the risk of diabetes remain unexplored. RESULTS: Mice were exposed to PS-NPs/COOH/NH2 at a dose of 5 mg/kg/day for nine weeks, either alone or in a T2DM model. The findings demonstrated that exposure to PS-NPs modified by different functional groups caused a notable rise in fasting blood glucose (FBG) levels, glucose intolerance, and insulin resistance in a mouse model of T2DM. Exposure to PS-NPs-NH2 alone can also lead the above effects to a certain degree. PS-NPs exposure could induce glycogen accumulation and hepatocellular edema, as well as injury to the pancreas. Comparing the effect of different functional groups or charges on T2DM, the PS-NPs-NH2 group exhibited the most significant FBG elevation, glycogen accumulation, and insulin resistance. The phosphorylation of AKT and FoxO1 was found to be inhibited by PS-NPs exposure. Treatment with SC79, the selective AKT activator was shown to effectively rescue this process and attenuate T2DM like lesions. CONCLUSIONS: Exposure to PS-NPs with different functional groups (charges) induced T2DM-like lesions. Amino-modified PS-NPs cause more serious T2DM-like lesions than pristine PS-NPs or carboxyl functionalized PS-NPs. The underlying mechanisms involved the inhibition of P-AKT/P-FoxO1. This study highlights the potential risk of NPs pollution on T2DM, and provides a new perspective for evaluating the impact of plastics aging.

Co-exposure to polystyrene microplastics and di-(2-ethylhexyl) phthalate aggravates allergic asthma through the TRPA1-p38 MAPK pathway.

Increasing attention has been paid to the potential impact of microplastics (MPs) pollution on human health. MPs and phthalates coexist in the environment, however, the effects of exposure to MPs alone or to a combination of di-(2-ethylhexyl) phthalate (DEHP) and MPs on allergic asthma are unclear. This study investigates the effects of exposure to polystyrene microplastics (PS-MPs) or co-exposure with DEHP, on allergic asthma, and the underlying molecular mechanisms. We established an allergic asthma model using ovalbumin, and mice were exposed to PS-MPs (5 mg/kg bw/day) alone, or combined with DEHP (0.5, 5 mg/kg bw/day), for 28 days. The results showed that in the presence of ovalbumin (OVA) sensitization, exposure to PS-MPs alone slightly affected airway inflammation, and airway hyperresponsiveness, while co-exposure to PS-MPs and DEHP caused more significant damage. Co-exposure also induced more oxidative stress and Th2 immune responses, and activation of the TRPA1 and p38 MAPK pathways. The aggravation of asthmatic symptoms induced by co-exposure to PS-MPs and DEHP were inhibited by blocking TRPA1 ion channel or p38 MAPK pathway. The results demonstrated that co-exposure to PS-MPs and DEHP exacerbates allergic asthma, by exacerbating oxidative stress and inflammatory responses, and activating the TRPA1-p38 MAPK pathway.

The effect and a mechanistic evaluation of polystyrene nanoplastics on a mouse model of type 2 diabetes.

Nanoplastics have become ubiquitous in the global environment and have attracted increasing attention. However, whether there is an influence between exposure to nanoplastics and diabetes is unclear. To determine the effects of exposure to Polystyrene nanoplastics (PS-NPs) and evaluate the underlying mechanisms, mice were orally exposed to PS-NPs at dosages of 1, 10, 30 mg/kg/day for 8 weeks, alone or combined with a high fat diet and streptozocin (STZ) injection. Our data showed that exposure to 30 mg/kg/day PS-NPs alone induced a significant increase in blood glucose, glucose intolerance and insulin resistance. Combined with a high fat diet and STZ injection, PS-NPs exposure markedly aggravated oxidative stress, glucose intolerance, insulin tolerance and insulin resistance, and induced lesions in the liver and pancreas. PS-NPs exposure could decrease the phosphorylation of AKT and GSK3ß, and treatment with SC79, a selective AKT activator, could increase the level of AKT and GSK3ß phosphorylation, effectively alleviating the increase in ROS levels in the liver or pancreas, and slightly attenuating the increase in fasting blood glucose levels and insulin resistance induced by PS-NPs exposure. This showed that exposure to PS-NPs aggravated type 2 diabetes and the underlying mechanism partly involved in the inhibition of AKT/GSK3ß phosphorylation.

