Joint toxic effects of cadmium and four pesticides on the earthworm (Eisenia fetida).

The contaminants, instead of single contaminants, are usually found as chemical mixtures in terrestrial environment. However, little information is now available about the joint effects of heavy metals and farm chemicals on the soil organism. Our current study aimed to assess the combined toxicity of cadmium (Cd) and four pesticides (atrazine, chlorpyrifos, lambda-cyhalothrin and abamectin) to the earthworm (Eisenia fetida) with binary, ternary, quaternary and quinquenary mixtures. Two distinct kinds of bioassay systems were applied in this study, including contact filter paper test and artificial soil test. Synergistic effects were observed from two quaternary mixtures (Cd-Atrazine-Chlorpyrifos-Lambda-cyhalothrin and Cd-Chlorpyrifos-Lambda-cyhalothrin-Abamectin) and one quinquenary mixture (Cd-Atrazine-Chlorpyrifos-Lambda-cyhalothrin-Abamectin) in both bioassay systems. Besides, two binary mixtures (Cd-Atrazine and Cd-Lambda-cyhalothrin) and three ternary mixtures (Cd-Atrazine-Chlorpyrifos, Cd-Atrazine-Lambda-cyhalothrin and Cd-Chlorpyrifos-Lambda-cyhalothrin) also exhibited synergistic effects on E. fetida by the soil toxicity test. It is more practical to evaluate the contaminant toxicities to earthworm by soil toxicity test. Therefore, the effects of chemical mixtures on soil invertebrates might be underestimated by data obtained from single toxicant. Our findings would offer a better understanding of the complex effects of chemical mixtures on non-target living creatures, and these findings provided valuable insights into the interplay of different chemicals in natural environment.

Multi-level ecotoxicological effects of imidacloprid on earthworm (Eisenia fetida).

As a neurotoxic insecticide, imidacloprid (IMI) has been widely used for crop protection. However, continuous application of such pesticide in the environment may damage the non-target organisms in soil. In the present study, we aimed to investigate the effects of IMI on earthworms in terms of survival, avoidance behavior, reproduction, detoxification enzyme activity and gene expression using a systematic experimental approach. The results showed that the 14-day LC50 value of IMI was 2.26 (2.09-2.43) mg a.i. kg-1, and the 2-day AC50 value (concentration inducing an avoidance rate of 50%) of IMI was 1.34 (1.02-1.91) mg a.i. kg-1 to E. fetida. For reproduction, the 56-day EC50 value of IMI was 0.87 (0.66-1.33) mg a.i. kg-1 to E. fetida, and there was a positive correlation between the growth rate of earthworms and the number of juveniles in IMI treatments. Activities of carboxylesterase (CarE) and glutathione-S-transferases (GST) in earthworms were disturbed by IMI exposure. Moreover, effects of IMI on the CarE activity in earthworms were more severe and sensitive compared with the GST activity. The expressions of annetocin (ann) and calreticulin (crt) at the transcriptional level were decreased upon IMI exposure, reaching the lowest levels of 0.09 fold and 0.16 fold on day 7 and day 14, respectively. Transcriptionally controlled tumor protein (tctp), heat shock protein 70 (hsp70) and gst exhibited relatively obvious variations (up-regulation or down-regulation) when the exposure duration was extended. Taken together, these results comprehensively contributed to further understandings of the impacts of IMI on earthworms.

Combined effects of four pesticides and heavy metal chromium (â ¥) on the earthworm using avoidance behavior as an endpoint.

