Particles rather than released Zn2+ from ZnO nanoparticles aggravate microplastics toxicity in early stages of exposed zebrafish and their unexposed offspring.

Knowledge on the interaction between microplastics (MPs) and zinc oxide nanoparticles (ZnO NPs) is limited. Here, we investigated effects of embryo-larvae exposure to 500 µg/L polystyrene MPs (5 µm), 1200 µg/L ZnO NPs (< 100 nm), 500 µg/L dissolved Zn2+ from ZnSO4, and the mixtures of MPs and ZnO NPs or ZnSO4 on exposed F0 larvae and unexposed F1 larvae. Consequently, ZnO particles adhered to MPs surfaces rather than Zn2+, and increased Zn transport into larvae. Growth inhibition, oxidative stress, apoptosis, and disturbance of growth hormone and insulin-like growth factor (GH/IGF) axis were induced by MPs and ZnO NPs alone, which were further aggravated by their co-exposure in F0 larvae. MPs + ZnO increased apoptotic cells in the gill and esophagus compared with MPs and ZnO NPs alone. Reduced growth and antioxidant capacity and down-regulated GH/IGF axis were merely observed in F1 larvae from F0 parents exposed to MPs + ZnO. Contrary to ZnO NPs, dissolved Zn2+ reversed MPs toxicity, suggesting the protective role of Zn2+ may be not enough to ameliorate thfie negative effects of ZnO particles. To summarize, we found that particles rather than released Zn2+ from ZnO nanoparticles amplified MPs toxicity in early stages of exposed zebrafish and their unexposed offspring.

Nutritional-status dependent effects of microplastics on activity and expression of alkaline phosphatase and alpha-amylase in Brachionus rotundiformis.

Tissue-nonspecific alkaline phosphatase (ALPL) and alpha-amylase (AMY) are essential in the immune and digestive systems, respectively. Microplastics (MPs) pose a risk to zooplankton which may be in a state of feeding, starvation, or subsequent refeeding. However, molecular characterization of both enzymes and the regulated mechanisms affected by nutritional statuses and MPs remain unclear in zooplankton. In the present study, four full-length genes encoding ALPL and two genes encoding AMY were cloned and characterized from an isolated marine rotifer, Brachionus rotundiformis, including alplA, alplB, alplC, alplD, amy2a, and amy2al. AMY activity and expression of amy2a and amy2al were reduced by starvation and recovered after refeeding compared with feeding. ALPL activity remained unchanged among different statuses, while alplA, alplB and alplD were down-regulated by starvation and refeeding compared with feeding. ALPL activity was not affected by exposure to 10, 100 and 1000 µg/L MPs in rotifers subjected to feeding, starvation and refeeding, whereas AMY activity was significantly enhanced by 1000 µg/L MPs in rotifers subjected to refeeding. Gene expression of the tested genes, except amy2a, was significantly responsive to MPs, especially in the feeding rotifers, depending on MPs concentrations and nutritional statuses. Two-way ANOVA confirmed that these changes were strongly associated with the interaction between MPs concentrations and nutritional statuses. The present study is the first to demonstrate a nutritional status-dependent impact of MPs on immune and digestive responses, and provides more sensitive molecular biomarkers for assessing MPs toxicity using the species as model animals.

Combined effects of polystyrene microplastics and cadmium on oxidative stress, apoptosis, and GH/IGF axis in zebrafish early life stages.

The toxicological interactions of microplastics (MPs) and heavy metals have been paid much attention in aquatic organism. The mechanisms are not fully clear, particularly in fish early life stages. To the end, zebrafish embryos were exposed to 500 µg/L MPs, 5 µg/L cadmium (Cd), and their combination for 30 days. Body weight, adsorption characteristics of Cd onto MPs, Cd accumulation, oxidative stress, apoptosis, and growth hormone/insulin-like growth factor-I (GH/IGF) axis were examined. Exposure to MPs and Cd alone reduced body weight, which was aggravated by co-exposure. An increase in reactive oxygen species (ROS) levels was observed in larvae exposed to Cd or MPs + Cd, suggesting an induction of oxidative stress. Lipid peroxidation levels were not affected by exposure to MPs and Cd alone but dramatically enhanced by co-exposure, which may be explained by the reduction of total antioxidant capacity (TAOC) and activity levels of Mn-superoxide dismutase (Mn-SOD) and catalase (CAT) after co-exposure. Increased apoptotic cells were observed in the vertebral body of larvae exposed to Cd, the esophagus of larvae exposed to MPs, and both organs of larvae exposed to MPs + Cd, which was further confirmed by changes in the activities of Caspase-3, Caspase-8 and Caspase-9. PCR array on the transcription of genes related to growth, oxidative stress and apoptosis was examined, showing that the combined exposure resulted in greater magnitude of changes than MPs and Cd alone. The results indicate that MPs can enhance the negative effects of Cd on growth, oxidative damage and apoptosis in early life stages of zebrafish. However, the adsorption of Cd onto MPs was not observed and the combined exposure did not increase the Cd content in larvae compared to the single Cd exposure, implying that vector role of MPs in Cd uptake is negligible.

