Male reproductive toxicity of polystyrene microplastics: Study on the endoplasmic reticulum stress signaling pathway.

Microplastics (MPs) have raised health concerns in public for its potential reproductive toxicity. In this study, we subjected the Kunming mice to 0.01, 0.1 and 1.0 mg/day polystyrene MPs (10 µm, PS-MPs) for 35 days, aiming to investigate the relevant male reproductive toxicity and latent molecular mechanism. The results showed the decreased sperm counts and motility, while the elevated sperm abnormality in PS-MPs-exposed mice. Testicular H&E staining displayed the vacuolization, atrophy, and even shedding of germ cells in seminiferous tubule. And the testosterone content in serum also decreased with PS-MPs treatment. Moreover, molecular analysis indicated that PS-MPs upregulated the expression trait factors for ERS (e.g., immunoglobulin-binding protein [BIP], inositol-requiring protein 1α [IRE1α], X-box-binding protein 1 splicing [XBP1s], Jun kinase [JNK], and the transcription of CCAAT/enhancer-binding protein (C/EBP) homologous protein [CHOP]) and downstream apoptotic modulator (e.g., Caspase-12, -9, and -3) in the testis. The steroidogenic acute regulatory protein (StAR), the testosterone synthetic initiator, was also downregulated. With the supplementation of ERS inhibitor, the MPs-induced testicular damage and decreased testosterone were improved to almost normal level. Overall, this study suggested that PS-MPs generate reproductive toxicity possibly via activating ERS and apoptosis signaling pathway.

Electroacupuncture Reduces Cerebral Hemorrhage Injury in Rats by Improving Cerebral Iron Metabolism.

Objective: To study the effects of electroacupuncture at Baihui and Dazhui points on the expression of hepcidin (Hepc), transferrin (Tf), transferrin receptor (TfR), and ferritin (Ft) in rats with cerebral hemorrhage to provide a theoretical basis for the treatment of cerebral hemorrhage with acupuncture. Method: The model of cerebral hemorrhage in rats was established by autologous blood injection method and treated by electroacupuncture (EA) at the acupoints of Baihui and Dazhui. Hepc siRNA was injected into the lateral ventricle 30 min before model preparation to produce the cerebral hemorrhage model. The modified neurological severity score (mNSS) was used to assess the neurological function, and the total iron content in brain tissue was determined using atomic absorption spectrometry; the expression of Hepc, Ft, Tf, and TfR in perihematoma tissue was detected using immunohistochemistry; the interference efficiency of Hepc siRNA was detected using western blot and reverse transcription polymerase chain reaction (RT-PCR). Results: The degree of neurological deficit showed a downward trend at 3 days, 7 days, and 14 days, and electroacupuncture significantly reduced the neurological deficit score at each time point (P < 0.01). Regarding total iron content in brain tissue, on the 3rd day, the 7th day, and the 14th day, the iron content of the hematoma tissue after intracerebral hemorrhage was reduced by electroacupuncture (P < 0.01). Regarding immunohistochemical results. Hepc, Ft, Tf, and TfR protein expressions on day 14 were significantly higher after cerebral hemorrhage (P < 0.01). After electroacupuncture, the expression of Hepc, Ft, Tf, and TfR protein was significantly reduced (P < 0.01). Western blot and RT-PCR revealed that the interference efficiency of Hepc siRNA was statistically significant (P < 0.01). Conclusion: Electroacupuncture can reduce neurological severity scores in rats with cerebral hemorrhage and may exert cerebral protective effects by reducing Hepc protein and gene expression; lowering Ft, Tf, and TfR protein expression; and promoting iron metabolism in the brain of rats with cerebral hemorrhage.

Pre-Exposure to TiO2-NPs Aggravates Alcohol-Related Liver Injury by Inducing Intestinal Barrier Damage in Mice.