In natural ecosystems, organisms are commonly exposed to chemical mixtures rather than individual compounds. However, environmental risk is traditionally assessed based on data of individual compounds. In the present study, we aimed to investigate the individual and combined effects of four pesticides [fenobucarb (FEN), chlorpyrifos (CPF), clothianidin (CLO), acetochlor (ACE)] and one heavy metal chromium [Cr(Ⅵ)] on the earthworm (Eisenia fetida) using avoidance behavior as an endpoint. Our results indicated that CLO had the highest toxicity to E. fetida, followed by Cr(Ⅵ), while FEN showed the least toxicity. Two mixtures of CPF+CLO and Cr(Ⅵ)+CPF+CLO+ACE exhibited synergistic effects on the earthworms. The other two quaternary mixtures of CLO+FEN+ACE+Cr(Ⅵ) and Cr(Ⅵ)+FEN+CPF+ACE at low concentrations also displayed synergistic effects on the earthworms. In contrast, the mixture of Cr(Ⅵ)+FEN had the strongest antagonistic effects on E. fetida. Besides, the quinquenary mixture of Cr(Ⅵ)+FEN+CPF+CLO+ACE also exerted antagonistic effects. These findings highlighted the importance to evaluate chemical mixtures. Moreover, our data strongly pointed out that the avoidance tests could be used to assess the effects of combined effects.

Single and joint toxicity assessment of four currently used pesticides to zebrafish (Danio rerio) using traditional and molecular endpoints.

Pesticides usually present in mixtures in surface waters, although they are traditionally regulated on an individual basis in aquatic ecosystems. In this study, we aimed to investigate the lethal and transcriptional responses of individual and combined pesticides (iprodione, pyrimethanil, pyraclostrobin and acetamiprid) on zebrafish (Danio rerio). Semi-static toxicity test indicated that the greatest toxicity to the four life stages (embryonic, larval, juvenile and adult stages) of D. rerio was detected from pyraclostrobin, followed by iprodione and pyrimethanil. In contrast, the lowest toxicity to the organisms was found from acetamiprid. Most of the selected pesticides exerted greater toxicities to D. rerio of embryonic stage compared with other life stages. Synergistic responses were observed from all binary mixtures of iprodione in combination with pyrimethanil or acetamiprid and ternary mixtures of iprodione+pyraclostrobin in combination with pyrimethanil or acetamiprid. The expressions of 16 genes related to cell apoptosis pathway, oxidative stress response, innate immunity and endocrine disruption at the mRNA level showed that zebrafish embryos were affected by the individual or combined pesticides. The expressions of P53, Tnf, TRß, Tsh and Cyp19a exhibited greater changes upon exposure to combined pesticides compared with individual pesticides. Taken together, increased toxicity might be triggered by the simultaneous presence of several pesticides in the aquatic environment, which seriously damaged the non-target organisms.

Joint acute and endocrine disruptive toxicities of malathion, cypermethrin and prochloraz to embryo-larval zebrafish, Danio rerio.

It remains a daunting challenge to determine ecotoxicological risks of exposure to mixtures of endocrine disrupting chemicals (EDCs) in environmental toxicology. In the present study, we investigated acute and endocrine disruptive toxicities of cypermethrin (CPM), malathion (MAL), prochloraz (PRO) and their binary mixtures of MAL + CPM and MAL + PRO to the early life stages of zebrafish. In the acute lethal toxicity test, three pesticides exhibited different levels of toxicity to zebrafish larvae, and the order of toxicity was as follows: CPM > PRO > MAL. The binary mixture of MAL + CPM displayed a synergistic effect on zebrafish larvae after exposure for 24, 48, 72 and 96 h. However, binary mixture of MAL + PRO showed an antagonistic effect. To evaluate the estrogenic effect, the expression of genes in the hypothalamic-pituitary-gonadal axis was assessed after zebrafish embryos were exposed to CPM, MAL, PRO and their binary mixtures from blastula stage (1 h post-fertilization, 1 hpf) to 14 dpf (14 d post-fertilization). Our data indicated that the transcription patterns of many key genes (vtg1, vtg2, era, erß1, erß2, cyp19a1a and cyp19a1b) were affected in hatched zebrafish after exposure to CPM, MAL and PRO. Moreover, following exposure to binary mixtures of 1000 µg/L MAL +4 µg/L CPM and 1000 µg/L MAL +900 µg/L PRO, the gene expressions were significantly changed compared with the individual pesticides. Our data provided a better understanding of bidirectional interactions of toxic response induced by these pesticides.

Individual and mixture effects of five agricultural pesticides on zebrafish (Danio rerio) larvae.