Genome-wide identification of seven superoxide dismutase genes in the marine rotifer Brachionus rotundiformis and modulated expression and enzymatic activity in response to microplastics and nutritional status.

Microplastics (MPs) pollution has attracted worldwide attention. Superoxide dismutase (SOD) is a sensitive indicator for assessing the toxic effects of MPs in aquatic organisms. However, few studies have been performed to identify all genes encoding SOD in aquatic invertebrates. Especially, effects of MPs on SOD activity and expression in aquatic organisms under starvation or a subsequent refeeding status are unclear. In the present study, all full-length genes encoding SOD were cloned and characterized from the marine rotifer Brachionus rotundiformis, including CuZnSOD1, CuZnSOD2, CuZnSOD3, CuZnSOD4, CuZnSOD5, MnSOD1, and MnSOD2. The CuZnSOD1, CuZnSOD2 and MnSOD2 are homologous to SODs from vertebrates and the other SOD proteins are rotifer-specific according to the results from the phylogenetic tree. The conserved signature sequences and binding sites of Cu2+, Zn2+and Mn2+ were also identified in the seven SOD proteins. Compared with feeding, starvation down-regulated SOD activity and mRNA expression of CuZnSOD2, CuZnSOD4, CuZnSOD5, MnSOD1 and MnSOD2 while refeeding maintained SOD activity comparable to the feeding level and up-regulated CuZnSOD5 and MnSOD2. Intake of MPs by B. rotundiformis was observed by examining fluorescence signals from the fluorescently-labeled microplastics under different nutritional status. Exposure to MPs reduced rotifer density and increased malondialdehyde (MDA) content and SOD activity in the rotifers under the refeeding condition, but did not affect these indicators under the feeding and starvation conditions. However, mRNA expression of some tested genes was responsive to MPs in the fed, starved and refed rotifers. The present study for the first time demonstrated a nutritional status-dependent effect of MPs on oxidative stress response, and provided more sensitive molecular biomarkers for assessing the toxicity of MPs using B. rotundiformis as a model animal.

Effects of continuous and intermittent cadmium exposure on HPGL axis, GH/IGF axis and circadian rhythm signaling and their consequences on reproduction in female zebrafish: Biomarkers independent of exposure regimes.

Typical biomarkers of cadmium (Cd) pollution have well been confirmed in fish from continuous exposure pattern. However, in a natural environment, fish may be exposed to Cd intermittently. In this study, juvenile female zebrafish were exposed for 48 days to 10 µg/L Cd continuously, 20 µg/L for 1 day in every 2 days or 30 µg/L for 1 day in every 3 days. The toxic effects were evaluated using 8 various physiological and biochemical endpoints like specific growth rate (SGR), 17ß-estradiol (E2) and vitellogenin (VTG) concentrations in plasma, reproductive parameters (gonadosomatic index (GSI), egg-laying amount, spawning percentage, and hatching and mortality rate of embryos). Transcription of 59 genes related to hypothalamic-pituitary-gonadal-liver (HPGL) axis, circadian rhythm signaling and insulin-like growth factor (IGF) system was examined. SGR, spawning percentage, E2 and VTG levels declined in fish exposed to 10 and 20 µg/L Cd but remained relatively stable in fish exposed to 30 µg/L Cd. Exposure to 10, 20 and 30 µg/L Cd significantly reduced GSI, hatching rate and mortality rate. Similarly, mRNA expression of 27 genes were sensitive to both continuous and intermittent Cd exposure. Among these genes, expression levels of 10 genes had more than 5-fold increase or decrease, including mRNA levels of vtg1, vtg2, vtg3, esr1, igf2a, igf2b, igfbp5b, nr1d1, gnrh3 and gnrhr4. The most sensitive molecular biomarker was vtg3 expression with 1500-3100 fold increase in the liver. The present study, for the first time, provides effective candidate biomarkers for Cd, which are independent of exposure regimes.