The wide application of titanium dioxide nanoparticles (TiO2-NPs) and the increase in opportunities for its release into the environment undoubtedly compound the potential of these materials to harm people. Research on the effects of pre-exposure to TiO2-NPs on disease development is scarce. The purpose of this work was to assess whether pre-exposure to TiO2-NPs (20 and 200 mg/kg) for 28 days aggravates the development of alcohol-related liver injury in mice. Results showed that oral administration of 200 mg/kg TiO2-NPs induced only modest changes in liver function parameters, but could induce intestinal inflammation and destroy the integrity of intestinal barrier. After the subsequent alcohol intervention, pre-exposure to TiO2-NPs (200 mg/kg) was found to aggravate alcohol-related liver injury, including significantly increases in serum aspartate aminotransferase, alanine aminotransferase, total glycerol, and total cholesterol, as well as steatosis and inflammation in the liver. Further investigation revealed that alcohol could increase intestinal permeability and reduce the expression of tight junction proteins in mice pre-exposed high dosage of TiO2-NPs, thereby inducing the transfer of more lipopolysaccharides into the liver, ultimately triggering more severe liver inflammation. This study emphasizes that pre-exposed of TiO2-NPs (high doses of up to 200 mg/kg) can potentially promote the development of alcoholic liver diseases. Furthermore, this study provides new insights into evaluating the safety of NPs.

TiO2 NPs induce the reproductive toxicity in mice with gestational diabetes mellitus through the effects on the endoplasmic reticulum stress signaling pathway.

The effect of one of the most widely studied nanomaterials at present, TiO2 nanoparticles (NPs), on pregnancy-related diseases is not clear. In this study, the adverse effects of TiO2 NPs on mice with gestational diabetes mellitus (GDM) and their possible mechanism were investigated. GDM mice were orally administered 0, 10, 50 and 250 mg/kg TiO2 NPs for 14 days. GDM reduced the weight of pregnant mice, destroyed the placental structure and caused abnormal fetal development. After exposure to increasing doses of TiO2 NPs, blood glucose levels increased significantly and body weight further decreased in GDM mice. The accumulation of the Ti content was detected in the placenta and fetus, which may further damage the placental structure in GDM mice, thereby exacerbating abnormal fetal development. In addition, the MDA and SOD activities were obviously increased, and the expression of genes associated with endoplasmic reticulum stress (ERS) (PERK, eIF2α, AFT4, IRE1α, and XBP1s) and apoptosis (CHOP, JNK, Bax/Bcl-2, Caspase-12, Caspase-9, and Caspase-3) were also obviously increased in the placenta, which reflected the possible activation of apoptosis. It could be speculated that the reproductive toxicity of TiO2 NPs in GDM mice triggered oxidative stress that subsequently activated ERS pathways to induce cell apoptosis.

Inhibition of testosterone synthesis induced by oral TiO2 NPs is associated with ROS-MAPK(ERK1/2)-StAR signaling pathway in SD rat.

Titanium dioxide nanoparticles (TiO2 NPs) have been widely used in food, medical, and other fields; their reproductive toxicity has been reported in numerous studies. However, the relevant toxicity mechanism still requires further exploration. In this paper, the effect of oral exposure to 500 mg/kg TiO2 NPs (anatase and rutile) in adult male SD rats was studied over 3 and 7 days. Results showed that the total sperm count and testosterone level of 7 days of exposure in serum decreased in the experimental group. Testicular tissue lesions, such as disappearance of Leydig cells, disorder of arrangement of spermatogenic cells in the lumen of convoluted seminiferous tubules, and disorder of arrangement of germ cells, were observed. Meanwhile, the expression of steroidogenic acute regulatory (StAR; the key factors of testosterone synthesis), MAPK (ERK1/2), and phosphorylated ERK1/2 in testes of SD rats after exposure to TiO2 NPs for 7 days decreased, while the malondialdehyde content increased and superoxide dismutase activity decreased in serum. The present study showed that TiO2 NPs could cause reproductive toxicity. Notably, anatase is more toxic than rutile. In addition, exposure to 500 mg/kg TiO2 NPs for 7 days inhibited testosterone synthesis in male rat, which may be related to the reactive oxygen species (ROS)-MAPK (ERK1/2)-StAR signal pathway. Warning that the use of TiO2 NPs should be regulated.