In the present study, we evaluated the individual and mixture toxicities of imidacloprid and other four pesticides (atrazine, chlorpyrifos, butachlor, and λ-cyhalothrin) to the zebrafish (Danio rerio) larvae in order to clarify the interactive effects of pesticides on aquatic organisms. Results from the 96-h semi-static toxicity test indicated that chlorpyrifos, λ-cyhalothrin, and butachlor had the highest toxicities to D. rerio with an LC50 value ranging from 0.28 (0.13∼0.38) to 0.45 (0.31∼0.59) mg AI L-1, followed by atrazine with an LC50 value of 15.63 (10.71∼25.76) mg AI L-1, while imidacloprid exhibited the least toxicity to the organisms with an LC50 value of 143.7 (99.98∼221.6) mg AI L-1. Seven pesticide mixtures (two binary mixtures of imidacloprid + atrazine and imidacloprid + λ-cyhalothrin, two ternary mixtures of imidacloprid + atrazine + λ-cyhalothrin and imidacloprid + butachlor + λ-cyhalothrin, two quaternary mixtures of imidacloprid + atrazine + chlorpyrifos + λ-cyhalothrin and imidacloprid + chlorpyrifos + butachlor + λ-cyhalothrin, and one quinquenary mixture of imidacloprid + atrazine + chlorpyrifos + butachlor + λ-cyhalothrin) exhibited synergistic effects with equitoxic ratio and equivalent concentration on the zebrafish. Our results highlighted that the simultaneous presence of several pesticides in the aquatic environment might lead to increased toxicity, causing serious damage to the aquatic ecosystems compared with their individual toxicities. Therefore, the toxic effects of both individual pesticides and their mixtures should be incorporated into the environmental risk evaluation of pesticides.

Single and joint toxic effects of five selected pesticides on the early life stages of zebrafish (Denio rerio).

Instead of individual ones, pesticides are usually detected in water environment as mixtures of contaminants. Laboratory tests were conducted in order to investigate the effects of individual and joint pesticides (phoxim, atrazine, chlorpyrifos, butachlor and λ-cyhalothrin) on zebrafish (Denio rerio). Results from 96-h semi-static toxicity test indicated that λ-cyhalothrin had the greatest toxicity to the three life stages (embryonic, larval and juvenile stages) of D. rerio with LC50 values ranging from 0.0031 (0.0017-0.0042) to 0.38 (0.21-0.53) mg a.i. L-1, followed by butachlor and chlorpyrifos with LC50 values ranging from 0.45 (0.31-0.59) to 1.93 (1.37-3.55) and from 0.28 (0.13-0.38) to 13.03 (7.54-19.71) mg a.i. L-1, respectively. In contrast, atrazine showed the least toxicity with LC50 values ranging from 6.09 (3.34-8.35) to 34.19 (24.42-51.9) mg a.i. L-1. The larval stage of D. rerio was a vulnerable period to most of the selected pesticides in the multiple life stages tested. Pesticide mixtures containing phoxim and λ-cyhalothrin exerted synergistic effects on the larvae of D. rerio. Moreover, the binary mixture of phoxim-atrazine also displayed synergistic response to zebrafish. It has been assumed that most chemicals are additive in toxicity. Therefore, it is crucial to clarify the synergistic interaction for pesticide regulators and environment managers. In the present study, our data provided a clear picture on ecological risk of these pesticide mixtures to aquatic organisms. Moreover, joint effects play a more important role than individual ones, which require more attention when defining standard for water environment quality and risk assessment protocols.

Adipose-Derived Stem Cells Alleviate Radiation-Induced Muscular Fibrosis by Suppressing the Expression of TGF-ß1.

