Developmental and heritable genetic defects induced in mice by municipal landfill leachate.

Environmental pollution by solid waste leachate is a serious environmental and public health concern. Leachate contamination and pollution of environmental matrices have been reported, but no report of embryotoxic and developmental defects, and heritable transfer of leachate-induced toxicity in mice. We investigated the ability of Aba-Eku landfill leachate to induce embryonic malformations, developmental toxicity, and germline and somatic DNA damage in the F1 of exposed pregnant mice. Pregnant mice (n = 100) were randomly distributed into 5 experimental groups of 20 animals/group and exposed to 0.2 mL of 5-75% concentrations of the leachate (v/v; Aba-Eku landfill leachate: distilled water) by daily gavage from gestational day (GD) zero to postnatal day (PND) 21. A similar treatment was given to pregnant female mice administered with distilled water (negative control). At GD 18, ten dams from the treatment and control groups were sacrificed by cervical dislocation after which the embryos were collected from the uterus for analyses of fetal morphometric and skeletal metamers respectively. We then monitored the developmental conditions of F1 mice from the remaining ten dams until they were weaned at PND 21 and sacrificed at PND 56 and PND 98 for bone marrow micronucleus and spermiogram analyses respectively. We also analyzed the leachate for inorganic and organic pollutants and calculated the Leachate Pollution Index (LPI). The leachate reduced maternal and fetal birth weight and increased fetal mortality and postnatal appearance of physiological markers in the F1 mice. There was a significant increase (p < 0.05) in the frequency of fetal skeletal malformations, micronucleated polychromatic erythrocytes, and apparent decline of epididymal sperm parameters. The concentrations of the inorganic and organic pollutants, and the LPI exceeded standard limits. Exposure of pregnant female mice to Aba-Eku landfill leachate caused embryonic defects and heritable DNA damage in subsequent generations.

In vitro cytotoxicity of co-exposure to superparamagnetic iron oxide and solid lipid nanoparticles.

Increased production and use of different types of nanoparticles (NPs) in the last decades has led to increased environmental release of these NPs with potential detrimental effects on both the environment and public health. Information is scarce in the literature on the cytotoxic effect of co-exposure to many NPs as this concern is relatively recent. Thus, in this study, we hypothesized scenarios of cell's co-exposure to two kinds of NPs, solid lipid nanoparticles (SLNs) and superparamagnetic iron oxide nanoparticles (SPIONs), to assess the potential cytotoxicity of exposure to NPs combination. Cytotoxicity of SPIONs, SLNs, and their 1:1 mixture (MIX) in six tumor and six non-tumor cell lines was investigated. The mechanisms underlining the induced cytotoxicity were studied through cell cycle analysis, detection of reactive oxygen species (ROS), and alterations in mitochondrial membrane potential (ΔΨM). Double staining with acridine orange and ethidium bromide was also used to confirm cell morphology alterations. The results showed that SPIONs induced low cytotoxicity compared to SLNs. However, the mixture of SPIONs and SLNs showed synergistic, antagonistic, and additive effects based on distinct tests such as viability assay, ROS generation, ΔΨM, and DNA damage, depending on the cell line. Apoptosis triggered by ROS and disturbances in ΔΨM are the most probable related mechanisms of action. As was postulated, there is possible cytotoxic interaction between the two kinds of NPs.

Genetic and systemic toxicity induced by silver and copper oxide nanoparticles, and their mixture in Clarias gariepinus (Burchell, 1822).

Unanticipated increase in the use of silver (Ag) and copper oxide (CuO) nanoparticles (NPs) due to their antimicrobial properties is eliciting environmental health concern because of their coexistence in the aquatic environment. Therefore, we investigated the genetic and systemic toxicity of the individual NPs and their mixture (1:1) using the piscine micronucleus (MN) assay, haematological, histopathological (skin, gills and liver) and hepatic oxidative stress analyses [malondialdehyde (MDA), reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT)] in the African mud catfish, Clarias gariepinus. The fish were exposed to sublethal concentrations (6.25-100.00 mg/L) of each NP and their mixture for 28 days. Both NPs and their mixture induced significant (p < 0.05) increase in MN frequency and other nuclear abnormalities. There was significant decrease in haemoglobin concentration, red and white blood cell counts. Histopathological lesions observed include epidermal skin cells and gill lamellae hyperplasia and necrosis of hepatocytes. The levels of MDA, GSH and activities of SOD and CAT were impacted in C. gariepinus liver following the exposure to the NPs and their mixture. Interaction factor analysis of data indicates antagonistic genotoxicity and oxidative damage of the NPs mixture. These results suggest cytogenotoxic effects of Ag NPs, CuO NPs and their mixture via oxidative stress in Clarias gariepinus.

Chemical characterization of simulated landfill soil leachates from Nigeria and India and their cytotoxicity and DNA damage inductions on three human cell lines.