Insight into the purification of algael water by a novel flocculant with enhanced branched nanochitosan structure.

For improving inadequate nanostructural stability and promote algal removal efficiency, a novel nanochitosan-grafted flocculant (PAD-g-MNC) with an enhanced branched nanostructure and high molecular weight (MW) was fabricated via maleic anhydride acylation polymerization. Characterization results verified the successful synthesis of the flocculant and the formation of an irregular particle nanostructure. PAD-g-MNC exhibited superior algal and extracellular organic matter (EOM) removal and obtained the turbidity and chlorophyll-a removal rates of 93.46%-95.39% and 95.10%-97.31%, respectively, at the dosage of 4-5 mg L-1. The growth rate, strength factor, and recovery factor of algal flocs flocculated by PAD-g-MNC were 90.36, 0.63, and 0.27 (100 rpm), respectively, and were higher than other flocculants prepared through conventional methods. Results indicated that the high intrinsic viscosity and stability branched nanostructure promoted the formation of stable flocs and regeneration ability of flocs. MW distribution and three-dimensional fluorescence analyses revealed that the special structure of PAD-g-MNC was beneficial to the removal of tryptophan-like proteins in EOM. Strong adsorption-adhesion and bridging-netting effects of the nanostructure chain were the dominated mechanisms in the improvement of flocculation efficiency. This study provided theoretical and experimental guidance for the design of flocculants with superior performance and efficient algal water purification performance.

Formaldehyde causes an increase in blood pressure by activating ACE/AT1R axis.

Previous studies suggest some link between formaldehyde exposure and harmful cardiovascular effects. But whether exposure to formaldehyde can cause blood pressure to rise, and if so, what the underlying mechanism is, remains unclear. In this study, C57BL/6 male mice were exposed to 0.1, 0.5, 2.5 mg/m3 of gaseous formaldehyde for 4 h daily over a three-week period. The systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP) and heart rate (HR) of the mice were measured by tail-cuff plethysmography, and any histopathological changes in the target organs of hypertension were investigated. The results showed that exposure to formaldehyde did cause a significant increase in blood pressure and heart rate, and resulted in varying degrees of damage to the heart, aortic vessels and kidneys. To explore the underlying mechanism, a specific inhibitor of angiotensin converting enzyme (ACE) was used to block the ACE/AT1R axis. We observed the levels of ACE and angiotensin II type 1 receptor (AT1R), as well as the bradykinin (BK) in cardiac cytoplasm. The data suggest that exposure to formaldehyde induced an increase in the expression of ACE and AT1R, and decreased the levels of BK. Strikingly, treatment with 5 mg/kg/d ACE inhibitor can attenuate the increase in blood pressure and the pathological changes caused by formaldehyde exposure. This result has improved our understanding of whether, and how, formaldehyde exposure affects the development of hypertension.

Rapid Seismic Evaluation of Continuous Girder Bridges with Localized Plastic Hinges.

In seismic assessment of continuous girder bridges, plastic hinges form in bridge piers to dissipate seismic energy through nonlinear restoring forces. Considering temporal and spatial variations of ground motions, seismic evaluation of the bridges involves nonlinear stochastic vibration and expensive computation. This paper presents an approach to significantly increase the efficiency of seismic evaluation for continuous girder bridges with plastic hinges. The proposed approach converts nonlinear motion equations into quasi-linear state equations, solves the equations using an explicit time-domain dimension-reduced iterative method, and incorporates a stochastic sampling method to statistically analyze the seismic response of bridges under earthquake excitation. Taking a 3 × 30 m continuous girder bridge as an example, fiber beam-column elements are used to simulate the elastic-plastic components of the continuous girder bridge, and the elastic-plastic time history analysis of the continuous girder bridge under non-uniform seismic excitation is carried out. Results show that the computation time is only 5% of the time of the nonlinear time history approach while retaining the accuracy. This study advances the capability of rapid seismic assessment and design for bridges with localized nonlinear behaviors such as plastic hinges.