Lactobacillus rhamnosus GG Ameliorated Long-Term Exposure to TiO2 Nanoparticles Induced Microbiota-Mediated Liver and Colon Inflammation and Fructose-Caused Metabolic Abnormality in Metabolism Syndrome Mice.

A huge number of titanium dioxide nanoparticles (TiO2 NPs) exist in confectionery foods, which is a high-risk factor for development of diet-induced metabolism syndrome (MetS). In this study, we built a high fructose drinking-induced MetS mouse model, and oral intake of 20 mg/kg TiO2 NPs was administered for 8 weeks. Significant pathological changes and inflammatory factors of overproduction were detected in the liver and colon. The 16S rDNA sequencing analysis results indicated that TiO2 NPs evidently and further perturbed the gut microbiota diversity, compositions, and KEGG pathways in MetS mice. Fecal microbiota transplant experiment proved that TiO2 NPs-altered gut microbiota drives liver and colon inflammation damage. More importantly, oral supplementation of Lactobacillus rhamnosus GG (LGG) ameliorated not only the TiO2 NPs-induced inflammation but also the fructose-caused metabolic abnormality. LGG recovered the gut dysbiosis and decreased the abundance of inflammation-related bacteria (Desulfovibrionaceae, Clostridia, and Proteobacteria), thereby protecting against TiO2 NPs-induced severe inflammation damage. Our study suggests the necessity of assessing the toxic effects of foodborne nanoparticles on the chronic disease population and potential usefulness of probiotics as prophylactic and therapeutic.

Foodborne TiO2 Nanoparticles Induced More Severe Hepatotoxicity in Fructose-Induced Metabolic Syndrome Mice via Exacerbating Oxidative Stress-Mediated Intestinal Barrier Damage.

The hazard of titanium dioxide nanoparticles (TiO2 NPs) in diseased population should be given focus due to the huge number of these NPs in foods and medicine. This study aimed to evaluate the stronger biological adverse effect of oral exposure to TiO2 NPs in a fructose-induced metabolic syndrome mouse model. Compared to the normal mice, low-dose (2 mg/kg) TiO2 NPs did not cause severe hepatotoxicity. However, high-dose (20 mg/kg) TiO2 NPs induced aggravated hepatic inflammation, fibrosis, and apoptosis, with substantial alteration of related biochemical parameters in the mouse model. Moreover, significantly increased Ti and lipopolysaccharide burden were observed in metabolic syndrome murine liver and serum, which possibly worsened the portend intestinal leakage. The expression of tight junction-related protein showed that TiO2 NPs induced further increase in serious intestinal permeability. The intestinal inflammatory and oxidative stress response in the model were also assessed. Results showed that TiO2 NPs caused more severe intestinal inflammatory injury by intensifying the oxidative stress in metabolic syndrome mice and then induced further liver injury. This work provides information on the insights into the toxic effect of TiO2 NPs in sub-healthy population.

Toxic effects of TiO2 NPs in the blood-milk barrier of the maternal dams and growth of offspring.