Landfill soils are sources of emerging carcinogens, teratogens and mutagens in the environment. There is inadequate information on its possible health risk and cytogenotoxicity. This study evaluated chemical characterization of four simulated landfill leachates with their cytotoxicity and DNA damage in human cells. Hepatocarcinoma (HepG2), lymphoma (Jurkat) and osteosarcoma (HOS) cells, incubated with 6.25, 12.5, 25, 50, 75 and 100% of Aba Eku (AEL), Olusosun (OSL), Awotan (AWL) and Nagpur (NPL) simulated leachates for 24 h, were assessed for cell viability using MTT assay and morphological alterations. DNA damage was also assessed after 24 h treatment of cells with sub-lethal concentrations of the leachates using comet assay. Metals and organic compounds in the soil leachates were determined using inductively coupled plasma-mass spectrometry (ICP-MS) and gas chromatography-mass spectroscopy (GC-MS) respectively. The leachates induced significant cytotoxicity in the treated cells with evidence of apoptosis; shrunken morphologies, detachment from the substratum and cytoplasmic vacuolations. Similarly, there was significant DNA damage induced in the treated cells, with increased Olive tail moment, tail length and % tail DNA. Jurkat was the most sensitive (Jurkat > HepG2 > HOS) to the cytotoxic and genotoxic effects of the leachates. All the analyzed metals except Cd, Fe, Zn and Mn were found at levels lower than standard allowable limits. 32, 17, 23 and 23 different PAHs and PCBs were detected in AEL, AWL, OSL and NPL respectively, at varying retention peak times. These toxic constituents induced the observed cytogenotoxicity in the cells and may suggest possible public health risk.

Tumour necrosis factor alpha promoter polymorphism, TNF-238 is associated with severe clinical outcome of falciparum malaria in Ibadan southwest Nigeria.

Tumour necrosis factor (TNF) - α has been shown to play an important role in the pathogenesis of falciparum malaria. Two TNF promoter polymorphisms, TNF-308 and TNF-238 have been associated with differential activity and production of TNF. In order to investigate the association between TNF-308 and TNF-238 and the clinical outcome of malaria in a Nigerian population, the two TNF polymorphisms were analysed using Sequenom iPLEX Platform. A total of 782 children; 283 children with uncomplicated malaria, 255 children with severe malaria and 244 children with asymptomatic infection (controls) were studied. The distribution of TNF-308 and TNF-238 genotypes were consistent with the Hardy-Weinberg equilibrium. Distribution of both TNF polymorphisms differed significantly across all clinical groups (TNF-308: p=0.007; TNF-238: p=0.001). Further tests for association with severe malaria using genotype models controlling for age, parasitaemia and HbAS showed a significant association of the TNF-238 polymorphism with susceptibility to severe malaria (95% CI=1.43-6.02, OR=2.94, p=0.003237) The GG genotype of TNF-238 significantly increased the risk of developing cerebral malaria from asymptomatic malaria and uncomplicated malaria (95% CI=1.99-18.17, OR=6.02, p<0.001 and 95% CI=1.78-8.23, OR=3.84, p<0.001 respectively). No significant association was found between TNF-308 and malaria outcome. These results show thegenetic association of TNF-238 in the clinical outcome of malaria in Ibadan, southwest Nigeria. These findings add support to the role of TNF in the outcome of malaria infection. Further large scale studies across multiple malaria endemic populations will be required to determine the specific roles of TNF-308 and TNF-238 in the outcome of falciparum malaria infection.

Genotoxicity and cytotoxicity of chromium, copper, manganese and lead, and their mixture in WIL2-NS human B lymphoblastoid cells is enhanced by folate depletion.

Heavy metal exposure or dietary deficiency is associated with increased genetic damage, cancer and age-related diseases. Folate (vitamin B9) required for DNA repair and synthesis may increase cellular susceptibility to metal induced genotoxicity. This study investigated the interactive effects of folic acid deficiency and sufficiency on genome instability and cytotoxicity induced by chromium (VI), copper (II), manganese (II), lead (IV), and their mixture (CCMP) in WIL2-NS human B lymphoblastoid cells. WIL2-NS cells were cultured in folic acid deficient (20 nM) and replete (2000 nM) RPMI 1640 medium treated with different concentrations (0.00-1000 µM) of the metals and CCMP for 48 h. Chromosomal damage and cytotoxicity were measured using the Cytokinesis-block Micronucleus Cytome assay. CCMP, Cr, Pb, Cu and Mn induced concentration dependent, increases in cells with chromosome damage (micronuclei, nucleoplasmic bridges, nuclear buds) and necrotic cells and decreased nuclear division index. The metals exhibited different cytotoxic and genotoxic potentials (CCMP>Cr>Pb>Cu>Mn) in both folate deficient and sufficient cells, with the cytogenotoxic effects being greater in folate deficient cells. Significant interaction between the metals and folic acid suggests that folic acid deficiency exacerbated cell proliferation inhibition and genome instability induced by metals. Folate deficiency, increasing metal concentration, and their interactions explained 3-11%, 74-92% and 4-12% of the variance of DNA damage biomarkers. In conclusion, exposure to the tested metals (0.01-1000 µM) increased chromosomal DNA damage in WIL2-NS cells and this was exacerbated by folate deficiency.