We aim to investigate the effects of adipose-derived stem cells (ASCs) transplantation on irradiation-induced skeletal muscle fibrosis. Sixty-four rabbits were randomly divided into ASCs group and PBS group followed by irradiation at unilateral hip with a single dose of 80 Gy. Nonirradiated side with normal skeletal muscle served as normal control. Skeletal muscle tissues were collected from eight rabbits in each group at 1 w, 4 w, 8 w, and 26 w after irradiation. Migration of ASCs was observed in the peripheral tissues along the needle passage in the injured muscle. The proportion of the area of collagen fibers to the total area in sections of ASCs group was lower than those of PBS groups at 4 w, 8 w, and 26 w after irradiation. Significant decrease was noted in the integrated optimal density of the transforming growth factor ß1 (TGF-ß1) in the ASCs group compared with those of PBS group at 4 w, 8 w, and 26 w after irradiation. Moreover, the expression of TGF-ß1 was lower in the ASCs group compared to those of the PBS group at each time point determined by Western blot analysis. ASCs transplantation could alleviate irradiation fibrosis by suppressing the level of TGF-ß1 in the irradiated skeletal muscle.

Carbendazim has the potential to induce oxidative stress, apoptosis, immunotoxicity and endocrine disruption during zebrafish larvae development.

Increasing evidence have suggested deleterious effects of carbendazim on reproduction, apoptosis, immunotoxicity and endocrine disruption in mice and rats, however, the developmental toxicity of carbendazim to aquatic organisms remains obscure. In the present study, we utilized zebrafish as an environmental monitoring model to characterize the effects of carbendazim on expression of genes related to oxidative stress, apoptosis, immunotoxicity and endocrine disruption during larval development. Different trends in gene expression were observed upon exposing the larvae to 4, 20, 100, and 500 µg/L carbendazim for 4 and 8d. The mRNA levels of catalase, glutathione peroxidase and manganese superoxide dismutase (CAT, GPX, and Mn/SOD) were up-regulated after exposure to different concentrations of carbendazim for 4 or 8d. The up-regulation of p53, Apaf1, Cas8 and the down-regulation of Bcl2, Mdm2, Cas3 in the apoptosis pathway, as well as the increased expression of cytokines and chemokines, including CXCL-C1C, CCL1, IL-1b, IFN, IL-8, and TNFα, suggested carbendazim might trigger apoptosis and immune response during zebrafish larval development. In addition, the alteration of mRNA expression of VTG, ERα, ERß1, ERß2, TRα, TRß, Dio1, and Dio2 indicated the potential of carbendazim to induce endocrine disruption in zebrafish larvae. These data suggested that carbendazim could simultaneously induce multiple responses during zebrafish larval development, and bidirectional interactions among oxidative stress, apoptosis pathway, immune and endocrine systems might be present.

Joint toxicity of chlorpyrifos, atrazine, and cadmium at lethal concentrations to the earthworm Eisenia fetida.

Contaminants in the environment often occur as complex mixtures, and their combined effect may exhibit toxicity to organisms. Risk assessments based on individual components tend to underestimate the effects associated with toxic action of mixtures. Toxicity studies on chemical mixtures are urgently required to assess their potential combined toxicities. The combination index (CI)-isobologram method was used to study chemical interactions to determine the nature of toxicological interactions of two pesticides chlorpyrifos and atrazine and a heavy metal cadmium toward earthworm Eisenia fetida by artificial soil and filter paper acute toxicity tests. The results showed that the binary mixture of chlorpyrifos and atrazine was antagonistic toward E. fetida at all f a levels in an artificial soil test. The combination of atrazine and Cd exhibited a slight degree of synergism throughout the exposure range, while chlorpyrifos plus Cd combination led to dual antagonistic/synergistic behavior. The nature of binary combinations in filter paper displayed opposite interaction to that in the artificial soil test, and the toxicity of ternary mixtures was not significantly synergistic than their binaries. The combination index (CI)-isobologram equation method could determine the interaction types for a series of effect levels of three chemicals in binary and ternary combinations in two types of acute earthworm tests. However, the nature of these interactions was not uniform along the f a level range in any of the two tests. Bioavailability, the nature of toxicological interaction, and the test organism need to be considered for understanding exposures and chemical measures. The synergistic effect for the particular binary combination suggests that a potential risk associated with the co-occurrence of these pollutants may still exist, which may have implications in risk assessment for the terrestrial environment. The combined effects between different contaminants might be influenced by the category of chemical, as well as the bioassay procedures. More studies of combined toxicities among these contaminants in the terrestrial environment should be conducted to identify the mixtures exhibiting synergistic pattern of interactions.