Exposure to dibutyl phthalate adsorbed to multi-walled carbon nanotubes causes neurotoxicity in mice by inducing the release of BDNF.

Multi-walled carbon nanotubes (MWCNTs) and dibutyl phthalate (DBP) exist extensively in the environment, and they are easy to form compound pollution through π-π interactions in the environment. We investigate whether DBP, an environmental hormone disruptor, mediated by CNTs can more easily cross the blood-brain barrier, and whether DBP entering the brain has neurotoxic effects on the cells in the brain. Experimental subjects were 40 male Kunming (KM) mice randomly divided into 4 groups: the control group; the MWCNTs group; the DBP group; and the MWCNTs+DBP group. The mice were exposed via tail intravenous injection once every 3 days for 21 days, following which toxicology studies were carried out. The results of behavioral experiments showed that the mice in the combined exposure group (MWCNTs+DBP) exhibited spatial learning and memory impairment, and anxiety-like behavior. Staining of hippocampal sections of mouse brain tissue showed that, in the CA1, CA2, and DG areas, the number of neurons decreased, the nucleus was pyknotic, the cell body was atrophied, and levels of the microglia marker Iba-1 increased. By proteomic KEGG analysis, we found that the DEPs were mainly those related to neurodegenerative diseases. Immunohistochemistry in the hippocampus indicated that the level of brain-derived neurotrophic factor (BDNF) in the DG region was significantly increased. RT-PCR results revealed that the expression levels of P53, caspase3, and Bax genes related to apoptosis were up-regulated. The experimental results demonstrated that the mechanism of the combined-exposure injury to neurons in the hippocampus of mice may be that MWCNTs with adsorbed DBP can induce the release of BDNF, accelerate the apoptosis of neurons, and reduce the number of nerve cells, which activates microglia, causing neuroinflammation and nervous system toxicity.

Lateral Vibration Control of Long-Span Small-Radius Curved Steel Box Girder Pedestrian Bridge with Distributed Multiple Tuned Mass Dampers.

Curved pedestrian bridges are important urban infrastructure with the desired adaptability to the landscape constraints and with aesthetic benefits. Pedestrian bridges feature thin cross-sections, which provide sufficient load capacities but lead to low natural frequencies that make the bridges susceptible to vibration under pedestrian excitation. This study investigates the lateral vibration of a curved bridge with a small radius down to 20 m, proposes an approach to mitigate the lateral vibration of bridges with large curvatures using distributed multiple tuned mass dampers (MTMD), and conducts in-situ bridge tests to evaluate the vibration mitigation performance. The lateral vibration was investigated through in-situ tests and finite element analysis as well as the code requirements. The key parameters of the distributed MTMD system were improved by strategically selecting the mass ratio, bandwidth, center frequency ratio, and damper number. The results showed that the curved bridge was subjected to significant lateral vibration due to the coupling of torque and moment, and the recommended design parameters for the studied bridge were derived, i.e., the total mass ratio is 0.02, bandwidth is 0.15, center frequency ratio is 1.0, and damper number is 3. The proposed approach effectively improves the deployment of MTMD for lateral vibration control of the curved bridge. The field tests showed that the vibration was reduced by up to 82% by using the proposed approach.

The reduction and fate of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) in microbial fuel cell (MFC) during treatment of livestock wastewater.