Titanium dioxide nanoparticles (TiO2 NPs) are amongst the most frequently used nanomaterial in everyday consumer products, and their widespread applications have raised concerns of the consequent deleterious effects on human health, particularly to vulnerable populations, such as lactating females remains elusive. Therefore, this study was initiated to investigate the detrimental effects and toxic mechanisms induced by TiO2 NPs in maternal dams and offspring during the lactation period. Dams were randomly divided into three groups. The water (Control; Group I) and TiO2 NPs (100 mg/kg; Group II) were orally administered from postnatal day 1-20, respectively. The results indicated that TiO2 NPs could cause toxicity in the dams, such as pathological damages to mammary gland tissues. The excessive accumulation of TiO2 NPs could induce oxidative stress in the mammary gland, leading to the dysfunctional blood-milk barrier; besides, TiO2 NPs could also be transferred to offspring via breastfeeding, causing abnormal development of infant. We further accessed the possible underlying molecular mechanism; for this, we orally administered TiO2 NPs with vitamin E (100 mg/kg; Group III). The results revealed that toxicity induced by TiO2 NPs was rescued. Collectively, this study presented the deleterious pathological effects of oral exposure to TiO2 NPs in the mammary gland tissues and blood-milk barrier via the production of reactive oxygen species (ROS) in dams and developmental concerns in offspring. However, the administration of VE could mitigate the toxic effects induced by the TiO2 NPs.

Oral Exposure to ZnO Nanoparticles Disrupt the Structure of Bone in Young Rats via the OPG/RANK/RANKL/IGF-1 Pathway.

PURPOSE: To evaluate the effects of ZnO NPs on bone growth in rats and explore the possible mechanisms of action. MATERIALS AND METHODS: Three-week-old male rats received ultrapure water or 68, 203, and 610 mg/kg zinc oxide nanoparticles (ZnO NPs) for 28 days, orally. RESULTS: The high-dosage groups caused significant differences in weight growth rate, body length, and tibia length (P<0.05), all decreasing with increased ZnO NP dosage. There were no significant differences in body mass index (BMI) (P>0.05). The zinc concentration in liver and bone tissue increased significantly with increased ZnO NP dosage (P<0.05). Clearly increased aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were observed in the 610 mg/kg ZnO NP group (P>0.05), whereas alkaline phosphatase (ALP) increased in the 610 mg/kg ZnO NP group (P<0.05). Significant differences in insulin-like growth factor type 1 (IGF-1) levels and a decrease in calcium (Ca) levels were observed in 203 and 610 mg/kg ZnO NP groups (P<0.05). Phosphorus (P) levels increased and the Ca/P ratio decreased in the 610 mg/kg ZnO NP group (P<0.05). Micro-computed tomography (micro-CT) of the tibia demonstrated signs of osteoporosis, such as decreased bone density, little trabecular bone structure and reduced cortical bone thickness. Micro-CT data further demonstrated significantly decreased bone mineral density (BMD), trabecular number (Tb.N), and relative bone volume (BV/TV) with increasing dosage of ZnO NPs. Osteoprotegerin (OPG) expression and the ratio of OPG to receptor activator of nuclear factor-κB ligand (RANKL) were statistically lower in the 610 mg/kg ZnO NP group (P<0.05), whereas RANKL expression did not change significantly (P>0.05). CONCLUSION: We infer that ZnO NPs affect bone growth in young rats directly or indirectly by altering IGF-1 levels. Overall, the results indicate that ZnO NPs promote osteoclast activity and increase bone loss through the OPG/RANK/RANKL/IGF-1 pathway.

Restraining the TiO2 nanoparticles-induced intestinal inflammation mediated by gut microbiota in juvenile rats via ingestion of Lactobacillus rhamnosus GG.

Human were given a lot of opportunities to ingest TiO2 NPs in the environment. Children have low, sensitive intestinal tolerance, and they could be exposed to higher levels of TiO2 NPs than adults. Few studies have been conducted on the interaction between TiO2 NPs and juvenile intestine phase models. Thus, in this work, weaning rats were orally exposed to TiO2 NPs for 7 and 14 days. Results indicate that Ti accumulated in the intestine, liver, and feces. Inflammatory infiltration damage was observed in the colonic epithelial tissue, and gut microbiota fluctuated with a decreased abundance of Lactobacilli in feces. Oral supplementation with Lactobacillus rhamnosus GG (LGG) lessened TiO2 NPs-induced colonic inflammatory injury, which might due to downregulation of nuclear factor kappa-B (NF-κB). Meanwhile, LGG maintained normal intestinal microbiome homeostasis, thereby improving TiO2 NPs-induced colon injury in juvenile rats. Moreover, fecal microbiota transplant (FMT) experiment indicated possible TiO2 NPs-induced intestinal microbiota disorder led to colonic inflammation. Our works suggested the urgent need for additional studies on the risk safety assessment, mechanism, and prevention of juvenile health damage from exposure to TiO2 NPs.