Therapeutic potential of adipose stem cells in tissue repair of irradiated skeletal muscle in a rabbit model.

The repairing function and differentiation potency of adipose stem cells (ASCs) transplantation following skeletal muscle injury induced by radiotherapy are still not well defined. In this study, one side of the buttocks of 64 New Zealand white rabbits underwent irradiation and were randomly divided into an ASCs group [5×10(7) ASCs labeled with CM-Dil and suspended in 1 mL of phosphate-buffered saline (PBS), via intramuscular injection] and a PBS group (1 mL of PBS, via intramuascular injection). ASCs were isolated in New Zealand white rabbits in vitro, and migration of ASCs labeled with CM-Dil was observed after transplantation in vivo. A significant decrease of histological severity scoring was found in irradiated tissue obtained in the ASCs group compared with that in PBS group. Additionally, compensatory hyperplasia was noted after ASCs transplantation in the injured tissues. Moreover, ASCs could upregulate the expression of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) and promote the angiogenesis of the injured tissues. Interestingly, myofilament-like structures were identified in irradiated muscle cells after ASCs transplantation. We concluded that ASCs transplantation could repair the radiation-induced skeletal muscle injury. Its mechanism may be, at least partly, associated with the upregulation of VEGF and bFGF, angiogenesis, promoting the compensatory hyperplasia of muscle satellite cells, as well as the myogenic differentiation.

Reduced telomere length in colorectal carcinomas.

PURPOSE: Telomeres play a key role in the maintenance of chromosome integrity and stability, and telomere shortening is involved in initiation and progression of malignancies. The aim of this study was to determine whether telomere length is associated with the colorectal carcinoma. PATIENTS AND METHODS: A total of 148 colorectal cancer (CRC) samples and corresponding adjacent non-cancerous tissues were evaluated for telomere length, P53 mutation, and cyclooxygenase-2 (COX-2) mutation detected by fluorescent immunohistochemistry. Telomere length was estimated by real-time PCR. Samples with a T/S>1.0 have an average telomere length greater than that of the standard DNA; samples with a T/S<1.0 have an average telomere length shorter than that of the standard DNA. RESULTS: Telomeres were shorter in CRCs than in adjacent tissues, regardless of tumor stage and grade, site, or genetic alterations (P=0.004). Telomere length in CRCs also had differences with COX-2 status (P=0.004), but did not differ with P53 status (P=0.101), tumor progression (P=0.244), gender (P=0.542), and metastasis (0.488). There was no clear trend between T/S optimal cut-off values (<1 or > 1) and colorectal tumor progression, metastasis, gender, P53 and COX-2 status. CONCLUSION: These findings suggesting that telomere shortening is associated with colorectal carcinogenesis but does not differ with tumor progression, gender, and metastasis.

Heme oxygenase-1 is induced by thyroid hormone and involved in thyroid hormone preconditioning-induced protection against renal warm ischemia in rat.

Thyroid hormone pretreatment was indicated to increase tissue tolerance to ischemia-reperfusion injury (IRI) in various organs, but the underlying molecular mechanisms remains largely unknown. Induction of heme oxygenase-1 (HO-1) protects organs against IRI. The present study investigated the effect of thyroid hormone on HO-1 expression and the possible relation between HO-1 and the thyroid hormone induced renal protection. T(3) administration in rat kidneys induced HO-1 expression in a time-dependent and dose-dependent way, and its expression was accompanied with significant depletion of reduced glutathione and increase in malondialdehyde content, showing a moderate oxidative stress that turns to normal level 48 h after drug injection. Thyroid hormone pretreatment (10 µg/100g body weight) 48 h before IR procedure significantly decreased serum creatinine and urea nitrogen and preserved renal histology, with significant reduction of parameters about oxidative stress and over-expression of HO-1 compared with that of IR group. In conclusion, T(3) administration involving oxidative stress in kidney exerts significant enhancement of HO-1 expression which may, at least in part, account for the renal preconditioning induced by T(3).