Waterborne zinc induced lobe-dependent effect on oxidative stress and energy metabolism in hepatopancreas of Larimichthys crocea.

The study aimed to compare differences in oxidative stress and energy metabolism between the left and right lobe of hepatopancreas in large yellow croaker Larimichthys crocea exposed to 0 (control), 20, and 100 µM Zn for 96 h. Tipical biomarkers were examined including the proportion of white hepatopancreas, lipid content, malondialdehyde (MDA) level, glutathione (GSH) content, activity levels of enzymes (Cu/Zn-superoxide dismutase, Cu/Zn-SOD; catalase, CAT; glutathione peroxidase, GPx; glutathione reductase, GR; mitochondrial ATP synthase, F-ATPase; malate dehydrogenase, MDH; succinate dehydrogenase, SDH; hepatic lipase, HTGL; lipoprotein lipase, LPL), mRNA levels of genes encoding these enzymes (sod1, cat, gpx1a, gr, atp5b, mdh, sdh, htgl, and lpl), and gene expression of signaling molecules the NF-E2-related nuclear factor 2 (nrf2) and Kelch-like ECH-associated protein 1 (keap1). A whitish color in the left lobe of hepatopancreas was observed in the control and Zn-exposed fish. Contrarily, the right lobe of hepatopancreas tended towards red with increasing Zn levels. The phenomenon was further confirmed by that lipid content was reduced in the right lobe and was not significantly affected in the left lobe by Zn. The right lobe showed higher energy consumption than the left lobe as reflected by the up-regulation of activity levels of HTGL, LPL, F-ATPase, MDH, and SDH. Lipid peroxidation declined by 20 µM Zn and was unchanged by 100 µM Zn in both lobes, which could be explained by increased activity levels of Cu/Zn-SOD and GPx. However, the magnitude of increase in Cu/Zn-SOD activity was greater in the right lobe than that in the left one. The difference in enzyme activity between two lobes may be involved in changes in mRNA levels of sod1, gr, atp5b, sdh, htgl, lpl, and nrf2, which was further confirmed by positive relationships between enzyme activity and gene expression. Our data also showed positive correlations between nrf2 expression and mRNA levels of its target genes, suggesting that Nrf2 was required for the protracted induction of these genes. Our results demonstrated the potential molecular mechanism of Zn-induced differences between lobes of hepatopancreas, suggesting that the sampling part of hepatopancreas should be considered with caution when assessing metal contamination.

[Locked plating with minimally invasive percutaneous plate osteosynthesis versus intramedullary nailing of distal extra-articular tibial fracture: a retrospective study].

OBJECTIVE: To compare the efficacies of minimally invasive plate osteosynthesis (MIPPO) and interlocking intramedullary nailing (IMN) in the treatment of extra-articular fractures of distal tibia. METHODS: Retrospective reviews were conducted for 126 patients with extra-articular distal tibia fractures. Treatment was either MIPPO (n = 61) or IMN (n = 65). The outcomes were assessed by comparing operating duration, time to union, the last follow-up American Orthopedic Foot and Ankle Society (AOFAS) score and complication rate. RESULTS: The average follow-up period was 23.7 (12-53) months. In the minimally invasive plate osteosynthesis group, there were deep infections (n = 2), superficial infections (n = 5), delayed union (n = 2), malunion (n = 2) and knee joint pain (n = 10) were observed. In addition, the average operating duration (85.9 ± 18.9 min), average time to union (17.3 ± 3.8 weeks) and average AOFAS (83.2 ± 11.9) were analyzed. In the interlocking intramedullary nailing group, there were delayed union (n = 3), malunion (n = 12) and knee joint pain (n = 22). And the average operating duration (83.3 ± 15.7 min), average time to union (16.5 ± 3.1 weeks) and average AOFAS (84.9 ± 12.0) were analyzed. No statistical significance existed in operating duration, time to union and the last follow-up AOFAS between two groups (P > 0.05). However, the rates of malformation and knee joint pain were higher in the intramedullary nail group than those in the plate group. And the difference was statistically significant (P = 0.015, P = 0.025). CONCLUSION: Both MIPPO and IMN are effective for extra-articular fractures of distal tibia. However, the former has the advantage of lowers rate of malformation and knee joint pain. Therefore a surgeon should consider the degree of injury while managing extra-articular fracture of distal tibia.

[Early clinical outcomes of fixed-bearing versus mobile-bearing total knee arthroplasty].