The fate and removal efficiency of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) in livestock wastewater by microbial fuel cell (MFC) was evaluated by High-throughput quantitative PCR. The results showed that 137 ARGs and 9 MGEs were detected in untreated livestock wastewater. The ARG number of macrolide-lincosamide-streptogramin group B (MLSB), tetracycline and sulfonamide were relatively higher. Throughout the treatment process, the number and abundance of ARGs and MGEs significantly decreased. The relative abundance of tetracycline, sulfonamide and chloramphenicol resistance genes showed the most obvious decreasing trend, and the relative abundance of MGEs decreased by 75% (from 0.012 copies/16S rRNA copies to 0.003 copies/16S rRNA copies). However, the absolute abundance of beta-lactamase resistance genes slightly increased. The operation process of MFC produces selective pressure on microorganisms, and Actinobacteria were predominant and had the ability to decompose antibiotics. The COD removal rate and TN removal rate of livestock wastewater were 67.81% and 62.09%, and the maximum power density and coulomb efficiency (CE) reached 11.49% and 38.40% respectively. This study demonstrated that although the removal of COD and TN by MFC was limited, MFC was quite effective in reducing the risk of antibiotic toxicity and horizontal gene transfer.

Polystyrene microplastics affect learning and memory in mice by inducing oxidative stress and decreasing the level of acetylcholine.

Microplastics pollution has become a growing environmental concern, but its potential neurotoxic effects remain unknown. In this study, we determined the effects of exposure to polystyrene microplastics (micro-PS) on learning and memory, and explored the underlying mechanisms. Kunming mice were orally exposed to 0.01, 0.1, 1 mg/d micro-PS or saline for four weeks. Employing the Morris water maze test, we observed that exposure to micro-PS affected the learning and exploration abilities of mice, and impaired their learning and memory functions. After exposure to micro-PS, the nerve cells in the hippocampus became loose and disordered, and the number of Nissl bodies decreased. Increases in the levels of ROS and MDA, and a decrease in levels of glutathione were found in the brain tissue of the mice exposed to micro-PS. Exposure to micro-PS also induced a reduction in the level of acetylcholine, and inhibited the CREB/BDNF pathway. Importantly, after treatment with the antioxidant, Vitamin E, the learning and memory abilities of the mice were restored, and the release of neurotransmitters rebounded. These results show that micro-PS exposure can affect the learning and memory functions through inducing oxidative stress and decreasing the levels of acetylcholine.

Comparing the effects of polystyrene microplastics exposure on reproduction and fertility in male and female mice.

Microplastics (MPs) may have an impact on the reproductive development of humans and mammals. However, any effects of MPs exposure on male and female reproductive systems and fertility are still ambiguous. In this study, male and female C57BL/6 mice were exposed to saline or 0.1 mg/d polystyrene microplastics (PS-MPs) for 30 days or 44 days to determine the effects of MPs on reproductive systems, following which some of the mice were caged for 10 days to mate to test fertility. Another group of mice were given fluorescent PS-MPs to determine the accumulation of MPs. The results show that PS-MPs exposure resulted in more significant accumulation and oxidative stress in the ovary than in the testis. In male mice, the number of viable epididymis sperm and spermatogenic cells in the testes after PS-MPs exposure was significantly reduced, and the rate of sperm deformity increased. In female mice, PS-MPs exposure induced a decrease in ovary size and number of follicles. After exposure to PS-MPs, the levels of Follicle stimulating hormone, Luteinizing hormone and testosterone were reduced, and the estradiol levels increased in the serum of male mice, while the changes in these hormone levels of female mice was the opposite. The mice exposed to PS-MPs had a reduced pregnancy rate and produced fewer embryos. These findings suggest that exposure to PS-MPs damaged the testes and ovaries, induced oxidative stress, altered the serum hormone levels, and induced changes in reproduction and fertility. Female mice appear to be more susceptible to MPs in reproduction and fertility than male mice.

Phenanthrene induces autism-like behavior by promoting oxidative stress and mTOR pathway activation.

