Adverse effect of tannery waste leachates in transgenic Drosophila melanogaster: role of ROS in modulation of Hsp70, oxidative stress and apoptosis.
Leachate is a complex chemical mixture of chemicals produced as a result of leaching of solid wastes. The potential toxicity of leachates is a major environmental health concern. The present study evaluated the role of ROS in tannery leachates induced Hsp70 expression, antioxidant enzymes and apoptosis in Drosophila. Different concentrations (0.05-2.0%) of leachates prepared from tannery waste at different pH (7.00, 4.93 and 2.88) were mixed with Drosophila food and fed to the larvae for 2-48 h to examine the different stress and apoptotic markers. A concentration- and time-dependent significant increase in Hsp70 expression, ROS generation, antioxidant enzymes activities and MDA content were observed in the exposed larvae. Activities of antioxidant enzymes were delayed compared with Hsp70 expression and MDA level in the exposed organisms. Apoptotic cell death was observed in the exposed larvae at higher concentrations concurrent with a significant regression in Hsp70 along with a higher level of ROS generation. A positive correlation drawn between ROS generation and apoptotic markers and a negative correlation between apoptotic markers and Hsp70 expression at these concentrations indicated the important role of ROS in the induction of cellular damage in the exposed organisms. There was a significant generation of ROS in the larvae exposed to 0.5% of leachates which did not interfere with the protection of their cells by Hsp70 and antioxidant enzymes. However, generation of significantly higher levels of ROS in the larvae exposed to 1.0% and 2.0% leachates may decrease Hsp70 expression thus leading to mitochondria-mediated caspase-dependent apoptotic cell death.
Siddique
Hifzur R
HR
Embryotoxicology Section, Industrial Toxicology Research Centre, P. O. Box No. 80, M. G. Marg, Lucknow 226 001, Uttar Pradesh, India.
Gupta
Subash C
SC
Mitra
Kalyan
K
Bajpai
Virendra K
VK
Mathur
Neeraj
N
Murthy
Ramesh C
RC
Saxena
Daya K
DK
Chowdhuri
Debapratim K
DK
D000818:Animals; D030801:Animals, Genetically Modified; D017304:Annexin A5 / Q000378:metabolism; D000975:Antioxidants / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects*; D053453:Caspase 9 / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D045424:Complex Mixtures / Q000032:analysis / Q000633:toxicity; D004331:Drosophila melanogaster; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D007220:Industrial Waste / Q000032:analysis*; D007763:Lac Operon / Q000187:drug effects; D007814:Larva; D015227:Lipid Peroxidation / Q000187:drug effects; D008564:Membrane Potentials / Q000187:drug effects; D019216:Metals, Heavy / Q000633:toxicity; D009598:Nitrophenylgalactosides; D018384:Oxidative Stress / Q000187:drug effects*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012037:Refuse Disposal; D012989:Soil Pollutants / Q000032:analysis / Q000633:toxicity; D013482:Superoxide Dismutase / Q000378:metabolism; D013633:Tanning; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*
D017304:Annexin A5; D000975:Antioxidants; D045424:Complex Mixtures; D018840:HSP70 Heat-Shock Proteins; D007220:Industrial Waste; D019216:Metals, Heavy; D017382:Reactive Oxygen Species; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; C055012:2-nitrophenylgalactoside; D009598:Nitrophenylgalactosides; D002374:Catalase; D013482:Superoxide Dismutase; D053453:Caspase 9