Protective effect of the NAC and Sal on zinc oxide nanoparticles-induced reproductive and development toxicity in pregnant mice.

The growing use of zinc oxide nanoparticles (ZnO NPs) in various applications has raised many concerns about the potential risks to human health. In this research, the protective effects of cellular oxidative stress inhibitor N-Acetyl-cysteine (NAC) and endoplasmic reticulum (ER) stress inhibitor Salubrinal (Sal) on reproductive toxicity induced by ZnO NPs were investigated. The results showed that application of these two kinds of cell stress inhibitors after oral ingestion of ZnO NPs could prevent the weight loss of pregnant mice; reduce zinc content in the uterus, placenta and fetus; reduce abnormal development of the offspring; and decrease fetal abortion. Furthermore, RT-qPCR, Western blot and immunofluorescence assay results indicated that NAC restored the expression of Gclc, reduced the expression of ATF4, JNK and Caspase-12, and decreased the expression of eNOS and IGF-1, in the placenta. Sal decreased the expression of ATF4, JNK and Caspase-12, and increased the expression of eNOS and IGF-1caused by the oral ingestion of ZnO NPs. These results indicated that treatment with NAC and Sal after oral exposure could reduce reproductive and development toxicity caused by ZnO NPs which induced reproductive and development toxicity that was probably caused by the activation of oxide stress and ER stress.

Oral exposure of titanium oxide nanoparticles induce ileum physical barrier dysfunction via Th1/Th2 imbalance.

In this work, we aimed to evaluate the adverse effects and the mechanism of intestinal barrier caused by titanium dioxide nanoparticles (TiO2 NPs). Here, the effects of two different dosages (300 and 1200 mg/kg) of TiO2 NPs on female mice (n = 5) were investigated. After 28-day oral exposure, the results of Ti content were significantly increased in the ileum in comparison with the control. The histopathological structure index of the ileum was significantly changed after TiO2 NPs exposure; villi height and crypt depth were decreased and increased, respectively. Meanwhile, TiO2 NPs treatment also significantly altered the transcription levels of genes. First, the GATA-3 and STAT-4 were upregulation and downregulation, respectively. Second, gene expressions of the Zonula Occludens-1, claudin (CLDN)-12, occludin, and myosin light chain kinase were significantly upregulated, while the CLDN-3 was decreased. Finally, the caspase-3, caspase-9, and caspase-12 were upregulated. The results of TUNEL staining indicated apoptosis in the ileum. In general, TiO2 NPs treatment significantly changed the intestine physical barrier in a dose-dependent manner. The toxicity of TiO2 NPs could be through the imbalance in the Th1/Th2.

Nano Zinc Oxide Induced Fetal Mice Growth Restriction, Based on Oxide Stress and Endoplasmic Reticulum Stress.

ZnO NPs have been assessed to show adverse effects on reproductive organs, but the molecular mechanisms of reproductive toxicity have not been sufficiently studied. In this research, the dosage effects from the oral exposure of ZnO NPs (30 nm) to pregnant mice in gestation day 10.5 to 17.5 was analyzed. Pregnant mice exposed to ZnO NPs induced dam injury, mice fetal growth restriction, and the fetus number decreased. The pathological evaluation showed that ZnO NPs exposure caused placental spongiotrophoblast area decease and structural damage. The RT-qPCR and immunocytochemistry data indicated that ZnO NPs could induce placenta oxide stress, endoplasmic reticulum stress responses, apoptosis, and altered placental function. These findings indicated that ZnO NPs could induce dam injury and fetal growth restriction. Reproductive toxicity of ZnO NPs may be due to placental injury and function alteration caused by apoptosis, oxide stress, and endoplasmic reticulum stress after ZnO NPs exposure.