Genotoxicity and antigenotoxicity study of aqueous and hydro-methanol extracts of Spondias mombin L., Nymphaea lotus L. and Luffa cylindrical L. using animal bioassays.

Spondias mombin (Linn), Nymphaea lotus (Linn) and Luffa cylindrica (Linn) (syn Luffa aegyptiaca Mill) are plants traditionally used as food ingredients and in the management of diseases, including cancer, in Nigeria. Despite the therapeutic potentials attributed to these plants, reports on their genotoxicity are scanty. In this study, the genotoxicity of the aqueous and hydro-methanol extract of these plants was evaluated using mouse bone marrow micronucleus and sperm morphology assays. Antigenotoxicity was assessed by the bone marrow micronucleus test. The highest attainable dose of 5 000 mg/kg according to OECD guidelines was first used to assess acute toxicity of the aqueous and hydro-methanol extracts in Swiss albino mice. For each extract, there were five groups of mice (n=4/group) treated with different concentrations of the extract as against the negative and positive control group for the genotoxicity study. In the antigenotoxicity study, five groups of mice were exposed to five different concentrations of the extracts along with 60 mg/kg of methyl methane sulfonate (MMS), which was used to induce genotoxicity. The mice were administered 0.2 mL of extract per day for 10 days in the genotoxicity and antigenotoxicity groups. Administration of each of the extracts at the concentration of 5 000 mg/kg did not induce acute toxicity in mice. At the concentrations tested, all the extracts, except aqueous S. mombin, increased micronucleated polychromatic erythrocytes. The aqueous and hydro-methanol extracts of N. lotus increased the frequency of aberrant sperm cells. All the extracts were also able to ameliorate MMS induced genotoxicity in bone marrow cells of the exposed mice. The results showed the potential of the extracts to induce somatic and germ cell mutation in male mice. The extracts also ameliorated the genotoxic effect of MMS.

DNA and oxidative damage induced in somatic organs and tissues of mouse by municipal sludge leachate.

Pollution by waste landfill leachate has prompted a number of studies on the toxic and potential health effects. This study assessed the genotoxicity of a municipal sludge leachate (MSL) in the somatic tissues (blood and bone marrow) and organs (liver, kidney, and spleen) of mice using the alkaline Comet assay. The possible cause of DNA damage via the study of antioxidant system (lipid peroxidation [LPO]; catalase [CAT]; reduced glutathione [GSH]; and superoxide dismutase [SOD]) responses in mouse liver was also investigated. Different concentrations (2.5%, 5%, 10%, and 15%) of the leachate were administered intraperitoneally for 5 consecutive days to male Swiss albino mice (4 mice/group). A significant (p < 0.05) increase in DNA damage in organs and tissues of treated mice compared to the negative control was observed as evident from the Comet assay parameters: olive tail moment (OTM, arbitrary units) and tail DNA (%). Bone marrow showed maximum DNA damage followed by liver > spleen > kidney > blood as evident by the OTM. A significant increase (p < 0.05) in the level of antioxidant enzymes (CAT and SOD) and LPO with a concurrent decrease in GSH in the liver of treated mice was also observed. Our finding demonstrates that the MSL induces DNA damage in the somatic tissues and organs of mouse as well as induces oxidative stress in the liver. These tissues and organs may be the potential targets in animal and human populations exposed to MSL. This is of relevance to public health; as such exposure could lead to adverse health effects via systemic genotoxicity.

Genotoxicity assessment of a pharmaceutical effluent using four bioassays

Pharmaceutical industries are among the major contributors to industrial waste. Their effluents when wrongly handled and disposed of endanger both human and environmental health. In this study, we investigated the potential genotoxicity of a pharmaceutical effluent, by using the Allium cepa, mouse- sperm morphology, bone marrow chromosome aberration (CA) and micronucleus (MN) assays. Some of the physico-chemical properties of the effluent were also determined. The A. cepa and the animal assays were respectively carried out at concentrations of 0.5, 1, 2.5, 5 and 10 percent; and 1, 5, 10, 25 and 50 percent of the effluent. There was a statistically different (p < 0.05), concentration-dependent inhibition of onion root growth and mitotic index, and induction of chromosomal aberrations in the onion and mouse CA test. Assessment of sperm shape showed that the fraction of the sperm that was abnormal in shape was significantly (p < 0.05) greater than the negative control value. MN analysis showed a dose-dependent induction of micronucleated polychromatic erythrocytes across the treatment groups. These observations were provoked by the toxic and genotoxic constituents present in test samples. The tested pharmaceutical effluent is a potentially genotoxic agent and germ cell mutagen, and may induce adverse health effects in exposed individuals.