OBJECTIVE: To compare the early clinical outcomes of primary total knee arthroplasty by a fixed-bearing versus mobile-bearing prosthesis. METHODS: A total of 80 patients with osteoarthritis at our hospital from January 2008 to October 2008 were sequentially and randomly assigned into Group A (fixed-bearing prosthesis) (40 knees) and Group B (mobile-bearing prosthesis) (40 knees). And the data of the range of motion (ROM), Knee Society Score (KSS) and Western Ontario MacMaster (WOMAC) were collected at pre-operation and 6, 12 and 24 months post-operation respectively. RESULTS: The P values were as follows: KSS: 0.754, 0.802, 0.561, 0.764; HSS (Hospital for Special Surgery): 0.737, 0.361, 0.254, 0.330; WOMAC (Western Ontario and McMaster Universities) osteoarthritis index: 0.976, 0.557, 0.946, 0.818; ROM follow-up: 0.519, 0.646, 0.175, 0.276. No significant differences were found in clinical outcomes between two groups. CONCLUSION: The fixed-bearing and mobile-bearing prostheses show no difference in clinical outcomes.

[Comparison of no drain or with a drain after unilateral total knee arthroplasty: a prospective randomized controlled trial].

OBJECTIVE: To prospectively compare of no drain or with drain after unilateral total knee arthroplasty (TKA). METHODS: A randomized prospective study was conducted between February 2006 and February 2007. The study included 100 patients who were divided into 2 groups: group A (n = 50), which included patients without drain release, and group B (n = 50), which included patients who had a drain release. The true total blood loss was calculated depending on the height, body mass and pre-and post-operative Hct, and hidden blood loss was gotten by subtracting the visible blood loss from total loss. The recovery after surgery, the correlative complications and transfusion amounts were compared and analyzed. RESULTS: All 100 patients undergoing TKA were involved in the result analysis. In patients without a drain, the total blood loss was (535 +/- 295) ml and the hidden blood loss was (513 +/- 290) ml, in patients with a drain, the total blood loss was (853 +/- 331) ml and the hidden blood loss (689 +/- 324) ml. The total and hidden blood loss, blood transfusion amount between drain-group and without drain-group was significantly different (P < 0.05). The difference in the incidence of infection and post-op recovery and correlative complications did not reach statistical significance. CONCLUSIONS: In patients having primary TKA, using a drain, compared with no use of a drain, does not show us a clear advantage that make us accept it. Without a drain release could present an effective and economic method for reducing blood loss and preventing blood transfusion in patients undergoing unilateral TKA.

Relationship between different skin incisions and the injury of the infrapatellar branch of the saphenous nerve during anterior cruciate ligament reconstruction.

BACKGROUND: After anterior cruciate ligament (ACL) reconstruction, some patients suffered from sensory disturbance around the surgical incision of the leg. This research was aimed to investigate the relationship between the different skin incisions and the injury of the infrapatellar branch of the saphenous nerve (IPBSN) post ACL reconstruction. METHODS: ACL reconstructions were performed with quadruple hamstring tendon for 60 patients. Sensory disturbance around the skin incision was followed up at an average of 14.5 +/- 4.7 months post operation. Among the 60 patients, vertical incision for 35 patients and oblique incision for 25 patients were used for graft taking during ACL reconstruction. The lengths of the incisions were measured. The patients were asked to mark the sensory disturbance zone at follow up time, and then the marked area was measured. The IPBSN of 15 cadaver knees were anatomized. The distance between the IPBSN and the upper edge of the pes anserinus tendon at the middle point of the incision was measured. Independent-samples t-test, chi-square and Mann-Whitney tests were used for statistical analyses. RESULTS: The patients' age (P = 0.329), the follow-up time (P = 0.681), and the incision length (P = 0.732) between the two groups had no significant difference. Twenty-three patients (65.7%) in the vertical incision group had IPBSN injury compared with 6 patients (24.0%) in oblique incision group (P = 0.002). The average sensory disturbance area in vertical incision group ((48.0 +/- 75.3) cm(2)) was significantly larger (P = 0.004) than that in the oblique group ((8.4 +/- 19.4) cm(2)). The anatomy measurement showed the average distance between IPBSN and the upper edge of the pes anserinus tendon was 0.6 cm at the incision. CONCLUSIONS: Oblique incision with less risk of damage for IPBSN may be better for graft harvesting in ACL reconstruction. As the IPBSN is so near and parallel to the hamstring tendons, damage to the IPBSN is one of the potential complications for graft harvesting, regardless of the incision used. That's why even in the oblique incision group, 24% patients also had sensory disturbance complication.