ZnO Nanoparticles Induced Male Reproductive Toxicity Based on the Effects on the Endoplasmic Reticulum Stress Signaling Pathway.

PURPOSE: The aim of this study was to evaluate the adverse effects of ZnO NPs on male reproductive system and explore the possible mechanism. METHODS: In this study, the effect of oral administration of 50, 150 and 450 mg/kg zinc oxide nanoparticles (ZnO NPs) in adult male mice was studied over a 14-day period. RESULTS: The results showed that the number of sperms in the epididymis and the concentration of testosterone in serum were decreased with an increased dose of ZnO NPs. Testicular histopathological lesions like detachment, atrophy and vacuolization of germ cells were observed. The results showed that increased dosage of ZnO NPs correspondingly up-regulated the IRE1α, XBP1s, BIP, and CHOP (P<0.05) which are genes related to ER stress. These observations indicated that ZnO NPs had adverse effects on the male reproductive system in a dose-dependent manner possibly through ER stress. The expression of caspase-3 was significantly increased in all the treated groups (P<0.001), which reflected the possible activation of apoptosis. Additionally, there was significant down-regulation of the gene StAR (P<0.05), a key player in testosterone synthesis. When an ER-stress inhibitor salubrinal was administered to the 450 mg/kg ZnO NPs treatment group, the damages to the seminiferous tube and vacuolization of Sertoli and Leydig cells were not observed. Furthermore, the testosterone levels in the serum were similar to the control group after the subsequent salubrinal treatment. CONCLUSION: It may be inferred that the ZnO NP's reproductive toxicity in male mice occurred via apoptosis and ER-stress signaling pathway.

[Progress in rolling circle amplification in biological detection].

Rolling circle amplification is a rapid, sensitive and isothermal single-stranded DNA amplification technique that can be used with staining or probes to amplify the detection signal. This technology has been widely used in biological detection and other aspects. The present paper introduces how to design rolling circle amplification, summarize its application in the detection of pathogens, nucleic acid tumor markers, proteins, biological small biomolecules, and viruses in recent years and prospects for future development.

Residual Gastric Dilatation Interferes with Metabolic Improvements Following Sleeve Gastrectomy by Upregulating the Expression of Sodium-Glucose Cotransporter-1.

OBJECTIVE: Sleeve gastrectomy (SG) is widely used in treating obesity because of significant weight loss and anti-diabetic effects, but there are still cases of long-term weight loss failure. Our aim was to explore the weight loss mechanism following SG in mice to learn how initial improvements in glucose metabolism are reversed in the long term. METHODS: C57/BL6 mice were divided into two groups, one undergoing SG and the other sham surgery. Body weight, gastric volume, blood glucose level, and the expression of sodium-glucose cotransporter 1 (SGLT1) were assessed at 2 weeks, 1 month, and 2 months after surgery. RESULTS: The SG mice had reduced food intake and lost weight during the 30 days after surgery. However, food intake and weight recovered gradually and even surpassed the sham group after 30 days. SGLT1 expression decreased within 1 month after SG and then increased at 2 months. Although initial SGLT1 expression levels in the stomach were much lower than at intestinal sites, levels increased following surgery and then decreased. The gastric volume decreased after SG, but was significantly increased at 2 months, exceeding the gastric volume in the sham mice. CONCLUSIONS: The metabolic benefits of SG are achieved through reduced gastrointestinal glucose absorption as evidenced by decreased expression of SGLT1 without bypassing the proximal intestine as in other forms of bariatric surgery. In addition, SGLT1 expression in the stomach may play a greater role in post-surgical metabolic effects, but further studies are needed.