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Multiwall carbon nanotubes induce apoptosis in rat lung epithelial cells through activation of caspases
Author(s) -
Ravichandran Prabakaran,
Periyakaruppan Adaikkappan,
Gopikrishnan Ramya,
Biradar Santhoshkumar,
Ramesh Vani,
Hall Joseph C,
Meyyappan Meyya,
Ramesh Govindarajan
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.726.6
Subject(s) - dna fragmentation , reactive oxygen species , apoptosis , tunel assay , mtt assay , chemistry , microbiology and biotechnology , fragmentation (computing) , lipid peroxidation , a549 cell , caspase , programmed cell death , oxidative stress , biophysics , biochemistry , biology , ecology
Carbon nanotubes (CNTs), the most promising material with unique characteristics, find its application in different fields ranging from composite materials to medicine and from electronics to energy storage. However, little is known about the mechanism behind the interaction of these particles with cells and their biocompatibility. Therefore, in the present study, we treated rat lung epithelial cells (LE) with 0.5 to 10μg/ml of multiwall carbon nanotubes (MWCNTs) and investigated their effects on cell proliferation and cell death. MTT assay showed a significant dose dependent inhibition of cell proliferation in MWCNT treated cells as compared to control cells, which is also reconfirmed using live‐dead cell assay. MWCNT induces reactive oxygen species in a dose dependent manner in LE cells. Dose dependent increase in the level of lipid peroxidation was observed in these cells, which directly correlates with increased ROS levels. The reductions of glutathione and superoxide dismutase level also were detected in cells treated with MWCNT than control. The time dependent and dose dependent increase in the level of caspase 3 and 8 activities was observed in treated cells as compared to control. DNA fragmentation was increased in a dose dependent manner with corresponding increased concentration of MWCNT than control cells. TUNEL assay showed no significant incorporation of dUTPs in cells incubated with z‐VAD‐fmk , the caspase inhibitor, which confirmed the role of caspases in DNA fragmentation. Together, our results show that that MWCNTs induce the generation of reactive radicals and activates the initiator and effectors caspases in LE cells and that this sequence of events triggers apoptosis cascade. This work was supported by NASA: NCC‐1‐02038 and NIH‐1P20MD001822‐1.