Autism is thought to be associated with both environmental and genetic factors. Phenanthrene (Phe) makes up a relatively high proportion of the low-ring polycyclic aromatic hydrocarbons. However, the association between exposure to Phe and Autism remain unclear. In this study, the effect and mechanisms of phenanthrene exposure on autistic behavior were investigated. Three-week-old male Kunming mice were exposed to doses of 5, 50, or 500 µg/kg/d Phe for 22 days. Exposure to phenanthrene induced a marked decrease in the activity of the mice in the central area in the open field test, and caused a significant decrease in communication with unfamiliar mice in the three-chambered social test. The hippocampus of the mice exposed to high concentrations of Phe showed pathological changes. Exposure to phenanthrene induced an increase in the levels of ROS and a decrease in levels of glutathione, and caused a significant decrease in the expression of Shank3 and Beclin1. This also led to an increase in the phosphorylation levels of Akt and mTOR. However, administering Rapamycin or vitamin E, inhibited the oxidative stress and activation of the mTOR pathway induced by Phe exposure, effectively alleviating the above-mentioned autistic-like anxious social behaviors. These results indicate that exposure to phenanthrene will lead to autism-like behavior. The underlying mechanism involves oxidative stress and the mTOR pathway.

The role and related microbial processes of Mn-dependent anaerobic methane oxidation in reducing methane emissions from constructed wetland-microbial fuel cell.

Anaerobic oxidation of methane (AOM) plays an important role in global carbon cycle and greenhouse gas emission reduction. In this study, an effective green technology to reduce methane emissions was proposed by introducing Mn-dependent anaerobic oxidation of methane (Mn-AOM) and microbial fuel cell (MFC) technology into constructed wetland (CW). The results indicate that the combination of biological methods and bioelectrochemical methods can more effectively control the methane emission from CW than the reported methods. The role of dissimilated metal reduction in methane control in CW and the biochemical process associated with Mn-AOM were also investigated. The results demonstrated that using Mn ore as the matrix and operating MFC effectively reduced methane emissions from CW, and higher COD removal rate was obtained in CW-MFC (Mn) during the 200 days of operation. Methane emission from CW-MFC (Mn) (53.76 mg/m2/h) was 55.61% lower than that of CW (121.12 mg/m2/h). The highest COD removal rate (99.85%) in CW-MFC (Mn) was obtained. As the dissimilative metal-reducing microorganisms, Geobacter (5.10%) was found enriched in CW-MFC (Mn). The results also showed that the presence of Mn ore was beneficial to the biodiversity of CW-MFCs and the growth of electrochemically active bacteria (EAB) including Proteobacteria (35.32%), Actinobacteria (2.38%) and Acidobacteria (2.06%), while the growth of hydrogenotrophic methanogens Methanobacterium was effectively inhibited. This study proposed an effective way to reduce methane from CW. It also provided reference for low carbon technology of wastewater treatment.

The fate of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) from livestock wastewater (dominated by quinolone antibiotics) treated by microbial fuel cell (MFC).

The removal characteristics of antibiotic resistance genes and mobile genetic elements from livestock wastewater (dominated by quinolone antibiotics) treated with MFC were evaluated by High-throughput quantitative (HT-qPCR). The results showed that 144 ARGs and 8 MEGs were detected in the livestock wastewater. After MFC treatment, the number of AGRs decreased as a whole, and the relative abundance of macrolide-lincosamide-streptogramin group B (MLSB) and aminoglycosider decreased by 62.7% and 92.9%, respectively. MGEs decreased by 57.3% and multidrug genes decreased by 90%. After MFC treatment, the absolute abundance of tetracycline in raw sewage decreased by two orders of magnitude from 5.8 × 105 copies L-1 to 5.1.× 103 copies L-1. However, MFC was less efficient in the removal of vancomycin and beta-lactamase genes. It was also found that chloramphenicol resistance genes slightly increased. Illumina sequencing showed that Syntrophobacterales and Synergistales were predominant in MFCs. Desulfovibrio was resistant to high concentration of moxifloxacin hydrochloride. The removal efficiency of MFC for moxifloxacin hydrochloride at a concentration of 5 mg L-1 was 86.55%. The maximum power density and coulomb efficiency were 109.3 mV·cm-3 and 41.97%, respectively. With the increase of antibiotic concentration, the sewage treatment efficiency and electrical performance were inhibited. This study shows that untreated livestock wastewater had a great risk of gene horizontal transfer. Although MFC had limited treatment capacity for high-concentration quinolone wastewater, it is an effective method to reduce ARGs and the risk of horizontal gene transfer.

[Comparative study on arthroscopic anterior cruciate ligament reconstruction with transtibial technique and through anteromedial approach].

OBJECTIVE: To compare the effectiveness of the arthroscopic anterior cruciate ligament (ACL) reconstruction with the transtibial technique and through anteromedial approach. METHODS: Between April 2008 and May 2012, 86 patients (86 knees) with ACL rupture underwent single bundle reconstruction with autogeneic hamstring tendons with the transtibial technique in 44 cases (group A) and through anteromedial approach in 42 cases (group B). There was no significant difference in age, gender, injury causes, injury to admission time, preoperative International Knee Documentation Committee (IKDC) score, and Lysholm score between 2 groups (P > 0.05). The femoral and tibia tunnels were measured by X-ray films and CT. The knee stability and function were evaluated by Lachman test, pivot shift test, IKDC score, and Lysholm score. RESULTS: The patients were followed up 1-2 years (mean, 1.5 years) in group A and 1 year-1 year and 6 months (mean, 1.2 years) in group B. No limitation of knee motion was observed. The Lysholm score and IKDC score were significantly increased at 1 year after operation when compared with preoperative scores in 2 groups (P < 0.05), but no significant difference was found between 2 groups (P > 0.05). At 1 year after operation, the stability of the knee in group B was significantly better than that in group A, and the results of Lachman test and pivot shift test showed significant differences between 2 groups (P < 0.05). The femoral tunnel in group A was significantly longer in length and bigger in coronal angles and sagittal location than that in group B (P < 0.05). CONCLUSION: ACL reconstruction through anteromedial approach is a surgical technique to be closer to anatomy reconstruction, which can obtain better rotation function and stability of the knee than the transtibial technique.

[Cell apoptosis in atrophic skeletal muscle induced by immoblization in rabbits--an experimental study using TUNEL].

This experiment was designed to explore the correlation between the mechanism of immobilization-induced skeletal muscle atrophy and the apoptosis of muscular cells. The models of skeletal muscle atrophy induced by immobilization for different length of time were established according to Sievanen II methods. 24 rabbits, each of them having one hind leg fixed by the tubal plaster and the other one free as control, were randomly divided into four groups depending on time of fixation (3, 7, 14, and 28 days respectively). The animals were sacrificed by the end of fixation. TdT-mediated d-UTP nick end labeling (TUNEL) was used to investigate the apoptotic muscle cells in the animal's bone. By comparing the apoptotic muscle cells with the morphology of the skeletal muscle, the correlation between cell apoptosis and skeletal muscle atrophy were analyzed. Apoptotic muscle cells did appear after immobilization in the atrophied skeletal muscle. In various groups, some cells with false positive stained TUNEL were found in the atrophic muscle, which could be distinguished from apoptotic cells by their characteristics. In conclusion, cell apoptosis participates in the process of skeletal muscle atrophy induced by immobilization; the amount of apoptotic cells is strongly associated with the time of immobilization, its peak appears on the 14th day of immobilization; the distribution of apoptotic skeletal muscle cell varies with the time of fixation. The severity of skeletal muscle atrophy is associated with the degree of the muscle cell apoptosis.